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Versions: 00 01 02 03 04 05 06 07 08 09 10 RFC 2459

PKIX Working Group                                   R. Housley (SPYRUS)
Internet Draft                                        W. Ford (Verisign)
                                                          W. Polk (NIST)
                                                           D. Solo (BBN)
expires in six months                                   October 14, 1997


                   Internet Public Key Infrastructure

                   X.509 Certificate and CRL Profile

                  <draft-ietf-pkix-ipki-part1-06.txt>


Status of this Memo

   This document is an Internet-Draft.  Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
   and its working groups.  Note that other groups may also distribute
   working documents as Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet- Drafts as reference
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   To learn the current status of any Internet-Draft, please check the
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   ftp.isi.edu (US West Coast).


Abstract

   This is the sixth draft of the Internet Public Key Infrastructure
   X.509 Certificate and CRL Profile.  This draft is a complete
   specification.  This text includes minor modifications over the
   previous draft.  Please send comments on this document to the ietf-
   pkix@tandem.com mail list.


1  Executive Summary

   This specification is one part of a multipart standard for the Public
   Key Infrastructure (PKI) for the Internet.  This specification is a
   standalone document; implementations of this standard may proceed
   independent from the other parts.



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   This specification profiles the format and semantics of certificates
   and certificate revocation lists for the Internet PKI.  Procedures
   are described for processing of certification paths in the Internet
   environment.  Encoding rules are provided for popular cryptographic
   algorithms.  Finally, ASN.1 modules are provided in the appendices
   for all data structure defined or referenced.

   The specification describes the requirements which inspire the
   creation of this document and the assumptions which affect its scope
   in Section 2.  Section 3 presents an architectural model and
   describes its relationship to previous IETF and ISO standards.  In
   particular, this document's relationship with the IETF PEM
   specifications and the ISO X.509 documents are described.

   The specification profiles the X.509 version 3 certificate in Section
   4, and the X.509 version 2 certificate revocation list (CRL) in
   Section 5. The profiles include the identification of ISO and ANSI
   extensions which may be useful in the Internet PKI and definition of
   new extensions to meet the Internet's requirements. The profiles are
   presented in the 1988 Abstract Syntax Notation One (ASN.1) rather
   than the 1993 syntax used in the ISO standards.  The ASN.1 notation
   assumes implict tagging throughout.

   This specification also includes path validation procedures in
   Section 6.  These procedures are based upon the ISO definition, but
   the presentation assumes a self-signed root certificate.
   Implementations are required to derive the same results but are not
   required to use the specified procedures.

   Finally, Section 7 of the specification describes procedures for
   identification and encoding of public key materials and digital
   signatures.  Implementations are not required to use any particular
   cryptographic algorithms.  However, conforming implementations which
   use the identified algorithms are required to identify and encode the
   public key materials and digital signatures as described.

   Appendix A contains all ASN.1 structures defined or referenced within
   this specification.  As above, the material is presented in the 1988
   Abstract Syntax Notation One (ASN.1) rather than the 1993 syntax.
   Appendix B contains the same information in the 1993 ASN.1 notation.
   Appendix C contains notes on less familiar features of the ASN.1
   notation used within this specification.  Appendix D contains
   examples of a conforming certificate and a conforming CRL.

2  Requirements and Assumptions

   Goal is to develop a profile and associated management structure to
   facilitate the adoption/use of X.509 certificates within Internet



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   applications for those communities wishing to make use of X.509
   technology. Such applications may include WWW, electronic mail, user
   authentication, and IPSEC, as well as others.  In order to relieve
   some of the obstacles to using X.509 certificates, this document
   defines a profile to promote the development of certificate
   management systems; development of application tools; and
   interoperability determined by policy, as opposed to syntax.

   Some communities will need to supplement, or possibly replace, this
   profile in order to meet the requirements of specialized application
   domains or environments with additional authorization, assurance, or
   operational requirements.  However, for basic applications, common
   representations of frequently used attributes are defined so that
   application developers can obtain necessary information without
   regard to the issuer of a particular certificate or certificate
   revocation list (CRL).

   A certificate user should review the certification practice Statement
   (CPS) generated by the CA before relying on the authentication or
   non-repudiation services associated with the public key in a
   particular certificate.  To this end, this standard does not
   prescribe legally binding rules or duties.

   As supplemental authorization and attribute management tools emerge,
   such as attribute certificates, it may be appropriate to limit the
   authenticated attributes that are included in a certificate.  These
   other management tools may be more appropriate method of conveying
   many authenticated attributes.

2.1  Communication and Topology

   The users of certificates will operate in a wide range of
   environments with respect to their communication topology, especially
   users of secure electronic mail.  This profile supports users without
   high bandwidth, real-time IP connectivity, or high connection
   availablity.  In addition, the profile allows for the presence of
   firewall or other filtered communication.

   This profile does not assume the deployment of an X.500 Directory
   system.  The profile does not prohibit the use of an X.500 Directory,
   but other means of distributing certificates and certificate
   revocation lists (CRLs) are supported.

2.2  Acceptability Criteria

   The goal of the Internet Public Key Infrastructure (PKI) is to meet
   the needs of deterministic, automated identification, authentication,
   access control, and authorization functions. Support for these



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   services determines the attributes contained in the certificate as
   well as the ancillary control information in the certificate such as
   policy data and certification path constraints.

2.3  User Expectations

   Users of the Internet PKI are people and processes who use client
   software and are the subjects named in certificates.  These uses
   include readers and writers of electronic mail, the clients for WWW
   browsers, WWW servers, and the key manager for IPSEC within a router.
   This profile recognizes the limitations of the platforms these users
   employ and the sophistication/attentiveness of the users themselves.
   This manifests itself in minimal user configuration responsibility
   (e.g., root keys, rules), explicit platform usage constraints within
   the certificate, certification path constraints which shield the user
   from many malicious actions, and applications which sensibly automate
   validation functions.

2.4  Administrator Expectations

   As with users, the Internet PKI profile is structured to support the
   individuals who generally operate Certification Authorities (CAs).
   Providing administrators with unbounded choices increases the chances
   that a subtle CA administrator mistake will result in broad
   compromise.  Also, unbounded choices greatly complicates the software
   that must process and validate the  certificates created by the CA.

3  Overview of Approach

   Following is a simplified view of the architectural model assumed by
   the PKIX specifications.




















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      +---+
      | C |                       +------------+
      | e | <-------------------->| End entity |
      | r |       Operational     +------------+
      | t |       transactions         ^
      |   |      and management        |  Management
      | / |       transactions         |  transactions
      |   |                            |
      | C |    PKI users               v
      | R |             -------+-------+--------+------
      | L |   PKI management   ^                ^
      |   |      entities      |                |
      |   |                    v                |
      | R |                 +------+            |
      | e | <-------------- | RA   | <-----+    |
      | p |   certificate   |      |       |    |
      | o |       publish   +------+       |    |
      | s |                                |    |
      | I |                                v    v
      | t |                            +------------+
      | o | <--------------------------|     CA     |
      | r |   certificate publish      +------------+
      | y |           CRL publish             ^
      |   |                                   |
      +---+                                   |    Management
                                              |    transactions
                                              v
                                          +------+
                                          |  CA  |
                                          +------+

                          Figure 1 - PKI Entities

   The components in this model are:

   end entity:  user of PKI certificates and/or end user system that
                is the subject of a certificate;
   CA:          certification authority;
   RA:          registration authority, i.e., an optional system to
                which a CA delegates certain management functions;
   repository:  a system or collection of distributed systems that
                store certificates and CRLs and serves as a means of
                distributing these certificates and CRLs to end
                entities.







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3.1  X.509 Version 3 Certificate

   Application of public key technology requires the user of a public
   key to be confident that the public key belongs to the correct remote
   subject (person or system) with which an encryption or digital
   signature mechanism will be used.  This confidence is obtained
   through the use of public key certificates, which are data structures
   that bind public key values to subjects.  The binding is achieved by
   having a trusted certification authority (CA) digitally sign each
   certificate.  A certificate has a limited valid lifetime which is
   indicated in its signed contents.  Because a certificate's signature
   and timeliness can be independently checked by a certificate-using
   client, certificates can be distributed via untrusted communications
   and server systems, and can be cached in unsecured storage in
   certificate-using systems.

   The standard known as ITU-T X.509 (formerly CCITT X.509) or ISO/IEC
   9594-8, which was first published in 1988 as part of the X.500
   Directory recommendations, defines a standard certificate format. The
   certificate format in the 1988 standard is called the version 1 (v1)
   format.  When X.500 was revised in 1993, two more fields were added,
   resulting in the version 2 (v2) format. These two fields are used to
   support directory access control.

   The Internet Privacy Enhanced Mail (PEM) proposals, published in
   1993, include specifications for a public key infrastructure based on
   X.509 v1 certificates [RFC 1422].  The experience gained in attempts
   to deploy RFC 1422 made it clear that the v1 and v2 certificate
   formats are deficient in several respects.  Most importantly, more
   fields were needed to carry information which PEM design and
   implementation experience has proven necessary.  In response to these
   new requirements, ISO/IEC and ANSI X9 developed the X.509 version 3
   (v3) certificate format.  The v3 format extends the v2 format by
   adding provision for additional extension fields.  Particular
   extension field types may be specified in standards or may be defined
   and registered by any organization or community. In June 1996,
   standardization of the basic v3 format was completed [X.509-AM].

   ISO/IEC and ANSI X9 have also developed standard extensions for use
   in the v3 extensions field [X.509-AM][X9.55].  These extensions can
   convey such data as additional subject identification information,
   key attribute information, policy information, and certification path
   constraints.

   However, the ISO/IEC and ANSI standard extensions are very broad in
   their applicability.  In order to develop interoperable
   implementations of X.509 v3 systems for Internet use, it is necessary
   to specify a profile for use of the X.509 v3 extensions tailored for



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   the Internet.  It is one goal of this document to specify a profile
   for Internet WWW, electronic mail, and IPSEC applications.
   Environments with additional requirements may build on this profile
   or may replace it.

3.2  Certification Paths and Trust

   A user of a security service requiring knowledge of a public key
   generally needs to obtain and validate a certificate containing the
   required public key.  If the public-key user does not already hold an
   assured copy of the public key of the CA that signed the certificate,
   then it might need an additional certificate to obtain that public
   key.  In general, a chain of multiple certificates may be needed,
   comprising a certificate of the public key owner (the end entity)
   signed by one CA, and zero or more additional certificates of CAs
   signed by other CAs.  Such chains, called certification paths, are
   required because a public key user is only initialized with a limited
   number of assured CA public keys.

   There are different ways in which CAs might be configured in order
   for public key users to be able to find certification paths.  For
   PEM, RFC 1422 defined a rigid hierarchical structure of CAs.  There
   are three types of PEM certification authority:

      (a)  Internet Policy Registration Authority (IPRA):  This
      authority, operated under the auspices of the Internet Society,
      acts as the root of the PEM certification hierarchy at level 1.
      It issues certificates only for the next level of authorities,
      PCAs.  All certification paths start with the IPRA.

      (b)  Policy Certification Authorities (PCAs):  PCAs are at level 2
      of the hierarchy, each PCA being certified by the IPRA.  A PCA
      must establish and publish a statement of its policy with respect
      to certifying users or subordinate certification authorities.
      Distinct PCAs aim to satisfy different user needs. For example,
      one PCA (an organizational PCA) might support the general
      electronic mail needs of commercial organizations, and another PCA
      (a high-assurance PCA) might have a more stringent policy designed
      for satisfying legally binding signature requirements.

      (c)  Certification Authorities (CAs):  CAs are at level 3 of the
      hierarchy and can also be at lower levels. Those at level 3 are
      certified by PCAs.  CAs represent, for example, particular
      organizations, particular organizational units (e.g., departments,
      groups, sections), or particular geographical areas.

   RFC 1422 furthermore has a name subordination rule which requires
   that a CA can only issue certificates for entities whose names are



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   subordinate (in the X.500 naming tree) to the name of the CA itself.
   The trust associated with a PEM certification  path is implied by the
   PCA name. The name subordination rule ensures that CAs below the PCA
   are sensibly constrained as to the set of subordinate entities they
   can certify (e.g., a CA for an organization can only certify entities
   in that organization's name tree). Certificate user systems are able
   to mechanically check that the name subordination rule has been
   followed.

   The RFC 1422 was based upon the X.509 v1 certificate formats. The
   limitations of X.509 v1 required imposition of several structural
   restrictions to clearly associate policy information or restrict the
   utility of certificates.  These restrictions included:

      (a) a pure top-down hierarchy, with all certification paths
      starting from the root;

      (b) a naming subordination rule restricting the names of a CA's
      subjects; and

      (c) use of the PCA concept, which requires knowledge of individual
      PCAs to be built into certificate chain verification logic.
      Knowledge of individual PCAs was required to determine if a chain
      could be accepted.

   With X.509 v3, most of the requirements addressed by RFC 1422 can be
   addressed using certificate extensions, without a need to restrict
   the CA structures used.  In particular, the certificate extensions
   relating to certificate policies obviate the need for PCAs and the
   constraint extensions obviate the need for the name subordination
   rule.  As a result, this document supports a more flexible
   architecture, including:

      (a) Certification paths may start with a public key of a CA in a
      user's own domain, or with the public key of the top of a
      hierarchy.  Starting with the public key of a CA in a user's own
      domain has certain advantages.  In many environments, the local
      domain is often the most trusted.  Initialization and key-pair-
      update operations can often be more effectively conducted between
      an end entity and a local management system.

      (b)  Name constraints may be imposed through explicit inclusion of
      a name constraints extension in a certificate, but are not
      required.

      (c)  Policy extensions and policy mappings replace the PCA
      concept, which permits a greater degree of automation.  The
      application can determine if the certification path is acceptable



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      based on the contents of the certificates instead of a priori
      knowledge of PCAs. This permits the full process of certificate
      chain processing to be implemented in software.

3.3  Revocation

   When a certificate is issued, it is expected to be in use for its
   entire validity period.  However, various circumstances may cause a
   certificate to become invalid prior to the expiration of the validity
   period. Such circumstances might include change of name, change of
   association between subject and CA (e.g., an employee terminates
   employment with an organization), and compromise or suspected
   compromise of the corresponding private key.  Under such
   circumstances, the CA needs to revoke the certificate.

   X.509 defines one method of certificate revocation.  This method
   involves each CA periodically issuing a signed data structure called
   a certificate revocation list (CRL).  A CRL is a time stamped list
   identifying revoked certificates which is signed by a CA and made
   freely available in a public repository.  Each revoked certificate is
   identified in a CRL by its certificate serial number. When a
   certificate-using system uses a certificate (e.g., for verifying a
   remote user's digital signature), that system not only checks the
   certificate signature and validity but also acquires a suitably-
   recent CRL and checks that the certificate serial number is not on
   that CRL.  The meaning of "suitably-recent" may vary with local
   policy, but it usually means the most recently-issued CRL.  A CA
   issues a new CRL on a regular periodic basis (e.g., hourly, daily, or
   weekly).  Entries are added to CRLs as revocations occur, and an
   entry may be removed when the certificate expiration date is reached.

   An advantage of this revocation method is that CRLs may be
   distributed by exactly the same means as certificates themselves,
   namely, via untrusted communications and server systems.

   One limitation of the CRL revocation method, using untrusted
   communications and servers, is that the time granularity of
   revocation is limited to the CRL issue period.  For example, if a
   revocation is reported now, that revocation will not be reliably
   notified to certificate-using systems until the next periodic CRL is
   issued -- this may be up to one hour, one day, or one week depending
   on the frequency that the CA issues CRLs.

   Another potential problem with CRLs is the risk of a CRL growing to
   an entirely unacceptable size.  In the 1988 and 1993 versions of
   X.509, the CRL for the end-user certificates needed to cover the
   entire population of end-users for one CA.  It is desirable to allow
   such populations to be in the range of thousands, tens of thousands,



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   or possibly even hundreds of thousands of users. The end-user CRL is
   therefore at risk of growing to such sizes, which present major
   communication and storage overhead problems.  With the version 2 CRL
   format, introduced along with the v3 certificate format, it becomes
   possible to arbitrarily divide the population of certificates for one
   CA into a number of partitions, each partition being associated with
   one CRL distribution point (e.g., directory entry or URL) from which
   CRLs are distributed.  Therefore, the maximum CRL size can be
   controlled by a CA.  Separate CRL distribution points can also exist
   for different revocation reasons.  For example, routine revocations
   (e.g., name change) may be placed on a different CRL to revocations
   resulting from suspected key compromises, and policy may specify that
   the latter CRL be updated and issued more frequently than the former.

   As with the X.509 v3 certificate format, in order to facilitate
   interoperable implementations from multiple vendors, the X.509 v2 CRL
   format needs to be profiled for Internet use.  It is one goal of this
   document to specify that profile.

   Furthermore, it is recognized that on-line methods of revocation
   notification may be applicable in some environments as an alternative
   to the X.509 CRL.  On-line revocation checking significantly reduces
   the latency between a revocation report and the next issue of a CRL.
   Once the CA accepts the report as authentic and valid, any query to
   the on-line service will correctly reflect the certificate validation
   impacts of the revocation.  However, these methods impose new
   security requirements; the certificate validator must trust the on-
   line validation service while the repository did not need to be
   trusted.

   Therefore, this profile also considers standard approaches to on-line
   revocation notification.  The PKIX series of specifications defines a
   set of standard message formats supporting these functions in
   [PKIXOCSP].  The protocols for conveying these messages in different
   environments are also specified.

3.4  Operational Protocols

   Operational protocols are required to deliver certificates and CRLs
   (or status information) to certificate using client systems.
   Provision is needed for a variety of different means of certificate
   and CRL delivery, including request/delivery procedures based on E-
   mail, http, X.500, and WHOIS++.  These specifications include
   definitions of, and/or references to, message formats and procedures
   for supporting all of the above operational environments, including
   definitions of or references to appropriate MIME content types.

   Operational protocols supporting these functions are defined in the



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   PKIX specifications [PKIXLDAP], [PKIXFTP] and [PKIXOCSP].

3.5  Management Protocols

   Management protocols are required to support on-line interactions
   between Public Key Infrastructure (PKI) components.  For example,
   management protocol might be used between a CA and a client system
   with which a key pair is associated, or between two CAs which cross-
   certify each other.  The set of functions which potentially need to
   be supported by management protocols include:

   (a)  registration:  This is the process whereby a user first makes
   itself known to a CA (directly, or through an RA), prior to that CA
   issuing  a certificate or certificates for that user.

   (b)  initialization:  Before a client system can operate securely it
   is necessary to install in it necessary key materials which have the
   appropriate relationship with keys stored elsewhere in the
   infrastructure.  For example, the client needs to be securely
   initialized with the public key of a CA, to be used in validating
   certificate paths.  Furthermore, a client typically needs to be
   initialized with its own key pair(s).

   (c)  certification:  This  is the process in which a CA issues a
   certificate for a user's public key, and returns that certificate to
   the user's client system and/or posts that certificate in a
   repository.

   (d)  key pair recovery:  As an option, user client key materials
   (e.g., a user's private key used for encryption purposes) may be
   backed up by a CA or a key backup system.  If a user needs to recover
   these backed up key materials (e.g., as a result of a forgotten
   password or a lost key chain file), an on-line protocol exchange may
   be needed to support such recovery.

   (e)  key pair update:  All key pairs need to be updated regularly,
   i.e., replaced with a new key pair, and new certificates issued.

   (f)  revocation request:  An authorized person advises a CA of an
   abnormal situation requiring certificate revocation.

   (g)  cross-certification:  Two CAs exchange the information necessary
   to establish cross-certificates between those CAs.

   Note that on-line protocols are not the only way of implementing the
   above functions.  For all functions there are off-line methods of
   achieving the same result, and this specification does not mandate
   use of on-line protocols.  For example, when hardware tokens are



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   used, many of the functions may be achieved as part of the physical
   token delivery.  Furthermore, some of the above functions may be
   combined into one protocol exchange.  In particular, two or more of
   the registration, initialization, and certification functions can be
   combined into one protocol exchange.

   The PKIX series of specifications defines a set of standard message
   formats supporting the above functions in [PKIXMGMT].  The protocols
   for conveying these messages in different environments (on-line, e-
   mail, and WWW) are also specified in [PKIXMGMT].

4  Certificate and Certificate Extensions Profile

   This section presents a profile for public key certificates that will
   foster interoperability and a reusable public key infrastructure.
   This section is based upon the X.509 V3 certificate format
   [COR95][X.509-AM] and the standard certificate extensions defined in
   the Amendment [X.509-AM].  The ISO documents use the 1993 version of
   ASN.1; while this document uses the 1988 ASN.1 syntax, the encoded
   certificate and standard extensions are equivalent.  This section
   also defines private extensions required to support a public key
   infrastructure for the Internet community.

   Certificates may be used in a wide range of applications and
   environments covering a broad spectrum of interoperability goals and
   a broader spectrum of operational and assurance requirements.  The
   goal of this document is to establish a common baseline for generic
   applications requiring broad interoperability and limited special
   purpose requirements.  In particular, the emphasis will be on
   supporting the use of X.509 v3 certificates for informal internet
   electronic mail, IPSEC, and WWW applications.  Other efforts are
   looking at certificate profiles for payment systems.

4.1  Basic Certificate Fields

   The X.509 v3 certificate basic syntax is as follows.  For signature
   calculation, the certificate is encoded using the ASN.1 distinguished
   encoding rules (DER) [X.208].  ASN.1 DER encoding is a tag, length,
   value encoding system for each element.

   Certificate  ::=  SEQUENCE  {
        tbsCertificate       TBSCertificate,
        signatureAlgorithm   AlgorithmIdentifier,
        signature            BIT STRING  }

   TBSCertificate  ::=  SEQUENCE  {
        version         [0]  EXPLICIT Version DEFAULT v1,
        serialNumber         CertificateSerialNumber,



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        signature            AlgorithmIdentifier,
        issuer               Name,
        validity             Validity,
        subject              Name,
        subjectPublicKeyInfo SubjectPublicKeyInfo,
        issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
                             -- If present, version must be v2 or v3
        subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
                             -- If present, version must be v2 or v3
        extensions      [3]  EXPLICIT Extensions OPTIONAL
                             -- If present, version must be v3
        }

   Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }

   CertificateSerialNumber  ::=  INTEGER

   Validity ::= SEQUENCE {
        notBefore      Time,
        notAfter       Time }

   Time ::= CHOICE {
        utcTime        UTCTime,
        generalTime    GeneralizedTime }

   UniqueIdentifier  ::=  BIT STRING

   SubjectPublicKeyInfo  ::=  SEQUENCE  {
        algorithm            AlgorithmIdentifier,
        subjectPublicKey     BIT STRING  }

   Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension

   Extension  ::=  SEQUENCE  {
        extnID      OBJECT IDENTIFIER,
        critical    BOOLEAN DEFAULT FALSE,
        extnValue   OCTET STRING  }

   The following items describe a proposed use of the X.509 v3
   certificate for the Internet.

4.1.1  Certificate Fields

   The Certificate is a SEQUENCE of three required fields. The fields
   are are described in detail in the following subsections






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4.1.1.1  tbsCertificate

   The first field in the sequence is the tbsCertificate.  This is a
   itself a sequence, and contains the names of the subject and issuer,
   a public key associated with the subject an expiration date, and
   other associated information.  The fields of the basic tbsCertificate
   are described in detail in section 4.1.2; the tbscertificate may also
   include extensions which are described in section 4.2.

4.1.1.2  signatureAlgorithm

   The signatureAlgorithm field contains the algorithm identifier for
   the algorithm used by the CA to sign this certificate.  Section 7.2
   lists the supported signature algorithms.

   An algorithm identifier is defined by the following ASN.1 structure:

   AlgorithmIdentifier  ::=  SEQUENCE  {
        algorithm               OBJECT IDENTIFIER,
        parameters              ANY DEFINED BY algorithm OPTIONAL  }

   and it is used to identify a cryptographic algorithm. The OBJECT
   IDENTIFIER algorithm identifies the algorithm (such as RSA with SHA-
   1). The contents of the optional parameters field will vary according
   to the algorithm identfied and the purpose of the algorithm
   identifier.

   In this case, the parameters field will usually be empty. Section 7.2
   lists the supported algorithms for this specification and describes
   the contents of the parameters fields for each algorithm.

   This field should contain the same algorithm identifier as the
   signature field in the sequence tbsCertificate (see section 4.1.2.3)

4.1.1.3  signature

   The signature field contains a digital signature computed upon the
   ASN.1 DER encoded TBSCertificate.  The ASN.1 DER encoded
   TBSCertificate is used as the input to a one-way hash function.  The
   one-way hash function output value is encrypted (e.g., using RSA
   Encryption) to form the signed quantity.  This signature value is
   then ASN.1 encoded as a BIT STRING and included in the Certificate's
   signature field. The details of this process are specified for each
   of the supported algorithms in Section 7.2.

   By generating this signature, a CA certifies the validity of the
   information in tbscertificate.  In particular, the CA certifies the
   binding between the public key material and the subject of the



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   certificate.

4.1.2  TBSCertificate

   The sequence TBSCertificate is a sequence which contains information
   associated with the subject of the certificate and the CA who issued
   it.  Every TBSCertificate contains the names of the subject and
   issuer, a public key associated with the subject, an expiration date,
   a version number and a serial number; some will contain optional
   unique identifier fields.  The remainder of this section describes
   the syntax and semantics of these fields.  A TBSCertificate may also
   include extensions.  Extensions for the Internet PKI are described in
   Section 4.2.

4.1.2.1  Version

   This field describes the version of the encoded certificate.  When
   extensions are used, as expected in this profile, use X.509 version 3
   (value is 2).  If no extensions are present, but a UniqueIdentifier
   is present, use version 2 (value is 1).  If only basic fields are
   present, use version 1 (the value is omitted from the certificate as
   the default value).

   Implementations should be prepared to accept any version certificate.
   At a minimum, conforming implementations shall recognize version 3
   certificates.

   Generation of version 2 certificates is not expected by
   implementations based on this profile.

4.1.2.2  Serial number

   The serial number is an integer assigned by the certification
   authority to each certificate.  It must be unique for each
   certificate issued by a given CA (i.e., the issuer name and serial
   number identify a unique certificate).

4.1.2.3  Signature

   This field contains the algorithm identifier for the algorithm used
   by the CA to sign the certificate.  Section 7.2 lists the supported
   signature algorithms.

   This field should contain the same algorithm identifier as the
   signatureAlgorithm field in the sequence Certificate (see section
   4.1.1.2).





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4.1.2.4  Issuer Name

   The issuer name identifies the entity who has signed (and issued the
   certificate).  The issuer identity may be carried in the issuer name
   field and/or the issuerAltName extension.  If identity information is
   present only in the issuerAltName extension, then the issuer name may
   be an empty sequence and the issuerAltName extension must be
   critical.

   Where it is non-null, the issuer name field shall contain an X.500
   distinguished name (DN).  The issuer field is defined as the X.501
   type Name.  Name is defined by the following ASN.1 structures:


   Name ::= CHOICE {
     RDNSequence }

   RDNSequence ::= SEQUENCE OF RelativeDistinguishedName

   RelativeDistinguishedName ::=
     SET OF AttributeTypeAndValue

   AttributeTypeAndValue ::= SEQUENCE {
     type     AttributeType,
     value    AttributeValue }

   AttributeType ::= OBJECT IDENTIFIER

   AttributeValue ::= ANY

   -- Directory string type --

   DirectoryString ::= CHOICE {
           teletexString           TeletexString (SIZE (1..maxSize),
           printableString         PrintableString (SIZE (1..maxSize)),
           universalString         UniversalString (SIZE (1..maxSize)),
         bmpString               BMPString (SIZE(1..maxSIZE))
                               }


   The Name describes a hierarchical name composed of attributes, such
   as country name, and corresponding values, such as US.  The type of
   the component AttributeValue is determined by the AttributeType; in
   general it will be a directoryString.

   The directoryString is defined as a choice of PrintableString,
   TeletexString, BMPString and UniversalString.  Conforming CAs shall
   choose from these options as follows:



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      (a) if the character set is sufficient, the string will be
      represented as a PrintableString;

      (b) failing (a), if the teletexString character set is sufficient,
      the string will be represented as a TeletexString;

      (c) failing (a) and (b), if the bMPString character set is
      sufficient the string shall be represented as a BMPString; and

      (d) failing (a), (b) and (c), the string shall be represented as a
      UniversalString.

   Standard sets of attributes have been defined in the X.500 series of
   specifications.  Where CAs issue certificates with X.501 type names,
   it is recommended that these attributes types be used.

4.1.2.5  Validity

   This field indicates the period of validity of the certificate, and
   consists of two dates, the first and last on which the certificate is
   valid.  The certificate validity period is the time interval during
   which the CA warrants that it will maintain information about the
   status of the certificate, i.e. publish revocation data. The field is
   represented as a SEQUENCE of two dates:  the date on which the
   certificate validity period begins (notBefore) and the date on which
   the certificate validity period ends (notAfter).  Both notBefore and
   notAfter may be encoded as UTCTime or GeneralizedTime.

   CAs conforming to this profile shall always encode certificate
   validity dates through the year 2049 as UTCTime; certificate validity
   dates in 2050 or later shall be encoded as GeneralizedTime.

4.1.2.5.1  UTCTime

   The universal time type, UTCTime, is a standard ASN.1 type intended
   for international applications where local time alone is not
   adequate.  UTCTime specifies the year through the two low order
   digits and time is specified to the precision of one minute or one
   second.  UTCTime includes either Z (for Zulu, or Greenwich Mean Time)
   or a time differential.

   For the purposes of this profile, UTCTime values shall be expressed
   Greenwich Mean Time (Zulu) and shall include seconds (i.e., times are
   YYMMDDHHMMSSZ), even where the number of seconds is zero.  Conforming
   systems shall interpret the year field (YY) as follows:

      Where YY is greater than or equal to 50, the year shall be
      interpreted as 19YY; and



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      Where YY is less than 50, the year shall be interpreted as 20YY.

4.1.2.5.2  GeneralizedTime

   The generalized time type, GeneralizedTime, is a standard ASN.1 type
   for variable precision representation of time.  Optionally, the
   GeneralizedTime field can include a representation of the time
   differential between local and Greenwich Mean Time.

   For the purposes of this profile, GeneralizedTime values shall be
   expressed Greenwich Mean Time (Zulu) and shall include seconds (i.e.,
   times are YYYYMMDDHHMMSSZ), even where the number of seconds is zero.
   GeneralizedTime values shall not include fractional seconds.

4.1.2.6  Subject Name

   The subject name identifies the entity associated with the public key
   stored in the subject public key field. The subject identity may be
   carried in the subject field and/or the subjectAltName extension.  If
   identity information is present only in the subjectAltName extension
   (e.g., a key bound only to an email address or URI), then the subject
   name may be an empty sequence and the subjectAltName extension must
   be critical.

   Where it is non-null, the subject name field shall contain an X.500
   distinguished name (DN). The DN must be unique for each subject
   entity certified by the one CA as defined by the issuer name field.
   (A CA may issue more than one certificate with the same DN to the
   same subject entity.)

   The subject name field is defined as the X.501 type Name, and shall
   follow the encoding rules for the issuer name field (see 4.1.2.4).

4.1.2.7  Subject Public Key Info

   This field is used to carry the public key and identify the algorithm
   with which the key is used. The algorithm is identified using the
   algorithmIdentifier structure specified in Section 4.1.1.2. The
   object identifiers for the supported algorithms and the methods for
   encoding the public key materials (public key and parameters) are
   specified in Section 7.3.

4.1.2.8  Unique Identifiers

   The subject and issuer unique identifier are present in the
   certificate to handle the possibility of reuse of subject and/or
   issuer names over time.  This profile recommends that names not be
   reused and that Internet certificates not make use of unique



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   identifiers.  CAs conforming to this profile should not generate
   certificates with unique identifiers.  Applications conforming to
   this profile should be capable of parsing unique identifiers and
   making comparisons.

4.1.2.9 Extensions

   This field may only appear if the version number is 3 (see 4.1.2.x).
   If present, this field is a SEQUENCE of one or more certificate
   extensions. The format and content of certificate extensions in the
   Internet PKI is defined in Section 4.2.

4.2  Certificate Extensions

   The extensions defined for X.509 v3 certificates provide methods for
   associating additional attributes with users or public keys, for
   managing the certification hierarchy, and for managing CRL
   distribution.  The X.509 v3 certificate format also allows
   communities to define private extensions to carry information unique
   to those communities.  Each extension in a certificate may be
   designated as critical or non-critical.  A certificate using system
   (an application validating a certificate) must reject the certificate
   if it encounters a critical extension it does not recognize.  A non-
   critical extension may be ignored if it is not recognized.  The
   following presents recommended extensions used within Internet
   certificates and standard locations for information.  Communities may
   elect to use additional extensions; however, caution should be
   exercised in adopting any critical extensions in certificates which
   might be used in a general context.

   Each extension includes an object identifier and an ASN.1 structure.
   When an extension appears in a certificate, the object identifier
   appears as the field extnID and the corresponding ASN.1 encoded
   structure is the value of the octet string extnValue.  Only one
   instance of a particular extension may appear in a particular
   certificate. For example, a certificate may contain only one
   authority key identifier extension (4.2.1.1).  An extension may also
   include the optional boolean critical; critical's default value is
   FALSE.  The text for each extension specifies the acceptable values
   for the critical field.

   Conforming CAs are required to support the basic Constraints
   extension (Section 4.2.1.10), the key usage extension (4.2.1.3) and
   certificate policies extension (4.2.1.5). If the CA issues
   certificates with an empty sequence for the subject field, the CA
   must support the subjectAltName extension.  If the CA issues
   certificates with an empty sequence for the issuer field, the CA must
   support the issuerAltName extension.  Support for the remaining



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   extensions is optional. Conforming CAs may support extensions that
   are not identified within this specification; certificate issuers are
   cautioned that marking such extensions as critical may inhibit
   interoperability.

   At a minimum, applications conforming to this profile shall recognize
   extensions which shall or may be critical. These extensions are:  key
   usage (4.2.1.3), certificate policies (4.2.1.5), the alternative
   subject name (4.2.1.7), issuer alternative name (4.2.1.8), basic
   constraints (4.2.1.10), name constraints (4.2.1.11), policy
   constraints (4.2.1.12), and extended key usage (4.2.1.14).

   In addition, this profile recommends support for key identifiers
   (4.2.1.1 and 4.2.1.2), CRL distribution points (4.2.1.13), and
   authority information access (4.2.2.1).

4.2.1  Standard Extensions

   This section identifies standard certificate extensions defined in
   [X.509-AM] for use in the Internet Public Key Infrastructure.  Each
   extension is associated with an object identifier defined in [X.509-
   AM].  These object identifiers are members of the
   certificateExtension arc, which is defined by the following:

   certificateExtension  OBJECT IDENTIFIER ::=
                             {joint-iso-ccitt(2) ds(5) 29}
   id-ce                 OBJECT IDENTIFIER ::=  certificateExtension

   4.2.1.1  Authority Key Identifier

   The authority key identifier extension provides a means of
   identifying the particular public key used to sign a certificate.
   This extension would be used where an issuer has multiple signing
   keys (either due to multiple concurrent key pairs or due to
   changeover).  In general, this extension should be included in
   certificates.

   The identification can be based on either the key identifier (the
   subject key identifier in the issuer's certificate) or on the issuer
   name and serial number.  The key identifier method is recommended in
   this profile. Conforming CAs that generate this extension shall
   include or omit both authorityCertIssuer and
   authorityCertSerialNumber. If authorityCertIssuer and
   authorityCertSerialNumber are omitted, the keyIdentifier field shall
   be present.

   This extension shall not be marked critical.




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   id-ce-authorityKeyIdentifier OBJECT IDENTIFIER ::=  { id-ce 35 }

   AuthorityKeyIdentifier ::= SEQUENCE {
        keyIdentifier             [0] KeyIdentifier           OPTIONAL,
        authorityCertIssuer       [1] GeneralNames            OPTIONAL,
        authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL
    }

   KeyIdentifier ::= OCTET STRING

4.2.1.2  Subject Key Identifier

   The subject key identifier extension provides a means of identifying
   the particular public key used in an application.  Where a reference
   to a public key identifier is needed (as with an Authority Key
   Identifier) and one is not included in the associated certificate, a
   SHA-1 hash of the subject public key shall be used.  The hash shall
   be calculated over the value (excluding tag and length) of the
   subject public key field in the certificate.  This extension should
   be marked non-critical.

   id-ce-subjectKeyIdentifier OBJECT IDENTIFIER ::=  { id-ce 14 }

   SubjectKeyIdentifier ::= KeyIdentifier

4.2.1.3  Key Usage

   The key usage extension defines the purpose (e.g., encipherment,
   signature, certificate signing) of the key contained in the
   certificate.  The usage restriction might be employed when a key that
   could be used for more than one operation is to be restricted.  For
   example, when an RSA key should be used only for signing, the
   digitalSignature and nonRepudiation bits would be asserted. Likewise,
   when an RSA key should be used only for key management, the
   keyEncipherment bit would be asserted.  The profile recommends that
   when used, this be marked as a critical extension.

      id-ce-keyUsage OBJECT IDENTIFIER ::=  { id-ce 15 }

      KeyUsage ::= BIT STRING {
           digitalSignature        (0),
           nonRepudiation          (1),
           keyEncipherment         (2),
           dataEncipherment        (3),
           keyAgreement            (4),
           keyCertSign             (5),
           cRLSign                 (6),
           encipherOnly            (7),



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           decipherOnly            (8) }


   Bits in the KeyUsage type are used as follows:

      The digitalSignature bit is asserted when the subject public key
      is used to verifying digital signatures that have purposes other
      than non-repudiation, certificate signature, and CRL signature.
      For example, The digitalSignature bit is asserted when the subject
      public key is used to provide authentication.

      The nonRepudiation bit is asserted when the subject public key is
      used to verifying digital signatures used to provide a non-
      repudiation service which protects against the signing entity
      falsely denying some action, excluding certificate or CRL signing.

      The keyEncipherment bit is asserted when the subject public key is
      used for key transport.  For example, when an RSA key is to be
      used exclusively for key management, then this bit must asserted.

      The dataEncipherment bit is asserted when the subject public key
      is used for enciphering user data, other than cryptographic keys.

      The keyAgreement bit is asserted when the subject public key is
      used for key agreement.  For example, when a Diffie-Hellman key is
      to be used exclusively for key management, then this bit must
      asserted.

      The keyCertSign bit is asserted when the subject public key is
      used for verifying a signature on certificates.  This bit may only
      be asserted in CA certificates.

      The cRLSign bit is asserted when the subject public key is used
      for verifying a signature on CRLs.  This bit may only be asserted
      in CA certificates.

      When the encipherOnly bit is asserted and the keyAgreement bit is
      also set, the subject public key may be used only for enciphering
      data while performing key agreement.  The meaning of the
      encipherOnly bit is undefined in the absence of the keyAgreement
      bit.

      When the decipherOnly bit is asserted and the keyAgreement bit is
      also set, the subject public key may be used only for deciphering
      data while performing key agreement.  The meaning of the
      decipherOnly bit is undefined in the absence of the keyAgreement
      bit.




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      This profile does not restrict the combinations the bits that may
      be set in an instantiation of the keyUsage extension.  However,
      appropriate values for keyUsage extensions for particular
      algorithms are specifed in section 7.3.

4.2.1.4  Private Key Usage Period

   The private key usage period extension allows the certificate issuer
   to specify a different validity period for the private key than the
   certificate. This extension is intended for use with digital
   signature keys.  This extension consists of two optional components
   notBefore and notAfter.  The private key associated with the
   certificate should not be used to sign objects before or after the
   times specified by the two components, respectively. CAs conforming
   to this profile shall not generate certificates with private key
   usage period extensions unless at least one of the two components is
   present.

   This profile recommends against the use of this extension.  CAs
   conforming to this profile shall not generate certificates with
   critical private key usage period extensions. Where used, notBefore
   and notAfter are represented as GeneralizedTime and shall be
   specified and interpreted as defined in Section 4.1.2.5.2.

   id-ce-privateKeyUsagePeriod OBJECT IDENTIFIER ::=  { id-ce 16 }

   PrivateKeyUsagePeriod ::= SEQUENCE {
        notBefore       [0]     GeneralizedTime OPTIONAL,
        notAfter        [1]     GeneralizedTime OPTIONAL }

4.2.1.5  Certificate Policies

   The certificate policies extension contains a sequence of one or more
   policy information terms, each of which consists of an object
   identifier (OID) and optional qualifiers.  These policy information
   terms indicate the policy under which the certificate has been issued
   and the purposes for which the certificate may be used.  This profile
   strongly recommends that a simple OID be present in this field.
   Optional qualifiers which may be present are expected to provide
   information about obtaining CA rules, not change the definition of
   the policy.

   Applications with specific policy requirements are expected to have a
   list of those policies which they will accept and to compare the
   policy OIDs in the certificate to that list.  If this extension is
   critical, the path validation software must be able to interpret this
   extension, or must reject the certificate.  (Applications without
   specific policy requirements are not required to list acceptable



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   policies, and may accept any valid certificate regardless of policy
   even if the extension is marked critical.)

   This specification defines two policy qualifiers types for use by
   certificate policy writers and certificate issuers at their own
   discretion. The qualifier types are the CPS Pointer qualifier, and
   the User Notice qualifier.

   The CPS Pointer qualifier contains a pointer to a Certification
   Practice Statement (CPS) published by the CA.  The pointer is in the
   form of a URI.

   User notice is intended for display to a relying party when a
   certificate is used.  The application software should display all
   user notices in all certificates of the certification path used,
   except that if a notice is duplicated only one copy need be
   displayed.  It is recommended that only the lowest-level certificate
   issued by one organization in a certification path contain a user
   notice.

   The user notice has two optional fields: the noticeRef field and the
   explicitText field.

      The noticeRef field, if used, names an organization and
      identifies, by number, a particular textual statement prepared by
      that organization.  For example, it might identify the
      organization "CertsRUs" and notice number 1.  In a typical
      implementation, the application software will have a notice file
      containing the current set of notices for CertsRUs; the
      application will extract the notice text from the file and display
      it.  Messages may be multilingual, allowing the software to select
      the particular language message for its own environment.

      An explicitText field includes the textual statement directly in
      the certificate.  The explicitText field is a string with a
      maximum size of 200 characters.

   If both the noticeRef and explicitText options are included in the
   one qualifier and if the application software can locate the notice
   text indicated by the noticeRef option then that text should be
   displayed; otherwise, the explicitText string should be displayed.

   id-ce-certificatePolicies OBJECT IDENTIFIER ::=  { id-ce 32 }

   certificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation

   PolicyInformation ::= SEQUENCE {
        policyIdentifier   CertPolicyId,



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        policyQualifiers   SEQUENCE SIZE (1..MAX) OF
                PolicyQualifierInfo OPTIONAL }

   CertPolicyId ::= OBJECT IDENTIFIER

   PolicyQualifierInfo ::= SEQUENCE {
        policyQualifierId   PolicyQualifierId,
        qualifier           ANY DEFINED BY policyQualifierId }

   -- policyQualifierIds for Internet policy qualifiers

   id-qt ::= { id-pkix 2 }  -- pkix arc for qualifier types
   id-qt-cps      OBJECT IDENTIFIER ::=  { id-qt 1 }
   id-qt-unotice  OBJECT IDENTIFIER ::=  { id-qt 2 }

   PolicyQualifierId ::=
                 OBJECT IDENTIFIER ( id-qt-cps | id-qt-unotice )

   Qualifier ::= CHOICE {
        cPSuri         CPSuri,
        userNotice     UserNotice }

   CPSuri ::= IA5String

   UserNotice ::= SEQUENCE {
     noticeRef     NoticeReference OPTIONAL,
     explicitText  DisplayText OPTIONAL}

   NoticeReference ::= SEQUENCE {
     organization  IA5String,
     noticeNumbers SEQUENCE OF INTEGER }

   DisplayText ::= CHOICE {
     visibleString VisibleString,
     bmpString     BMPString }


4.2.1.6  Policy Mappings

   This extension is used in CA certificates.  It lists one or more
   pairs of object identifiers; each pair includes an issuerDomainPolicy
   and a subjectDomainPolicy. The pairing indicates the issuing CA
   considers its issuerDomainPolicy equivalent to the subject CA's
   subjectDomainPolicy.

   The issuing CA's users may accept an issuerDomainPolicy for certain
   applications. The policy mapping tells the issuing CA's users which
   policies associated with the subject CA are comparable to the policy



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   they accept.

   This extension may be supported by CAs and/or applications, and it is
   always non-critical.

   id-ce-policyMappings OBJECT IDENTIFIER ::=  { id-ce 33 }

   PolicyMappings ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE {
        issuerDomainPolicy      CertPolicyId,
        subjectDomainPolicy     CertPolicyId }

4.2.1.7  Subject Alternative Name

   The subject alternative names extension allows additional identities
   to be bound to the subject of the certificate.  Defined options
   include an rfc822 name (electronic mail address), a DNS name, an IP
   address, and a URI.  Other options exist, including completely local
   definitions.  Multiple instances of a name and multiple name forms
   may be included.  Whenever such identities are to be bound into a
   certificate, the subject alternative name (or issuer alternative
   name) extension shall be used.  (Note: a form of such an identifier
   may also be present in the subject distinguished name; however, the
   alternative name extension is the preferred location for finding such
   information.)

   Further, if the only subject identity included in the certificate is
   an alternative name form (e.g., an electronic mail address), then the
   subject distinguished name shall be empty (an empty sequence), and
   the subjectAltName extension shall be present. If the subject field
   contains an empty sequence, the subjectAltName extension shall be
   marked critical.

   Where the subjectAltName extension contains a dNSName, this name may
   contain the wildcard character. An "*" is the wildcard character.
   Where a dNSName includes a wildcard, the subject of this certificate
   is a subnet or a collection of hosts. Examples include *.bar.com and
   www*.bar.com.

   Where the subjectAltName extension contains an rfc822Name, this name
   may also include the wildcard character. Use of the wildcard is
   limited to the host name.

   Where the subjectAltName extension contains a
   uniformResourceIdentifier, the URI is a pointer to a sequence of
   certificates issued by this CA (and optionally other CAs) to this
   subject. The URI may not contain the wildcard character in the host
   name.




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   The URI must be an absolute, not relative, pathname and must specify
   the host. This specification recognizes the following values for the
   URI scheme:  ftp, http, ldap, and mailto.  The mailto scheme
   indicates that mail sent to the specified address will generate an
   electronic mail response (to the sender) containing the subject's
   certificates.  No message is required.  If the URI scheme is ftp,
   then the information is available through anonymous ftp.  If the URI
   scheme is http or ldap, then the information may be retrieved using
   that protocol.

   (If the URI specifies any other scheme, contains a relative pathname,
   or omits the  host, the semantics are not defined by this
   specification.)

   When the subjectAltName extension contains a iPAddress, the address
   shall be stored in the octet string in "network byte order," as
   specified in RFC791. The least significant bit (LSB) of each octet is
   the LSB of the corresponding byte in the network address. For IP
   Version 4, as specified in RFC 791, the octet string must contain
   exactly four octets.  For IP Version 6, as specified in RFC 1883, the
   octet string must contain exactly sixteen octets.

   Alternative names may be constrained in the same manner as subject
   distinguished names using the name constraints extension as described
   in section 4.2.1.11.

   If the subjectAltName extension is present, the sequence must contain
   at least one entry.  Unlike the subject field, conforming CAs shall
   not issue certificates with subjectAltNames containing empty
   GeneralName fields. For example, an rfc822Name is represented as an
   IA5String. While an empty string is a valid IA5String, such an
   rfc822Name is not permitted by this profile.  The behavior of clients
   that encounter such a certificate when processing a certificication
   path is not defined by this profile.

      id-ce-subjectAltName OBJECT IDENTIFIER ::=  { id-ce 17 }

      SubjectAltName ::= GeneralNames

      GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName

      GeneralName ::= CHOICE {
           otherName                       [0]     OtherName,
           rfc822Name                      [1]     IA5String,
           dNSName                         [2]     IA5String,
           x400Address                     [3]     ORAddress,
           directoryName                   [4]     Name,
           ediPartyName                    [5]     EDIPartyName,



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           uniformResourceIdentifier       [6]     IA5String,
           iPAddress                       [7]     OCTET STRING,
           registeredID                    [8]     OBJECT IDENTIFIER}

      OtherName ::= SEQUENCE {
           type-id    OBJECT IDENTIFIER,
           value      [0] EXPLICIT ANY DEFINED BY type-id }

      EDIPartyName ::= SEQUENCE {
           nameAssigner            [0]     DirectoryString OPTIONAL,
           partyName               [1]     DirectoryString }

4.2.1.8  Issuer Alternative Name

   As with 4.2.1.7, this extension is used to associate Internet style
   identities with the certificate issuer.  If the only issuer identity
   included in the certificate is an alternative name form (e.g., an
   electronic mail address), then the issuer distinguished name shall be
   empty (an empty sequence), and the issuerAltName extension shall be
   present. If the subject field contains an empty sequence, the
   issuerAltName extension shall be marked critical.

   Where the issuerAltName extension contains a URI, the following
   semantics shall be assumed: the URI is a pointer to an ASN.1 sequence
   of certificates issued to this CA (and optionally other CAs).  The
   expected values for the URI are those defined in 4.2.1.7. Processing
   rules for other values are not defined by this specification.

   Where the issuerAltName extension contains a dNSName, rfc822Name, or
   a URI, wildcard characters are not permitted.

      id-ce-issuerAltName OBJECT IDENTIFIER ::=  { id-ce 18 }

      IssuerAltName ::= GeneralNames

4.2.1.9  Subject Directory Attributes

   The subject directory attributes extension is not recommended as an
   essential part of this profile, but it may be used in local
   environments.  This extension is always non-critical.

   id-ce-subjectDirectoryAttributes OBJECT IDENTIFIER ::=  { id-ce 9 }

   SubjectDirectoryAttributes ::= SEQUENCE SIZE (1..MAX) OF Attribute







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4.2.1.10  Basic Constraints

   The basic constraints extension identifies whether the subject of the
   certificate is a CA and how deep a certification path may exist
   through that CA.

   The pathLenConstraint field is meaningful only if cA is set to TRUE.
   In this case, it gives the maximum number of CA certificates that may
   follow this certificate in a certification path. A value of zero
   indicates that only an end-entity certificate may follow in the path.
   Where it appears, the pathLenConstraint field must be greater than or
   equal to zero. Where pathLenConstraint does not appear, there is no
   limit to the allowed length of the certification path.

   This profile requires the use of this extension, and it shall always
   be critical for CA certificates.

   id-ce-basicConstraints OBJECT IDENTIFIER ::=  { id-ce 19 }

   BasicConstraints ::= SEQUENCE {
        cA                      BOOLEAN DEFAULT FALSE,
        pathLenConstraint       INTEGER (0..MAX) OPTIONAL }

4.2.1.11  Name Constraints

   The name constraints extension, which shall be used only in a CA
   certificate, indicates a name space within which all subject names in
   subsequent certificates in a certification path must be located.
   Restrictions may apply to the subject distinguished name or subject
   alternative names.  Restrictions are defined in terms of permitted or
   excluded name subtrees.  Any name matching a restriction in the
   excludedSubtrees field is invalid regardless of information appearing
   in the permittedSubtrees.  This extension must be critical.

   Within this profile, the minimum and maximum fields are not used with
   any name forms, thus minimum is always zero, and maximum is always
   absent.

   Restrictions for the rfc822, dNSName, and uri name forms are all
   expressed in terms of strings with wild card matching.  An "*" is the
   wildcard character. For uris and rfc822 names, the restriction
   applies to the host part of the name.  Examples would be foo.bar.com;
   www*.bar.com; *.xyz.com.

   Legacy implementations exist where an RFC 822 name is embeded in the
   subject distinguished name as a PKCS #9 e-mail attribute, which has
   the ASN.1 type EmailAddress.  When rfc822 names are constrained, but
   the certificate does not include a subject alternative name, the



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   rfc822 name constraint must be applied to PKCS #9 e-mail attributes
   in the subject distinguished name. The ASN.1 syntax for EmailAddress
   and the corresponding OID are supplied below.

   EmailAddress ::= IA5String

   pkcs-9 OBJECT IDENTIFIER ::=
          { iso(1) member-body(2) US(840) rsadsi(113549) pkcs(1) 9 }

   emailAddress OBJECT IDENTIFIER ::= { pkcs-9 1 }

   Restrictions of the form directoryName shall be applied to the
   subject field in the certificate and to the subjectAltName extensions
   of type directoryName. Restrictions of the form x400Address shall be
   applied to subjectAltName extensions of type x400Address.

   The syntax and semantics for name constraints for otherName,
   ediPartyName, iPAddress, and registeredID are not defined by this
   specification.

      id-ce-nameConstraints OBJECT IDENTIFIER ::=  { id-ce 30 }

      NameConstraints ::= SEQUENCE {
           permittedSubtrees       [0]     GeneralSubtrees OPTIONAL,
           excludedSubtrees        [1]     GeneralSubtrees OPTIONAL }

      GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree

      GeneralSubtree ::= SEQUENCE {
           base                    GeneralName,
           minimum         [0]     BaseDistance DEFAULT 0,
           maximum         [1]     BaseDistance OPTIONAL }

      BaseDistance ::= INTEGER (0..MAX)

4.2.1.12  Policy Constraints

   The policy constraints extension can be used in certificates issued
   to CAs. The policy constraints extension constrains path validation
   in two ways. It can be used to prohibit policy mapping or require
   that each certificate in a path contain an acceptable policy
   identifier.

   If the inhibitPolicyMapping field is present, the value indicates the
   number of additional certificates that may appear in the path before
   policy mapping is no longer permitted.  For example, a value of one
   indicates that policy mapping may be processed in certificates issued
   by the subject of this certificate, but not in additional



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   certificates in the path.

   If the requireExplicitPolicy field is present, subsequent
   certificates must include an acceptable policy identifier. The value
   of requireExplicitPolicy indicates the number of additional
   certificates that may appear in the path before an explicit policy is
   required.  An acceptable policy identifier is the identifier of a
   policy required by the user of the certification path or the
   identifier of a policy which has been declared equivalent through
   policy mapping.

   Conforming CAs shall not issue certificates where policy constraints
   is a null sequence. That is, at least one of the inhibitPolicyMapping
   field or the requireExplicitPolicy field must be present. The
   behavior of clients that encounter a null policy constraints field is
   not addressed in this profile.

   This extension may be critical or non-critical.

   id-ce-policyConstraints OBJECT IDENTIFIER ::=  { id-ce 36 }

   CertificatePoliciesSyntax ::=
                         SEQUENCE SIZE (1..MAX) OF PolicyInformation

   PolicyConstraints ::= SEQUENCE {
        requireExplicitPolicy           [0] SkipCerts OPTIONAL,
        inhibitPolicyMapping            [1] SkipCerts OPTIONAL }

   SkipCerts ::= INTEGER (0..MAX)

4.2.1.13  CRL Distribution Points

   The CRL distribution points extension identifies how CRL information
   is obtained.  The extension shall be non-critical, but this profile
   recommends support for this extension by CAs and applications.
   Further discussion of CRL management is contained in section 5.

   If the cRLDistributionPoints extension contains a
   DistributionPointName of type URI, the following semantics shall be
   assumed: the URI is a pointer to the current CRL for the associated
   reasons and will be issued by the associated cRLIssuer.  The expected
   values for the URI are those defined in 4.2.1.7. Processing rules for
   other values are not defined by this specification.  If the
   distributionPoint omits reasons, the CRL shall include revocations
   for all reasons. If the distributionPoint omits cRLIssuer, the CRL
   shall be issued by the CA that issued the certificate.

   id-ce-cRLDistributionPoints OBJECT IDENTIFIER ::=  { id-ce 31 }



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   cRLDistributionPoints ::= {
        CRLDistPointsSyntax }

   CRLDistPointsSyntax ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint

   DistributionPoint ::= SEQUENCE {
        distributionPoint       [0]     DistributionPointName OPTIONAL,
        reasons                 [1]     ReasonFlags OPTIONAL,
        cRLIssuer               [2]     GeneralNames OPTIONAL }

   DistributionPointName ::= CHOICE {
        fullName                [0]     GeneralNames,
        nameRelativeToCRLIssuer [1]     RelativeDistinguishedName }

   ReasonFlags ::= BIT STRING {
        unused                  (0),
        keyCompromise           (1),
        cACompromise            (2),
        affiliationChanged      (3),
        superseded              (4),
        cessationOfOperation    (5),
        certificateHold         (6) }

4.2.1.14  Extended key usage field

   This field indicates one or more purposes for which the certified
   public key may be used, in addition to or in place of the basic
   purposes indicated in the key usage extension field.  This field is
   defined as follows:

   id-ce-extKeyUsage OBJECT IDENTIFIER ::= {id-ce 37}

   ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId

   KeyPurposeId ::= OBJECT IDENTIFIER

   Key purposes may be defined by any organization with a need. Object
   identifiers used to identify key purposes shall be assigned in
   accordance with ITU-T Rec. X.660 | ISO/IEC 9834-1.

   This extension may, at the option of the certificate issuer, be
   either critical or non-critical.

   If the extension is flagged critical, then the certificate shall be
   used only for one of the purposes indicated.

   If the extension is flagged non-critical, then it indicates the
   intended purpose or purposes of the key, and may be used in finding



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   the correct key/certificate of an entity that has multiple
   keys/certificates. It is an advisory field and does not imply that
   usage of the key is restricted by the certification authority to the
   purpose indicated. (Using applications may nevertheless require that
   a particular purpose be indicated in order for the certificate to be
   acceptable to that application.)

   If a certificate contains both a critical key usage field and a
   critical extended key usage field, then both fields shall be
   processed independently and the certificate shall only be used for a
   purpose consistent with both fields.  If there is no purpose
   consistent with both fields, then the certificate shall not be used
   for any purpose.

   The following key usage purposes are defined by this profile:

   id-kp OBJECT IDENTIFIER ::= { id-pkix 3 }

   id-kp-serverAuth              OBJECT IDENTIFIER ::=   {id-kp 1}
   -- TLS Web server authentication
   -- Key usage bits that may be consistent: digitalSignature,
   --                         keyEncipherment or keyAgreement
   --
   id-kp-clientAuth              OBJECT IDENTIFIER ::=   {id-kp 2}
   -- TLS Web client authentication
   -- Key usage bits that may be consistent: digitalSignature and/or
   --                            keyAgreement
   --
   id-kp-codeSigning             OBJECT IDENTIFIER ::=   {id-kp 3}
   -- Signing of downloadable executable code
   -- Key usage bits that may be consistent: digitalSignature
   --
   id-kp-emailProtection         OBJECT IDENTIFIER ::=   {id-kp 4}
   -- E-mail protection
   -- Key usage bits that may be consistent: digitalSignature,
   --                         nonRepudiation, and/or (keyEncipherment
   --                         or keyAgreement)
   --
   id-kp-ipsecEndSystem          OBJECT IDENTIFIER ::=   {id-kp 5}
   -- IP security end system (host or router)
   -- Key usage bits that may be consistent: digitalSignature and/or
   --                         (keyEncipherment or keyAgreement)
   --
   id-kp-ipsecTunnel             OBJECT IDENTIFIER ::=   {id-kp 6}
   -- IP security tunnel termination
   -- Key usage bits that may be consistent: digitalSignature and/or
   --                         (keyEncipherment or keyAgreement)
   --



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   id-kp-ipsecUser               OBJECT IDENTIFIER ::=   {id-kp 7}
   -- IP security user
   -- Key usage bits that may be consistent: digitalSignature and/or
   --                         (keyEncipherment or keyAgreement)
   id-kp-timeStamping    OBJECT IDENTIFIER ::= { id-kp 8 }
   -- Binding the hash of an object to a time from an agreed-upon time
   -- source. Key usage bits that may be consistent: digitalSignature,
   --                         nonRepudiation

4.2.2  Private Internet Extensions

   This section defines one new extension for use in the Internet Public
   Key Infrastructure.  This extension may be used to direct
   applications to identify an on-line validation service supporting the
   issuing CA.  As the information may be available in multiple forms,
   each extension is a sequence of IA5String values, each of which
   represents a URI.  The URI implicitly specifies the location and
   format of the information and the method for obtaining the
   information.

   An object identifier is defined for the private extension.  The
   object identifier associated with the private extension is defined
   under the arc id-pe within the id-pkix name space.  Any future
   extensions defined for the Internet PKI will also be defined uder the
   arc id-pe.

      id-pkix  OBJECT IDENTIFIER  ::=
               { iso(1) identified-organization(3) dod(6) internet(1)
                       security(5) mechanisms(5) pkix(7) }

      id-pe  OBJECT IDENTIFIER  ::=  { id-pkix 1 }

4.2.2.1  Authority Information Access

   The authority information access extension indicates how to access CA
   information and services for the issuer of the certificate in which
   the extension appears. Information and services may include on-line
   validation services and CA policy data.  (The location of CRLs is not
   specified in this extension; that information is provided by the
   cRLDistributionPoints extension.)  This extension may be included in
   subject or CA certificates, and it is always non-critical.

   id-pe-authorityInfoAccess OBJECT IDENTIFIER ::= { id-pe 1 }

   AuthorityInfoAccessSyntax  ::=
           SEQUENCE SIZE (1..MAX) OF AccessDescription

   AccessDescription  ::=  SEQUENCE {



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           accessMethod          OBJECT IDENTIFIER,
           accessLocation        GeneralName  }

   id-ad OBJECT IDENTIFIER ::= { id-pkix 48 }

   id-ad-ocsp OBJECT IDENTIFIER ::= { id-ad 1 }

   id-ad-caIssuers OBJECT IDENTIFIER ::= { id-ad 2 }

   Each entry in the sequence AuthorityInfoAccessSyntax describes the
   format and location of additional information about the CA who issued
   the certificate in which this extension appears.

   This profile defines an object identifier for the On-line Certificate
   Status Protocol (OCSP) that will be defined in [PKIXOCSP].  When id-
   ad-ocsp appears as accessMethod, the accessLocation field describes
   the on-line status server and the access protocol to obtain current
   certificate status information for the certificate containing this
   extension.

   This profile defines an object identifier to obtain a description of
   the CAs that have issued certificates superior to the CA that issued
   the certificate containing this extension.  The referenced CA Issuers
   description is intended to aid certificate users in the selection of
   a certification path that terminates at a point trusted by the
   certificate user.  The syntax of the referenced CA Issuers
   description will be defined in [PKIXOCSP].  When id-ad-caIssuers
   appears as accessMethod, the accessLocation field describes the
   referenced description server and the access protocol to obtain
   referenced description.

   Additional access descriptors will likely be defined in the future.

   The authorityInfoAccess extension may be included in a PKCS 7
   encapsulation as an X.501 ATTRIBUTE.  This attribute can then be used
   to locate certificates automatically rather than include the
   certificates directly.  The intended effect is to reduce the size of
   the encapsulated message or object.

   PKCS 9 identifies attributes for inclusion in PKCS 7, referencing
   X.520 standard attributes and defining additional attributes unique
   to PKCS 9. The attributes defined in X.520 are based on the
   definition of ATTRIBUTE in ITU-T X.501 | ISO/IEC 9594-2.

   The following syntax defines authorityInfoAccess as an ATTRIBUTE
   suitable for inclusion in a PKCS #7 message:

   authorityInfoAccess ATTRIBUTE ::= {



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       WITH SYNTAX    authorityInfoAccessSyntax,
       ID             id-pe-authorityInfoAccess }

   Other parts of the PKIX specifications [PKIXOCSP] [PKIXLDAP]
   establish requirements on certificate retrieval mechanisms. It is
   expected that applications using the URI form of the authorityInfo
   field for such a purpose will:

   1.  Prepend a suitable HTTP retrieval primitive to the URL (e.g.
   "GET").

   2.  Append a filename to the URL.

   3.  Use the result to retrieve a file containing the requested
   certificate.

   4.  Use the authorityInfoAccess extension in that and subsequent
   certificates to complete a certificate path.

   The filename will be formed as the IA5string representation of
   SHA1(Issuer DN | certificate serial number) concatenated with ".cer."
   The IA5String representation will display the SHA1 result as a
   hexidecimal number using digits and the lowercase letters 'a' through
   'f.'  The SignerInfo syntax of PKCS 7 provides the necessary
   information as issuerAndSerialNumber.

   The specified file will contain a single DER encoded certficate.

5  CRL and CRL Extensions Profile

   As described above, one goal of this X.509 v2 CRL profile is to
   foster the creation of an interoperable and reusable Internet PKI.
   To achieve this goal, guidelines for the use of extensions are
   specified, and some assumptions are made about the nature of
   information included in the CRL.

   CRLs may be used in a wide range of applications and environments
   covering a broad spectrum of interoperability goals and an even
   broader spectrum of operational and assurance requirements.  This
   profile establishes a common baseline for generic applications
   requiring broad interoperability.  Emphasis is placed on support for
   X.509 v2 CRLs.  The profile defines a baseline set of information
   that can be expected in every CRL.  Also, the profile defines common
   locations within the CRL for frequently used attributes, and common
   representations for these attributes.

   This profile does not define any private Internet CRL extensions or
   CRL entry extensions.



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   Environments with additional or special purpose requirements may
   build on this profile or may replace it.

   Conforming CAs are not required to issue CRLs if other revocation or
   status mechanisms are provided.  Conforming CAs that issue CRLs are
   required to issue version 2 CRLs, and must include the date by which
   the next CRL will be issued in the nextUpdate field (Section
   5.1.2.5).  Conforming applications are required to process version 1
   and 2 CRLs.

5.1  CRL Fields

   The X.509 v2 CRL syntax is as follows.  For signature calculation,
   the data that is to be signed is ASN.1 DER encoded.  ASN.1 DER
   encoding is a tag, length, value encoding system for each element.

   CertificateList  ::=  SEQUENCE  {
        tbsCertList          TBSCertList,
        signatureAlgorithm   AlgorithmIdentifier,
        signature            BIT STRING  }

   TBSCertList  ::=  SEQUENCE  {
        version                 Version OPTIONAL,
                                     -- if present, must be v2
        signature               AlgorithmIdentifier,
        issuer                  Name,
        thisUpdate              Time,
        nextUpdate              Time OPTIONAL,
        revokedCertificates     SEQUENCE OF SEQUENCE  {
             userCertificate         CertificateSerialNumber,
             revocationDate          Time,
             crlEntryExtensions      Extensions OPTIONAL
                                           -- if present, must be v2
                                  }  OPTIONAL,
        crlExtensions           [0]  EXPLICIT Extensions OPTIONAL
                                           -- if present, must be v2
                                  }

   -- Version, Time, CertificateSerialNumber and Extensions
   -- are all defined in the ASN.1 in section 4.1

   AlgorithmIdentifier  ::=  SEQUENCE  {
        algorithm               OBJECT IDENTIFIER,
        parameters              ANY DEFINED BY algorithm OPTIONAL  }
                                -- contains a value of the type
                                -- registered for use with the
                                -- algorithm object identifier value




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   The following items describe the proposed use of the X.509 v2 CRL in
   the Internet PKI.

5.1.1  CertificateList Fields

   The CertificateList is a SEQUENCE of three required fields. The
   fields are are described in detail in the following subsections

5.1.1.1  tbsCertList

   The first field in the sequence is the tbsCertList.  This field is
   itself a sequence containing the name of the issuer, issue date,
   issue date of the next list, the list of revoked certificates, and
   optional CRL extensions.  Further, each entry on the revoked
   certificate list is defined by a sequence of user certificate serial
   number, revocation date, and optional CRL entry extensions.

5.1.1.2  signatureAlgorithm

   The signatureAlgorithm field contains the algorithm identifier for
   the algorithm used by the CA to sign the CertificateList.  Section
   7.2 lists the supported signature algorithms. Conforming CAs shall
   use the algorithm identifiers presented in Section 7.2 when signing
   with a supported signature algorithm.

5.1.1.3  signature

   The signature field contains a digital signature computed upon the
   ASN.1 DER encoded TBSCertList.  The ASN.1 DER encoded  TBSCertList is
   used as the input to a one-way hash function.  The one-way hash
   function output value is encrypted (e.g., using RSA Encryption) to
   form the signed quantity.  This signature value is then ASN.1 encoded
   as a BIT STRING and included in the CRL's signature field. The
   details of this process are specified for each of the supported
   algorithms in Section 7.2.

5.1.2  Certificate List "To Be Signed"

   The certificate list to be signed, or tBSCertList, is a SEQUENCE of
   required and optional fields.  The required fields identify the CRL
   issuer, the algorithm used to sign the CRL, the date and time the CRL
   was issued, and the date and time by which the CA will issue the next
   CRL.

   Optional fields include lists of revoked certificates and CRL
   extensions.  The revoked certificate list is optional to support the
   special case where a CA has not revoked any unexpired certificates it
   has issued.  It is expected that nearly all CRLs issued in the



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   Internet PKI will contain one or more lists of revoked certificates.
   Similarly, the profile requires conforming CAs to use the CRL
   extension cRLNumber in all CRLs issued.

5.1.2.1  Version

   This optional field describes the version of the encoded CRL.  When
   extensions are used, as expected in this profile, this field shall be
   present and shall specify version 2 (the integer value is 1).  If
   neither CRL extensions nor CRL entry extensions are present, version
   1 CRLs are recommended. In this case, the field shall be ommitted.

5.1.2.2  Signature

   This field contains the algorithm identifier for the algorithm used
   to sign the CRL.  Section 7.2 lists OIDs for the most popular
   signature algorithms used in the Internet PKI.

5.1.2.3  Issuer Name

   The issuer name identifies the entity who has signed (and issued the
   CRL).  The issuer identity may be carried in the issuer name field
   and/or the issuerAltName extension.  If identity information is
   present only in the issuerAltName extension, then the issuer name may
   be an empty sequence and the issuerAltName extension must be
   critical.

   Where it is non-null, the issuer name field shall contain an X.500
   distinguished name (DN).  The issuer name field is defined as the
   X.501 type Name, and shall follow the encoding rules for the issuer
   name field in the certificate (see 4.1.2.4).

5.1.2.4  This Update

   This field indicates the issue date of this CRL. ThisUpdate may be
   encoded as UTCTime or GeneralizedTime.

   CAs conforming to this profile that issue CRLs shall encode
   thisUpdate as UTCTime for dates through the year 2049. CAs conforming
   to this profile that issue CRLs shall encode thisUpdate as
   GeneralizedTime for dates in the year 2050 or later.

   Where encoded as UTCTime, thisUpdate shall be specified and
   interpreted as defined in Section 4.1.2.5.1.  Where encoded as
   GeneralizedTime, thisUpdate shall be specified and interpreted as
   defined in Section 4.1.2.5.2.





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5.1.2.5  Next Update

   This field indicates the date by which the next CRL will be issued.
   The next CRL could be issued before the indicated date, but it will
   not be issued any later than the indicated date. nextUpdate may be
   encoded as UTCTime or GeneralizedTime.

   This profile requires inclusion of nextUpdate in all CRLs issued by
   conforming CAs. Note that the ASN.1 syntax of TBSCertList describes
   this field as OPTIONAL, which is consistent with the ASN.1 structure
   defined in [X.509-AM]. The behavior of clients processing CRLs which
   omit nextUpdate is not specified by this profile.

   CAs conforming to this profile that issue CRLs shall encode
   nextUpdate as UTCTime for dates through the year 2049. CAs conforming
   to this profile that issue CRLs shall encode nextUpdate as
   GeneralizedTime for dates in the year 2050 or later.

   Where encoded as UTCTime, nextUpdate shall be specified and
   interpreted as defined in Section 4.1.2.5.1.  Where encoded as
   GeneralizedTime, nextUpdate shall be specified and interpreted as
   defined in Section 4.1.2.5.2.

5.1.2.6  Revoked Certificates

   Revoked certificates are listed.  The revoked certificates are named
   by their serial numbers.  Certificates are uniquely identified by the
   combination of the issuer name or issuer alternative name along with
   the user certificate serial number.  The date on which the revocation
   occurred is specified.  The time for revocationDate shall be
   expressed as described in section 5.1.2.4. Additional information may
   be supplied in CRL entry extensions; CRL entry extensions are
   discussed in section 5.3.

5.1.2.7  Extensions

   This field may only appear if the version number is 2 (see 5.1.2.1).
   If present, this field is a SEQUENCE of one or more CRL extensions.
   CRL extensions are discussed in section 5.2.

5.2  CRL Extensions

   The extensions defined by ANSI X9 and ISO for X.509 v2 CRLs [X.509-
   AM] [X9.55] provide methods for associating additional attributes
   with CRLs.  The X.509 v2 CRL format also allows communities to define
   private extensions to carry information unique to those communities.
   Each extension in a CRL may be designated as critical or non-
   critical.  A CRL validation must fail if it encounters an critical



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   extension which it does not know how to process.  However, an
   unrecognized non-critical extension may be ignored.  The following
   presents those extensions used within Internet CRLs.  Communities may
   elect to include extensions in CRLs which are not defined in this
   specification. However, caution should be exercised in adopting any
   critical extensions in CRLs which might be used in a general context.

   Conforming CAs that issue CRLs are required to support the CRL number
   extension (5.2.3), and include it in all CRLs issued. Conforming
   applications are required to support the critical and optionally
   critical CRL extensions issuer alternative name (5.2.2), issuing
   distribution point (5.2.4) and delta CRL indicator (5.2.5).

5.2.1  Authority Key Identifier

   The authority key identifier extension provides a means of
   identifying the particular public key used to sign a CRL.  The
   identification can be based on either the key identifier (the subject
   key identifier in the CRL signer's certificate) or on the issuer name
   and serial number.  The key identifier method is recommended in this
   profile.  This extension would be used where an issuer has multiple
   signing keys, either due to multiple concurrent key pairs or due to
   changeover.  In general, this non-critical extension should be
   included in certificates.

   The syntax for this CRL extension is defined in Section 4.2.1.1.

5.2.2  Issuer Alternative Name

   The issuer alternative names extension allows additional identities
   to be associated with the issuer of the CRL.  Defined options include
   an rfc822 name (electronic mail address), a DNS name, an IP address,
   and a URI.  Multiple instances of a name and multiple name forms may
   be included.  Whenever such identities are used, the issuer
   alternative name extension shall be used.

   Further, if the only issuer identity included in the CRL is an
   alternative name form (e.g., an electronic mail address), then the
   issuer distinguished name should be empty (an empty sequence), the
   issuerAltName extension should be used, and the issuerAltName
   extension must be marked critical.

   The object identifier and syntax for this CRL extension are defined
   in Section 4.2.1.8.







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5.2.3  CRL Number

   The CRL number is a non-critical CRL extension which conveys a
   monotonically increasing sequence number for each CRL issued by a
   given CA through a specific CA X.500 Directory entry or CRL
   distribution point.  This extension allows users to easily determine
   when a particular CRL supersedes another CRL.  CAs conforming to this
   profile shall include this extension in all CRLs.

   id-ce-cRLNumber OBJECT IDENTIFIER ::= { id-ce 20 }

   cRLNumber ::= INTEGER (0..MAX)

5.2.4  Issuing Distribution Point

   The issuing distribution point is a critical CRL extension that
   identifies the CRL distribution point for a particular CRL, and it
   indicates whether the CRL covers revocation for end entity
   certificates only, CA certificates only, or a limitied set of reason
   codes.  Since this extension is critical, all certificate users must
   be prepared to receive CRLs with this extension.

   The CRL is signed using the CA's private key.  CRL Distribution
   Points do not have their own key pairs.  If the CRL is stored in the
   X.500 Directory, it is stored in the Directory entry corresponding to
   the CRL distribution point, which may be different than the Directory
   entry of the CA.

   CAs may use CRL distribution points to partition the CRL on the basis
   of compromise and routine revocation.  In this case, the revocations
   with reason code keyCompromise (1) shall appear in one distribution
   point, and the revocations with other reason codes shall appear in
   another distribution point. The reason codes associated with a
   distribution point must be specified in onlySomeReasons. If
   onlySomeReasons does not appear, the distribution point must contain
   revocations for all reason codes.

   Where the issuingDistributionPoint extension contains a URL, the
   following semantics shall be assumed: the object is a pointer to the
   most current CRL issued by this CA.  The URI schemes ftp, http,
   mailto [RFC1738] and ldap [RFC1778] are defined for this purpose.
   The URI must be an absolute, not relative, pathname and must specify
   the host.

   id-ce-issuingDistributionPoint OBJECT IDENTIFIER ::= { id-ce 28 }

   issuingDistributionPoint ::= SEQUENCE {
        distributionPoint       [0] DistributionPointName OPTIONAL,



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        onlyContainsUserCerts   [1] BOOLEAN DEFAULT FALSE,
        onlyContainsCACerts     [2] BOOLEAN DEFAULT FALSE,
        onlySomeReasons         [3] ReasonFlags OPTIONAL,
        indirectCRL             [4] BOOLEAN DEFAULT FALSE }

5.2.5  Delta CRL Indicator

   The delta CRL indicator is a critical CRL extension that identifies a
   delta-CRL.  The use of delta-CRLs can significantly improve
   processing time for applications which store revocation information
   in a format other than the CRL structure.  This allows changes to be
   added to the local database while ignoring unchanged information that
   is already in the local database.

   When a delta-CRL is issued, the CAs shall also issue a complete CRL.

   The value of BaseCRLNumber identifies the CRL number of the base CRL
   that was used as the starting point in the generation of this delta-
   CRL.  The delta-CRL contains the changes between the base CRL and the
   current CRL issued along with the delta-CRL.  It is the decision of a
   CA as to whether to provide delta-CRLs.  Again, a delta-CRL shall not
   be issued without a corresponding CRL.  The value of CRLNumber for
   both the delta-CRL and the corresponding CRL shall be identical.

   A CRL user constructing a locally held CRL from delta-CRLs shall
   consider the constructed CRL incomplete and unusable if the CRLNumber
   of the received delta-CRL is more that one greater that the CRLnumber
   of the delta-CRL last processed.

   id-ce-deltaCRLIndicator OBJECT IDENTIFIER ::= { id-ce 27 }

   deltaCRLIndicator ::= BaseCRLNumber

   BaseCRLNumber ::= CRLNumber

5.2.6 Certificate Issuer

   This CRL entry extension identifies the certificate issuer associated
   with an entry in an indirect CRL, i.e. a CRL that has the indirectCRL
   indicator set in its issuing distribution point extension. If this
   extension is not present on the first entry in an indirect CRL, the
   certificate issuer defaults to the CRL issuer. On subsequent entries
   in an indirect CRL, if this extension is not present, the certificate
   issuer for the entry is the same as that for the preceding entry.
   This field is defined as follows:

   id-ce-certificateIssuer   OBJECT IDENTIFIER ::= { id-ce 29 }




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   certificateIssuer ::=     GeneralNames

   If used by conforming CAs that issue CRLs, this extension is always
   critical.  Conforming applications  if an implementation ignored this
   extension it could not correctly attribute CRL entries to
   certificates.

5.3  CRL Entry Extensions

   The CRL entry extensions already defined by ANSI X9 and ISO for X.509
   v2 CRLs [X.509-AM] [X9.55] provide methods for associating additional
   attributes with CRL entries.  The X.509 v2 CRL format also allows
   communities to define private CRL entry extensions to carry
   information unique to those communities.  Each extension in a CRL
   entry may be designated as critical or non-critical.  A CRL
   validation must fail if it encounters a critical CRL entry extension
   which it does not know how to process.  However, an unrecognized
   non-critical CRL entry extension may be ignored.  The following
   presents recommended extensions used within Internet CRL entries and
   standard locations for information.  Communities may elect to use
   additional CRL entry extensions; however, caution should be exercised
   in adopting any critical extensions in CRL entries which might be
   used in a general context.

   All CRL entry extensions are non-critical; support for these
   extensions is optional for conforming CAs and applications.  However,
   CAs that issue CRLs are strongly encouraged to include reason codes
   (5.3.1) whenever this information is available.

5.3.1  Reason Code

   The reasonCode is a non-critical CRL entry extension that identifies
   the reason for the certificate revocation. CAs are strongly
   encouraged to include reason codes in CRL entries; however, the
   reason code CRL entry extension should be absent instead of using the
   unspecified (0) reasonCode value.

   id-ce-cRLReason OBJECT IDENTIFIER ::= { id-ce 21 }

   -- reasonCode ::= { CRLReason }

   CRLReason ::= ENUMERATED {
        unspecified             (0),
        keyCompromise           (1),
        cACompromise            (2),
        affiliationChanged      (3),
        superseded              (4),
        cessationOfOperation    (5),



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        certificateHold         (6),
        removeFromCRL           (8) }

5.3.2  Hold Instruction Code

   The hold instruction code is a non-critical CRL entry extension that
   provides a registered instruction identifier which indicates the
   action to be taken after encountering a certificate that has been
   placed on hold.

   id-ce-holdInstructionCode OBJECT IDENTIFIER ::= { id-ce 23 }

   holdInstructionCode ::= OBJECT IDENTIFIER

   The following instruction codes have been defined.  Conforming
   applications that process this extension shall recognize the
   following instruction codes.

   holdInstruction    OBJECT IDENTIFIER ::=
                    { iso(1) member-body(2) us(840) x9-57(10040) 2 }

   id-holdinstruction-none   OBJECT IDENTIFIER ::= {holdInstruction 1}
   id-holdinstruction-callissuer
                             OBJECT IDENTIFIER ::= {holdInstruction 2}
   id-holdinstruction-reject OBJECT IDENTIFIER ::= {holdInstruction 3}

   Conforming applications which encounter a id-holdinstruction-
   callissuer must call the certificate issuer or reject the
   certificate.  Conforming applications which encounter a id-
   holdinstruction-reject ID shall reject the transaction. id-
   holdinstruction-none is semantically equivalent to the absence of a
   holdInstructionCode.  Its use is strongly deprecated for the Internet
   PKI.

5.3.3  Invalidity Date

   The invalidity date is a non-critical CRL entry extension that
   provides the date on which it is known or suspected that the private
   key was compromised or that the certificate otherwise became invalid.
   This date may be earlier than the revocation date in the CRL entry,
   but it must be later than the issue date of the previously issued
   CRL.  Remember that the revocation date in the CRL entry specifies
   the date that the CA revoked the certificate.  Whenever this
   information is available, CAs are strongly encouraged to share it
   with CRL users.

   The GeneralizedTime values included in this field shall be expressed
   in Greenwich Mean Time (Zulu), and shall be specified and interpreted



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   as defined in Section 4.1.2.5.2.

   id-ce-invalidityDate OBJECT IDENTIFIER ::= { id-ce 24 }

   invalidityDate ::=  GeneralizedTime

6  Certificate Path Validation

   Certification path validation procedures for the Internet PKI are
   based on Section 12.4.3 of [X.509-AM].  Certification path processing
   verifies the binding between the subject distinguished name and
   subject public key.  The binding is limited by constraints which are
   specified in the certificates which comprise the path. The basic
   constraints and policy constraints extensions allow the certification
   path processing logic to automate the decision making process.

   This section describes an algorithm for validating certification
   paths.  Conforming implementations of this specification are not
   required to implement this algorithm, but shall be functionally
   equivalent to the external behaviour resulting from this procedure.
   Any algorithm may be used by a particular implementation so long as
   it derives the correct result.

   The following text assumes that all valid paths begin with the public
   key of a single "most-trusted CA". The "most-trusted CA" is a matter
   of policy: it could be a root CA in a hierarchical PKI; the CA that
   issued the verifier's own certificate(s); or any other CA in a
   network PKI.  The path validation procedure is the same regardless of
   the choice of "most-trusted CA."

   The text assumes that this public key is contained in a "self-signed"
   certificate. This simplifies the description of the path processing
   procedure.  Note that the signature on the self-signed certificate
   does not provide any security services.  The public key it contains
   is trusted because of other procedures used to obtain and protect it.

   The goal of path validation is to verify the binding between a
   subject distinguished name and subject public key, as represented in
   the "end entity" certificate, based on the public key of the "most-
   trusted CA".  This requires obtaining a sequence of certificates that
   support that binding.  The procedures performed to obtain this
   sequence is outside the scope of this section.

   The following text also assumes that certificates do not use subject
   or unique identifier fields or private critical extensions, as
   recommended within this profile.  However, if these components appear
   in certificates, they must be processed.  Finally, policy qualifiers
   are also neglected for the sake of clarity.



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   A certification path is a sequence of n certificates where:

      * for all x in {1,(n-1)}, the subject of certificate x is the
      issuer of certificate x+1.
      * certificate x=1 is the the self-signed certificate, and
      * certificate x=n is the end entity certificate.

   This section assumes the following inputs are provided to the path
   processing logic:

      (a)  a certification path of length n;

      (b)  a set of initial policy identifiers (each comprising a
      sequence of policy element identifiers), which identifies one or
      more certificate policies, any one of which would be acceptable
      for the purposes of certification path processing; and

      (c)  the current date/time (if not available internally to the
      certification path processing module).

   From the inputs, the procedure intializes five state variables:

      (a)  acceptable policy set:  A set of certificate policy
      identifiers comprising the policy or policies recognized by the
      public key user together with policies deemed equivalent through
      policy mapping. The initial value of the acceptable policy set is
      the set of initial policy identifiers.

      (b)  constrained subtrees:  A set of root names defining a set of
      subtrees within which all subject names in subsequent certificates
      in the certification path shall fall. The initial value is
      "unbounded".

      (c)  excluded subtrees:  A set of root names defining a set of
      subtrees within which no subject name in subsequent certificates
      in the certification path may fall. The initial value is "empty".

      (d)  explicit policy: an integer which indicates if an explicit
      policy identifier is required. The integer indicates the first
      certificate in the path where this requirement is imposed. Once
      set, this variable may be decreased, but may not be increased.
      (That is, if a certificate in the path requires explicit policy
      identifiers, a later certificate can not remove this requirement.)
      The initial value is n+1.

      (e)  policy mapping: an integer which indicates if policy mapping
      is permitted.  The integer indicates the last certificate on which
      policy mapping may be applied.  Once set, this variable may be



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      decreased, but may not be increased. (That is, if a certificate in
      the path specifies policy mapping is not permitted, it can not be
      overriden by a later certificate.) The initial value is n+1.

   The actions performed by the path processing software for each
   certificate i=1 through n are described below.  The self-signed
   certificate is certificate i=1, the end entity certificate is i=n.
   The processing is performed sequentially, so that processing
   certificate i affects the state variables for processing certificate
   (i+1).  Note that actions (f) through (i) are not applied to the end
   entity certificate (certificate n).

   The path processing actions to be performed are:

      (a)  Verify the basic certificate information, including:

         (1) the certificate was signed using the subject public key
         from certificate i-1 (in the special case i=1, this step may be
         omitted; if not, use the subject public key from the same
         certificate),

         (2) the certificate is not expired, and (if present) the
         private key usage period is satisfied,

         (3) the certificate has not been revoked (this may be
         determined by obtaining current CRL, current status
         information, or by out-of-band mechanisms), and

         (4) the subject and issuer names chain correctly.  (If the
         certificate has an empty sequence in the name field, name
         chaining will use the critical subjectAltNames and
         issuerAltNames fields.)

      (b)  Verify that the subject name or critical subjectAltName
      extension is consistent with the constrained subtrees state
      variables; and

      (c)  Verify that the subject name or critical subjectAltName
      extension is consistent with the excluded subtrees state
      variables.

      (d)  Verify that policy information is consistent:

         (1) if the explicit policy state variable is less than or equal
         to i, an appropriate policy identifier must appear in the
         certificate; and
         (2) if the policy mapping variable is less than or equal to i,
         the policy identifier may not be mapped.



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      (e)  Recognize and process any other critical extension present in
      the certificate.

      (f) Verify that the certificate is a CA certificate (as specified
      in a basicConstraints extension or as verified out-of-band).

      (g)  If permittedSubtrees is present in the certificate, set the
      constrained subtrees state variable to the intersection of its
      previous value and the value indicated in the extension field.

      (h)  If excludedSubtrees is present in the certificate, set the
      excluded subtrees state variable to the union of its previous
      value and the value indicated in the extension field.

      (i)  If a policy constraints extension is included in the
      certificate, modify the explicit policy and policy mapping state
      variables as follows:

         (1) If requireExplicitPolicy is present and has value r, the
         explicit policy state variable is set to the minimum of (a) its
         current value and (b) the sum of r and i (the current
         certificate in the sequence).

         (2) If inhibitPolicyMapping is present and has value q, the
         policy mapping state variable is set to the minimum of (a) its
         current value and (b) the sum of q and i (the current
         certificate in the sequence).

   If any one of the above checks fail, the procedure terminates,
   returning a failure indication and an appropriate reason.  If none of
   the above checks fail on the end-entity certificate, the procedure
   terminates, returning a success indication together with the set of
   all policy qualifier values encountered in the set of certificates.

   Notes:  It is possible to specify an extended version of the above
   certification path processing procedure which results in default
   behaviour identical to the rules of Privacy Enhanced Mail [RFC 1422].
   In this extended version, additional inputs to the procedure are a
   list of one or more Policy Certification Authoritys (PCAs) names and
   an indicator of the position in the certification path where the PCA
   is expected.  At the nominated PCA position, the CA name is compared
   against this list.  If a recognized PCA name is found, then a
   constraint of SubordinateToCA is implicitly assumed for the remainder
   of the certification path and processing continues.  If no valid PCA
   name is found, and if the certification path cannot be validated on
   the basis of identified policies, then the certification path is
   considered invalid.




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   This procedure may also be extended by providing a set of self-signed
   certificates to the validation module.  In this case, a valid path
   could begin with any one of the self-signed certificates.  These
   self-signed certificates permit the path validation module to
   automatically incorporate local security policy and requirements.

7  Algorithm Support

   This section describes cryptographic algorithms which may be used
   with this standard.  The section describes one-way hash functions and
   digital signature algorithms which may be used to sign certificates
   and CRLs, and identifies object identifiers for public keys contained
   in a certificate.

   Conforming CAs and applications are not required to support the
   algorithms or algorithm identifiers described in this section.
   However, this profile requires conforming CAs and applications to
   conform when they use the algorithms identified here.

7.1  One-way Hash Functions

   This section identifies one-way hash functions for use in the
   Internet PKI.  One-way hash functions are also called message digest
   algorithms. SHA-1 is the preferred one-way hash function for the
   Internet PKI.  However, PEM uses MD2 for certificates [RFC 1422] [RFC
   1423] and MD5 is used in other legacy applications.  For this reason,
   MD2 and MD5 are included in this profile.

7.1.1  MD2 One-way Hash Function

   MD2 was developed by Ron Rivest, but RSA Data Security has not placed
   the MD2 algorithm in the public domain.  Rather, RSA Data Security
   has granted license to use MD2 for non-commercial Internet Privacy-
   Enhanced Mail.  For this reason, MD2 may continue to be used with PEM
   certificates, but SHA-1 is preferred.  MD2 is fully described in RFC
   1319 [RFC 1319].

   At the Selected Areas in Cryptography '95 conference in May 1995,
   Rogier and Chauvaud presented an attack on MD2 that can nearly find
   collisions [RC95].  Collisions occur when one can find two different
   messages that generate the same message digest.  A checksum operation
   in MD2 is the only remaining obstacle to the success of the attack.
   For this reason, the use of MD2 for new applications is discouraged.
   It is still reasonable to use MD2 to verify existing signatures, as
   the ability to find collisions in MD2 does not enable an attacker to
   find new messages having a previously computed hash value.

   << More information on the attack and its implications can be



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   obtained from a RSA Laboratories security bulletin.  These bulletins
   are available from <http://www.rsa.com/>. >>

7.1.2  MD5 One-way Hash Function

   MD5 was developed by Ron Rivest in 1991.  The algorithm takes as
   input a message of arbitrary length and produces as output a 128-bit
   "fingerprint" or "message digest" of the input.  The MD5 message
   digest algorithm is specified by RFC 1321, "The MD5 Message-Digest
   Algorithm"[RFC1321].

   Den Boer and Bosselaers [DB94] have found pseudo-collisions for MD5,
   but there are no other known cryptanalytic results.  The use of MD5
   for new applications is discouraged.  It is still reasonable to use
   MD5 to verify existing signatures.

7.1.2  SHA-1 One-way Hash Function

   SHA-1 was developed by the U.S. Government.  The algorithm takes as
   input a message of arbitrary length and produces as output a 160-bit
   "hash" of the input.  SHA-1 is fully described in FIPS 180-1 [FIPS
   180-1].

   SHA-1 is the one-way hash function of choice for use with both the
   RSA and DSA signature algorithms (see Section 7.2).

7.2  Signature Algorithms

   Certificates and CRLs described by this standard may be signed with
   any public key signature algorithm.  The certificate or CRL indicates
   the algorithm through an algorithmidentifier which appears in the
   signatureAlgorithm field in a Certificate or CertificateList.  This
   algorithmidentfier is an OID and has optionally associated
   parameters.  This section identifies algorithm identifiers and
   parameters that shall be used in the signatureAlgorithm field in a
   Certificate or CertificateList.

   RSA and DSA are the most popular signature algorithms used in the
   Internet.  Signature algorithms are always used in conjunction with a
   one-way hash function identified in Section 7.1.

   The signature algorithm (and one-way hash function) used to sign a
   certificate or CRL is indicated by use of an algorithm identifier.
   An algorithm identifier is an object identifier, and may include
   associated parameters.  This section identifies OIDS for RSA and DSA
   and the corresponding parameters.

   The data to be signed (e.g., the one-way hash function output value)



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   is formatted for the signature algorithm to be used.  Then, a private
   key operation (e.g., RSA encryption) is performed to generate the
   signature value.  This signature value is then ASN.1 encoded as a BIT
   STRING and included in the Certificate or CertificateList (in the
   signature field).

7.2.1  RSA Signature Algorithm

   A patent statement regarding the RSA algorithm can be found at the
   end of this profile.

   The RSA algorithm is named for its inventors: Rivest, Shamir, and
   Adleman.  This profile includes three signature algorithms based on
   the RSA asymmetric encryption algorithm. The signature algorithms
   combine RSA with either the MD2, MD5, or the SHA-1 one-way hash
   functions.

   The signature algorithm with MD2 and the RSA encryption algorithm is
   defined in PKCS #1 [PKCS#1].  As defined in PKCS #1, the ASN.1 object
   identifier used to identify this signature algorithm is:

        md2WithRSAEncryption OBJECT IDENTIFIER  ::=  {
            iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
            pkcs-1(1) 2  }

   The signature algorithm with MD5 and the RSA encryption algorithm is
   defined in PKCS #1 [PKCS#1].  As defined in PKCS #1, the ASN.1 object
   identifier used to identify this signature algorithm is:

        md5WithRSAEncryption OBJECT IDENTIFIER  ::=  {
            iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
            pkcs-1(1) 4  }

   The signature algorithm with SHA-1 and the RSA encryption algorithm
   is defined in by the OSI Interoperability Workshop in [OIW]. Padding
   conventions described in PKCS #1, section 8.1, must be used.  As
   defined in [OIW], the ASN.1 object identifier used to identify this
   signature algorithm is:

        sha1WithRSASignature OBJECT IDENTIFIER  ::=  {
            iso(1) identified-organization(3) oiw(14)
            secsig(3) algorithm(2) 29  }

   When any of these three object identifiers appears within the ASN.1
   type AlgorithmIdentifier, the parameters component of that type shall
   be the ASN.1 type NULL.

   The data to be signed (e.g., the one-way hash function output value)



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   is first ASN.1 encoded as an OCTET STRING and the result is encrypted
   (e.g., using RSA Encryption) to form the signed quantity. When
   signing, the RSA algorithm generates an integer y. This signature
   value is then ASN.1 encoded as a BIT STRING, such that the most
   significant bit in y is the first bit in the bit string and the least
   significant bit in y is the last bit in the bit string, and included
   in the Certificate or CertificateList (in the signature field).

   (In general the conversion to a bit string occurs in two steps.  The
   integer y is converted to an octet string such that the first octet
   has the most significance and the last octet has the least
   significance. The octet string is converted into a bit string such
   that the most significant bit of the first octet shall become the
   first bit in the bit string, and the least significant bit of the
   last octet is the last bit in the BIT STRING.)

7.2.2  DSA Signature Algorithm

   A patent statement regarding the DSA can be found at the end of this
   profile.

   The Digital Signature Algorithm (DSA) is also called the Digital
   Signature Standard (DSS).  DSA was developed by the U.S. Government,
   and DSA is used in conjunction with the the SHA-1 one-way hash
   function.  DSA is fully described in FIPS 186 [FIPS 186].  The ASN.1
   object identifiers used to identify this signature algorithm are:

           id-dsa-with-sha1 ID  ::=  {
                   iso(1) member-body(2) us(840) x9-57 (10040)
                   x9cm(4) 3 }

   The id-dsa-with-sha1 algorithm syntax has NULL parameters. The DSA
   parameters in the subjectPublicKeyInfo field of the certificate of
   the issuer shall apply to the verification of the signature.

   If the subjectPublicKeyInfo AlgorithmIdentifier field has NULL
   parameters and the CA signed the subject certificate using DSA, then
   the certificate issuer's parameters apply to the subject's DSA key.
   If the subjectPublicKeyInfo AlgorithmIdentifier field has NULL
   parameters and the CA signed the subject with a signature algorithm
   other than DSA, then clients shall not validate the certificate.

   When signing, the DSA algorithm generates two values.  These values
   are commonly referred to as r and s.  To easily transfer these two
   values as one signature, they shall be ASN.1 encoded using the
   following ASN.1 structure:

           Dss-Sig-Value  ::=  SEQUENCE  {



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                   r       INTEGER,
                   s       INTEGER  }

7.3  Subject Public Key Algorithms

   Certificates described by this standard may convey a public key for
   any public key algorithm. The certificate indicates the algorithm
   through an algorithmidentifier.  This algorithm identfieier is an OID
   and optionally associated parameters.

   This section identifies preferred OIDs and parameters for the RSA,
   DSA, and Diffie-Hellman algorithms.  Conforming CAs shall use the
   identified OIDs when issuing certificates containing public keys for
   these algorithms. Conforming applications supporting any of these
   algorithms shall, at a minimum, recognize the OID identified in this
   section.

7.3.1 RSA  Keys

   The object identifier rsaEncryption identifies RSA public keys.

        pkcs-1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
                       rsadsi(113549) pkcs(1) 1 }

        rsaEncryption OBJECT IDENTIFIER ::=  { pkcs-1 1}

   The rsaEncryption object identifier is intended to be used in the
   algorithm field of a value of type AlgorithmIdentifier. The
   parameters field shall have ASN.1 type NULL for this algorithm
   identifier.

   The rsa public key shall be encoded using the ASN.1 type
   RSAPublicKey:

      RSAPublicKey ::= SEQUENCE {
         modulus       INTEGER, -- n
         publicExponent     INTEGER  -- e
                             }

   where modulus is the modulus n, and publicExponent is the public
   exponent e.  The DER encoded RSAPublicKey is  the value of the BIT
   STRING subjectPubliKey.

   This object identifier is used in public key certificates for both
   RSA signature keys and RSA encryption keys. The intended application
   for the key may be indicated in the key usage field (see Section
   4.2.1.3).  The use of a single key for both signature and encryption
   purposes is not recommended, but is not forbidden.



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   If the keyUsage extension is present in an end entity certificate
   which conveys an RSA public key, any combination of the following
   values may be present:

      digitalSignature;
      nonRepudiation;
      keyEncipherment; and
      dataEncipherment.

   If the keyUsage extension is present in a CA certificate which
   conveys an RSA public key, any combination of the following values
   may be present:

      digitalSignature;
      nonRepudiation;
      keyEncipherment;
      dataEncipherment;
      keyCertSign; and
      cRLSign.
   However, this specification recommends that if keyCertSign or cRLSign
   is present, both keyEncipherment and dataEncipherment should not be
   present.

7.3.2 Diffie-Hellman Key Exchange Key

   This diffie-hellman object identifier supported by this standard is
   defined by ANSI X9.42.

        dhpublicnumber OBJECT IDENTIFIER ::= { iso(1) member-body(2)
                  us(840) ansi-x942(10046) number-type(2) 1 }

   The dhpublicnumber object identifier is intended to be used in the
   algorithm field of a value of type AlgorithmIdentifier. The
   parameters field of that type, which has the algorithm-specific
   syntax ANY DEFINED BY algorithm, would have ASN.1 type DHParameter
   for this algorithm.

        DHParameter ::= SEQUENCE {
          prime INTEGER, -- p
          base INTEGER, -- g }

   The fields of type DHParameter have the following meanings:

      prime is the prime p.

      base is the base g.

   The Diffie-Hellman public key (an INTEGER) is mapped to a



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   subjectPublicKey (a BIT STRING) as follows: the most significant bit
   (MSB) of the INTEGER becomes the MSB of the BIT STRING; the least
   significant bit (LSB) of the INTEGER becomes the LSB of the BIT
   STRING.

   If the keyUsage extension is present in a certificate which conveys a
   DH public key, the following values may be present:

      keyAgreement;
      encipherOnly; and
      decipherOnly.

   At most one of encipherOnly and decipherOnly shall be asserted in
   keyUsage extension.

7.3.3 DSA Signature Keys

   The object identifier supported by this standard is

        id-dsa ID ::= { iso(1) member-body(2) us(840) x9-57(10040)
                  x9cm(4) 1 }

   The id-dsa algorithm syntax includes optional parameters.  These
   parameters are commonly referred to as p, q, and g.  If the DSA
   algorithm parameters are absent from the subjectPublicKeyInfo
   AlgorithmIdentifier and the CA signed the subject certificate using
   DSA, then the certificate issuer's DSA parameters apply to the
   subject's DSA key.  If the DSA algorithm parameters are absent from
   the subjectPublicKeyInfo AlgorithmIdentifier and the CA signed the
   subject certificate using a signature algorithm other than DSA, then
   the subject's DSA parameters are distributed by other means.  The
   parameters are included using the following ASN.1 structure:

        Dss-Parms  ::=  SEQUENCE  {
            p             INTEGER,
            q             INTEGER,
            g             INTEGER  }

   If the subjectPublicKeyInfo AlgorithmIdentifier field has NULL
   parameters and the CA signed the subject certificate using DSA, then
   the certificate issuer's parameters apply to the subject's DSA key.
   If the subjectPublicKeyInfo AlgorithmIdentifier field has NULL
   parameters and the CA signed the subject with a signature algorithm
   other than DSA, then clients shall not validate the certificate.

   When signing, DSA algorithm generates two values.  These values are
   commonly referred to as r and s.  To easily transfer these two values
   as one signature, they are ASN.1 encoded using the following ASN.1



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   structure:

        Dss-Sig-Value  ::=  SEQUENCE  {
            r             INTEGER,
            s             INTEGER  }

   The encoded signature is conveyed as the value of the BIT STRING
   signature in a Certificate or CertificateList.

   The DSA public key shall be ASN.1 encoded as an INTEGER; this
   encoding shall be used as the contents (i.e., the value) of the
   subjectPublicKey component (a BIT STRING) of the SubjectPublicKeyInfo
   data element.

        DSAPublicKey ::= INTEGER -- public key Y


   If the keyUsage extension is present in an end entity certificate
   which conveys a DSA public key, any combination of the following
   values may be present:

      digitalSignature; and
      nonRepudiation.

   If the keyUsage extension is present in an CA certificate which
   conveys a DSA public key, any combination of the following values may
   be present:

      digitalSignature;
      nonRepudiation;
      keyCertSign; and
      cRLSign.

References

   [COR95]  ISO/IEC JTC 1/SC 21, Technical Corrigendum 2 to ISO/IEC
            9594-8: 1990 & 1993 (1995:E), July 1995.

   [FIPS 180-1]  Federal Information Processing Standards Publication
            (FIPS PUB) 180-1, Secure Hash Standard, 17 April 1995.
            [Supersedes FIPS PUB 180 dated 11 May 1993.]

   [FIPS 186] Federal Information Processing Standards Publication
            (FIPS PUB) 186, Digital Signature Standard, 18 May 1994.

   [OIW]    Stable Implementation Agreements for Open Systems
            Interconnection Protocols: Part 12 - OS Security,
            Output  from the June 1995 Open Systems Environment



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            Implementors' Workshop (OIW).

   [PKCS#1] PKCS #1: RSA Encryption Standard, Version 1.4, RSA Data
            Security, Inc., 3 June 1991.

   [RC95]   Rogier, N. and Chauvaud, P., "The compression function of
            MD2 is not collision free," Presented at Selected Areas in
            Cryptography '95, Carleton University, Ottawa, Canada,
            18-19 May 1995.

   [RFC 791] J. Postel, "Internet Protocol", September 1981.

   [RFC 1319] Kaliski, B., "The MD2 Message-Digest Algorithm," RFC 1319,
            RSA Laboratories, April 1992.

   [RFC 1422] Kent, S.,  "Privacy Enhancement for Internet Electronic
            Mail: Part II: Certificate-Based Key Management," RFC
            1422, BBN Communications, February 1993.

   [RFC 1423] Balenson, D., "Privacy Enhancement for Internet Electronic
            Mail: Part III: Algorithms, Modes, and Identifiers,"
            RFC 1423, Trusted Information Systems, February 1993.

   [RFC 1738] T. Berners-Lee, L. Masinter & M. McCahill, "Uniform
              Resource Locators (URL)," December 1994.

   [RFC 1777] W. Yeong, T. Howes & S. Kille, "Lightweight Directory
              Access Protocol," March 1995.

   [RFC 1778] T. Howes, S. Kille, W. Yeong, C. Robbins, "The String
            Representation of Standard Attribute Syntaxes", March 1995.

   [RFC 1883] S. Deering, R.  Hinden, "Internet Protocol, Version 6
            (IPv6)," December 1995.

   [RFC 1959] T. Howes, M. Smith, "An LDAP URL Format", RFC 1959,
            June 1996.

   [PKIXMGMT] C. Adams, S. Farrell, "Internet Public Key Infrastructure
            Certificate Management Protocols",
            draft-ietf-pkix-ipki3cmp-04.txt, September 1997

   [PKIXLDAP] S. Boyeun, T. Howes and P. Richard "Internet Public Key
            Infrastructure Operational Protocols - LDAP",
            draft-ietf-pkix-ipki2opp-03.txt, September 1997.

   [PKIXOCSP] M. Myers, in "Internet Public Key Infrastructure Part 2:
            Operational Protocols", draft-ietf-pkix-ipki2opp-02.txt,



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            July 1997.

   [PKIXFTP] R. Housley, "Internet Public Key Infrastructure Operational
            Protocols:  FTP and HTTP", draft-ietf-pkix-opp-ftp-http-00.txt,
            September 1997.

   [SDN.701R] SDN.701, "Message Security Protocol", Revision 4.0
            1996-06-07 with "Corrections to Message Security Protocol,
            SDN.701, Rev 4.0, 96-06-07." August 30, 1996.

   [X.208]  CCITT Recommendation X.208: Specification of Abstract
              Syntax Notation One (ASN.1), 1988.

   [X.509-AM] ISO/IEC JTC1/SC 21, Draft Amendments DAM 4 to ISO/IEC
            9594-2, DAM 2 to ISO/IEC 9594-6, DAM 1 to ISO/IEC 9594-7,
              and DAM 1 to ISO/IEC 9594-8 on Certificate Extensions,
              1 December, 1996.

   [X9.55]  ANSI X9.55-1995, Public Key Cryptography For The Financial
              Services Industry: Extensions To Public Key Certificates
              And Certificate Revocation Lists, 8 December, 1995.

   [X9.57]  ANSI X9.57-199x, Public Key Cryptography For The Financial
              Services Industry: Certificate Management (Working Draft),
              21 June, 1996.

Patent Statements

   The Internet PKI relies on the use of patented public key technology
   and secure hash technology for digital signature services.  This
   specification also references public key encryption technology for
   provisioning key exchange services.

   The Internet Standards Process as defined in RFC 1310 requires a
   written statement from the Patent holder that a license will be made
   available to applicants under reasonable terms and conditions prior
   to approving a specification as a Proposed, Draft or Internet
   Standard.

   Patent statements for DSA, RSA, and Diffie-Hellman follow.  These
   statements have been supplied by the patent holders, not the authors
   of this profile.

   The Internet Society, Internet Architecture Board, Internet
   Engineering Steering Group and the Corporation for National Research
   Initiatives take no position on the validity or scope of the
   following patents and patent applications, nor on the appropriateness
   of the terms of the assurance. The Internet Society and other groups



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   mentioned above have not made any determination as to any other
   intellectual property rights which may apply to the practice of this
   standard.  Any further consideration of these matters is the user's
   own responsibility.

   Digital Signature Algorithm (DSA)

      The U.S. Government holds patent 5,231,668 on the Digital
      Signature Algorithm (DSA), which has been incorporated into
      Federal Information Processing Standard (FIPS) 186.  The patent
      was issued on July 27, 1993.

      The National Institute of Standards and Technology (NIST) has a
      long tradition of supplying U.S. Government-developed techniques
      to committees and working groups for inclusion into standards on a
      royalty-free basis.  NIST has made the DSA patent available
      royalty-free to users worldwide.

      Regarding patent infringement, FIPS 186 summarizes our position;
      the Department of Commerce is not aware of any patents that would
      be infringed by the DSA.  Questions regarding this matter may be
      directed to the Deputy Chief Counsel for NIST.

   RSA Signature and Encryption

      The Massachusetts Institute of Technology has granted RSA Data
      Security, Inc., exclusive sub-licensing rights to the following
      patent issued in the United States:

      Cryptographic Communications System and Method ("RSA"), No.
      4,405,829

      RSA Data Security, Inc. has provided the following statement with
      regard to this patent:

         It is our understanding that the proposed PKIX Certificate
         Profile (PKIX-1) standard currently under review contemplates
         the use of U.S Patent 4,405,829 entitled "Cryptographic
         Communication System and Method" (the "RSA patent") which
         patent is controlled by RSA.

         It is RSA's business practice to make licenses to its patents
         available on reasonable and nondiscriminatory terms.
         Accordingly, if the foregoing identified IETF standard is
         adopted, RSA is willing, upon request, to grant non-exclusive
         licenses to such patent on reasonable and non-discriminatory
         terms and conditions to those who respect RSA's intellectual
         property rights and subject to RSA's then current royalty rate



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         for the patent licensed. The royalty rate for the RSA patent is
         presently set at 2% of the licensee's selling price for each
         product covered by the patent. Any requests for license
         information may be directed to:

            Director of Licensing RSA Data Security, Inc.  100 Marine
            Parkway, Suite 500 Redwood City, CA 94065

         A license under RSA's patent(s) does not include any rights to
         know-how or other technical information or license under other
         intellectual property rights.  Such license does not extend to
         any activities which constitute infringement or inducement
         thereto. A licensee must make his own determination as to
         whether a license is necessary under patents of others.

   Diffie-Hellman Key Agreement and Hellman-Merkle Public Key
   Cryptography

   Patent No. 4,200,770: Cryptographic Apparatus and Method ("Diffie-
   Hellman") expired on August 19, 1997.  Patent No. 4,218,582: Public
   Key Cryptographic Apparatus and Method ("Hellman-Merkle") expired on
   April 29, 1997.

Appendix A. ASN.1 Structures and OIDs


PKIX1 DEFINITIONS IMPLICIT TAGS::=

BEGIN

-- UNIVERSAL Types defined in '93 ASN.1
-- but required by this specification

UniversalString ::= [UNIVERSAL 28] IMPLICIT OCTET STRING
        -- UniversalString is defined in ASN.1:1993

BMPString ::= [UNIVERSAL 30] IMPLICIT OCTET STRING
        -- BMPString is the subtype of
        -- UniversalString and models the Basic Multilingual Plane
        -- of ISO/IEC 10646-1
--
-- Proposed PKIX OIDs
id-pkix  OBJECT IDENTIFIER  ::=
         { iso(1) identified-organization(3) dod(6) internet(1)
                    security(5) mechanisms(5) pkix(7) }

-- PKIX arcs
-- arc for private certificate extensions



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id-pe OBJECT IDENTIFIER  ::=  { id-pkix 1 }
 -- arc for policy qualifier types
id-qt OBJECT IDENTIFIER ::= { id-pkix 2 }
-- arc for extended key purpose OIDS
id-kp OBJECT IDENTIFIER ::= { id-pkix 3 }
-- arc for access descriptors
id-ad OBJECT IDENTIFIER ::= { id-pkix 48 }

-- pkix private extensions
id-pe-authorityInfoAccess OBJECT IDENTIFIER ::= { id-pe 1 }

-- policyQualifierIds for Internet policy qualifiers
id-qt-cps      OBJECT IDENTIFIER ::=  { id-qt 1 }
id-qt-unotice  OBJECT IDENTIFIER ::=  { id-qt 2 }

-- extended key purpose OIDs
id-kp-serverAuth      OBJECT IDENTIFIER ::= { id-kp 1 }
id-kp-clientAuth      OBJECT IDENTIFIER ::= { id-kp 2 }
id-kp-codeSigning     OBJECT IDENTIFIER ::= { id-kp 3 }
id-kp-emailProtection OBJECT IDENTIFIER ::= { id-kp 4 }
id-kp-ipsecEndSystem  OBJECT IDENTIFIER ::= { id-kp 5 }
id-kp-ipsecTunnel     OBJECT IDENTIFIER ::= { id-kp 6 }
id-kp-ipsecUser       OBJECT IDENTIFIER ::= { id-kp 7 }
id-kp-timeStamping    OBJECT IDENTIFIER ::= { id-kp 8 }

-- access descriptors for authority info access extension
id-ad-ocsp      OBJECT IDENTIFIER ::= { id-ad 1 }
id-ad-caIssuers OBJECT IDENTIFIER ::= { id-ad 2 }

-- attribute data types --

Attribute       ::=     SEQUENCE {
        type    AttributeValue,
        values  SET OF AttributeValue
                -- at least one value is required -- }

AttributeType           ::=   OBJECT IDENTIFIER

AttributeValue          ::=   ANY

AttributeTypeAndValue           ::=     SEQUENCE {
        type    AttributeType,
        value   AttributeValue }

-- naming data types --

Name            ::=   CHOICE { -- only one possibility for now --
                                 rdnSequence  RDNSequence }



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RDNSequence     ::=   SEQUENCE OF RelativeDistinguishedName

DistinguishedName       ::=   RDNSequence

RelativeDistinguishedName  ::=
                        SET SIZE (1 .. MAX) OF AttributeTypeAndValue

-- Directory string type --

DirectoryString ::= CHOICE {
        teletexString           TeletexString (SIZE (1..maxSize)),
        printableString         PrintableString (SIZE (1..maxSize)),
        universalString         UniversalString (SIZE (1..maxSize)),
      bmpString               BMPString (SIZE(1..maxSIZE))
                            }

-- certificate and CRL specific structures begin here

Certificate  ::=  SEQUENCE  {
     tbsCertificate       TBSCertificate,
     signatureAlgorithm   AlgorithmIdentifier,
     signature            BIT STRING  }

TBSCertificate  ::=  SEQUENCE  {
     version         [0]  EXPLICIT Version DEFAULT v1,
     serialNumber         CertificateSerialNumber,
     signature            AlgorithmIdentifier,
     issuer               Name,
     validity             Validity,
     subject              Name,
     subjectPublicKeyInfo SubjectPublicKeyInfo,
     issuerUniqueID  [1]  UniqueIdentifier OPTIONAL,
                          -- If present, version must be v2 or v3
     subjectUniqueID [2]  UniqueIdentifier OPTIONAL,
                          -- If present, version must be v2 or v3
     extensions      [3]  EXPLICIT Extensions OPTIONAL
                          -- If present, version must be v3
     }

Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }

CertificateSerialNumber  ::=  INTEGER

Validity ::= SEQUENCE {
     notBefore      Time,
     notAfter       Time }

Time ::= CHOICE {



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     utcTime        UTCTime,
     generalTime    GeneralizedTime }

UniqueIdentifier  ::=  BIT STRING

SubjectPublicKeyInfo  ::=  SEQUENCE  {
     algorithm            AlgorithmIdentifier,
     subjectPublicKey     BIT STRING  }

Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension

Extension  ::=  SEQUENCE  {
     extnID      OBJECT IDENTIFIER,
     critical    BOOLEAN DEFAULT FALSE,
     extnValue   OCTET STRING  }

-- Extension ::= { {id-ce 15}, ... , keyUsage }

ID                         ::=  OBJECT IDENTIFIER
joint-iso-ccitt       ID   ::=  { 2 }
ds                    ID   ::=  {joint-iso-ccitt 5}
id-ce                 ID   ::=  {ds 29}

AuthorityKeyIdentifier ::= SEQUENCE {
      keyIdentifier             [0] KeyIdentifier            OPTIONAL,
      authorityCertIssuer       [1] GeneralNames             OPTIONAL,
      authorityCertSerialNumber [2] CertificateSerialNumber  OPTIONAL
  }
       ( WITH COMPONENTS       {..., authorityCertIssuer PRESENT,
                                  authorityCertSerialNumber PRESENT} |
        WITH COMPONENTS        {..., authorityCertIssuer ABSENT,
                                  authorityCertSerialNumber ABSENT} )

KeyIdentifier ::= OCTET STRING

-- subjectKeyIdentifier ::= KeyIdentifier

KeyUsage ::= BIT STRING {
     digitalSignature        (0),
     nonRepudiation          (1),
     keyEncipherment         (2),
     dataEncipherment        (3),
     keyAgreement            (4),
     keyCertSign             (5),
     cRLSign                 (6) }

id-ce-privateKeyUsagePeriod OBJECT IDENTIFIER ::=  { id-ce 16 }




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PrivateKeyUsagePeriod ::= SEQUENCE {
     notBefore       [0]     GeneralizedTime OPTIONAL,
     notAfter        [1]     GeneralizedTime OPTIONAL }
     ( WITH COMPONENTS       {..., notBefore PRESENT} |
     WITH COMPONENTS         {..., notAfter PRESENT} )

id-ce-certificatePolicies OBJECT IDENTIFIER ::=  { id-ce 32 }

CertificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation

PolicyInformation ::= SEQUENCE {
     policyIdentifier   CertPolicyId,
     policyQualifiers   SEQUENCE SIZE (1..MAX) OF
             PolicyQualifierInfo OPTIONAL }

CertPolicyId ::= OBJECT IDENTIFIER

PolicyQualifierInfo ::= SEQUENCE {
       policyQualifierId  PolicyQualifierId,
       qualifier        ANY DEFINED BY policyQualifierId }

PolicyQualifierId ::= OBJECT IDENTIFIER

id-ce-policyMappings OBJECT IDENTIFIER ::=  { id-ce 33 }

PolicyMappings ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE {
     issuerDomainPolicy      CertPolicyId,
     subjectDomainPolicy     CertPolicyId }

id-ce-subjectAltName OBJECT IDENTIFIER ::=  { id-ce 17 }

SubjectAltName ::= GeneralNames

GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName

GeneralName ::= CHOICE {
-- OTHER-NAME ::= TYPE-IDENTIFIER  note: not supported in '88 ASN.1
     otherName                       [0]     AnotherName,
     rfc822Name                      [1]     IA5String,
     dNSName                         [2]     IA5String,
     x400Address                     [3]     ORAddress,
     directoryName                   [4]     Name,
     ediPartyName                    [5]     EDIPartyName,
     uniformResourceIdentifier       [6]     IA5String,
     iPAddress                       [7]     OCTET STRING,
     registeredID                    [8]     OBJECT IDENTIFIER }

AnotherName ::= SEQUENCE {



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     type-id    OBJECT IDENTIFIER,
     value      [0] EXPLICIT ANY DEFINED BY type-id
     }

EDIPartyName ::= SEQUENCE {
     nameAssigner            [0]     DirectoryString OPTIONAL,
     partyName               [1]     DirectoryString }

id-ce-issuerAltName OBJECT IDENTIFIER ::=  { id-ce 18 }

IssuerAltName ::= GeneralNames

id-ce-subjectDirectoryAttributes OBJECT IDENTIFIER ::=  { id-ce 9 }

SubjectDirectoryAttributes ::= SEQUENCE SIZE (1..MAX) OF Attribute

id-ce-basicConstraints OBJECT IDENTIFIER ::=  { id-ce 19 }

BasicConstraints ::= SEQUENCE {
     cA                      BOOLEAN DEFAULT FALSE,
     pathLenConstraint       INTEGER (0..MAX) OPTIONAL }

id-ce-nameConstraints OBJECT IDENTIFIER ::=  { id-ce 30 }

NameConstraints ::= SEQUENCE {
     permittedSubtrees       [0]     GeneralSubtrees OPTIONAL,
     excludedSubtrees        [1]     GeneralSubtrees OPTIONAL }

GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree

GeneralSubtree ::= SEQUENCE {
     base                    GeneralName,
     minimum         [0]     BaseDistance DEFAULT 0,
     maximum         [1]     BaseDistance OPTIONAL }

BaseDistance ::= INTEGER (0..MAX)

id-ce-policyConstraints OBJECT IDENTIFIER ::=  { id-ce 36 }

PolicyConstraints ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE {
     requireExplicitPolicy           [0] SkipCerts OPTIONAL,
     inhibitPolicyMapping            [1] SkipCerts OPTIONAL }

SkipCerts ::= INTEGER (0..MAX)

-- cRLDistributionPoints CRLDistPointsSyntax ::=
--              SEQUENCE SIZE (1..MAX) OF DistributionPoint




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CRLDistPointsSyntax ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint

DistributionPoint ::= SEQUENCE {
     distributionPoint       [0]     DistributionPointName OPTIONAL,
     reasons                 [1]     ReasonFlags OPTIONAL,
     cRLIssuer               [2]     GeneralNames OPTIONAL }

DistributionPointName ::= CHOICE {
     fullName                [0]     GeneralNames,
     nameRelativeToCRLIssuer [1]     RelativeDistinguishedName }

ReasonFlags ::= BIT STRING {
     unused                  (0),
     keyCompromise           (1),
     cACompromise            (2),
     affiliationChanged      (3),
     superseded              (4),
     cessationOfOperation    (5),
     certificateHold         (6) }

id-ce-extKeyUsage OBJECT IDENTIFIER ::= {id-ce 37}

ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId

KeyPurposeId ::= OBJECT IDENTIFIER

AuthorityInfoAccessSyntax  ::=
        SEQUENCE SIZE (1..MAX) OF AccessDescription

AccessDescription  ::=  SEQUENCE {
        accessMethod          OBJECT IDENTIFIER,
        accessLocation        GeneralName  }

-- CRL structures

CertificateList  ::=  SEQUENCE  {
     tbsCertList          TBSCertList,
     signatureAlgorithm   AlgorithmIdentifier,
     signature            BIT STRING  }

TBSCertList  ::=  SEQUENCE  {
     version                 Version OPTIONAL,
                                  -- if present, must be v2
     signature               AlgorithmIdentifier,
     issuer                  Name,
     thisUpdate              Time,
     nextUpdate              Time  OPTIONAL,
     revokedCertificates     SEQUENCE OF SEQUENCE  {



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          userCertificate         CertificateSerialNumber,
          revocationDate          Time,
          crlEntryExtensions      Extensions OPTIONAL
                                         -- if present, must be v2
                               }  OPTIONAL,
     crlExtensions           [0]  EXPLICIT Extensions OPTIONAL
                                         -- if present, must be v2
                               }

-- Version, Time, CertificateSerialNumber, and Extensions were
-- defined earlier for use in the certificate structure

AlgorithmIdentifier  ::=  SEQUENCE  {
     algorithm               OBJECT IDENTIFIER,
     parameters              ANY DEFINED BY algorithm OPTIONAL  }
                                -- contains a value of the type
                                -- registered for use with the
                                -- algorithm object identifier value


id-ce-cRLNumber OBJECT IDENTIFIER ::= { id-ce 20 }

CRLNumber ::= INTEGER (0..MAX)

id-ce-issuingDistributionPoint OBJECT IDENTIFIER ::= { id-ce 28 }

IssuingDistributionPoint ::= SEQUENCE {
     distributionPoint       [0] DistributionPointName OPTIONAL,
     onlyContainsUserCerts   [1] BOOLEAN DEFAULT FALSE,
     onlyContainsCACerts     [2] BOOLEAN DEFAULT FALSE,
     onlySomeReasons         [3] ReasonFlags OPTIONAL,
     indirectCRL             [4] BOOLEAN DEFAULT FALSE }


id-ce-deltaCRLIndicator OBJECT IDENTIFIER ::= { id-ce 27 }

-- deltaCRLIndicator ::= BaseCRLNumber

id-ce-cRLNumber OBJECT IDENTIFIER ::= { id-ce 20 }

BaseCRLNumber ::= CRLNumber

id-ce-cRLReasons OBJECT IDENTIFIER ::= { id-ce 21 }

CRLReason ::= ENUMERATED {
     unspecified             (0),
     keyCompromise           (1),
     cACompromise            (2),



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     affiliationChanged      (3),
     superseded              (4),
     cessationOfOperation    (5),
     certificateHold         (6),
     removeFromCRL           (8) }

id-ce-certificateIssuer OBJECT IDENTIFIER ::= { id-ce 29 }

CertificateIssuer ::= GeneralNames

id-ce-holdInstructionCode OBJECT IDENTIFIER ::= { id-ce 23 }

HoldInstructionCode ::= OBJECT IDENTIFIER

-- ANSI x9 arc holdinstruction arc

member-body ID ::= { iso 2 }
us ID ::= { member-body 840 }
x9cm ID ::= { us 10040 }
holdInstruction ID ::= {x9cm 2}

-- ANSI X9 holdinstructions referenced by this standard

id-holdinstruction-none ID ::= {holdInstruction 1}
id-holdinstruction-callissuer ID ::= {holdInstruction 2}
id-holdinstruction-reject ID ::= {holdInstruction 3}

id-ce-invalidityDate OBJECT IDENTIFIER ::= { id-ce 24 }

InvalidityDate ::=  GeneralizedTime

-- Algorithm structures

     md2WithRSAEncryption OBJECT IDENTIFIER  ::=  {
         iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
         pkcs-1(1) 2  }

     md5WithRSAEncryption OBJECT IDENTIFIER  ::=  {
         iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
         pkcs-1(1) 4  }

     sha1WithRSASignature OBJECT IDENTIFIER  ::=  {
         iso(1) identified-organization(3) oiw(14) secsig(3)
         algorithm(2) 29  }

     id-dsa-with-sha1 ID  ::=  {
                iso(1) member-body(2) us(840) x9-57 (10040)
                x9algorithm(4) 3 }



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     Dss-Sig-Value  ::=  SEQUENCE  {
                r       INTEGER,
                s       INTEGER  }

     pkcs-1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
                    rsadsi(113549) pkcs(1) 1 }

     rsaEncryption OBJECT IDENTIFIER ::=  { pkcs-1 1}

     dhpublicnumber OBJECT IDENTIFIER ::= { iso(1) member-body(2)
               us(840) ansi-x942(10046) number-type(2) 1 }

     DHParameter ::= SEQUENCE {
          prime INTEGER, -- p
          base INTEGER -- g
                }

     id-dsa ID ::= { iso(1) member-body(2) us(840) x9-57(10040)
                x9algorithm(4) 1 }

     Dss-Parms  ::=  SEQUENCE  {
         p             INTEGER,
         q             INTEGER,
         g             INTEGER  }

     id-keyEncryptionAlgorithm  OBJECT IDENTIFIER   ::=
          { 2 16 840 1 101 2 1 1 22 }

     KEA-Parms-Id     ::= OCTET STRING

id-ce-subjectKeyIdentifier OBJECT IDENTIFIER ::=  { id-ce 14 }
id-ce-keyUsage OBJECT IDENTIFIER ::=  { id-ce 15 }
id-ce-authorityKeyIdentifier OBJECT IDENTIFIER ::=  { id-ce 35 }

CPSuri ::= IA5String

UserNotice ::= CHOICE {
  visibleString     VisibleString,
  bmpString         BMPString
                      }

PresentationAddress ::= SEQUENCE {
        pSelector       [0] EXPLICIT OCTET STRING OPTIONAL,
        sSelector       [1] EXPLICIT OCTET STRING OPTIONAL,
        tSelector       [2] EXPLICIT OCTET STRING OPTIONAL,
        nAddresses      [3] EXPLICIT SET SIZE (1..MAX) OF OCTET STRING}

-- x400 address syntax starts here



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--      OR Names

ORAddressAndOrDirectoryName ::= ORName

ORAddressAndOptionalDirectoryName ::= ORName

ORName ::= [APPLICATION 0] SEQUENCE {
   -- address -- COMPONENTS OF ORAddress,
   directory-name [0] Name OPTIONAL }

ORAddress ::= SEQUENCE {
   built-in-standard-attributes BuiltInStandardAttributes,
   built-in-domain-defined-attributes
                        BuiltInDomainDefinedAttributes OPTIONAL,
   -- see also teletex-domain-defined-attributes
   extension-attributes ExtensionAttributes OPTIONAL }
--      The OR-address is semantically absent from the OR-name if the
--      built-in-standard-attribute sequence is empty and the
--      built-in-domain-defined-attributes and extension-attributes are
--      both omitted.

--      Built-in Standard Attributes
BuiltInStandardAttributes ::= SEQUENCE {
   country-name CountryName OPTIONAL,
   administration-domain-name AdministrationDomainName OPTIONAL,
   network-address      [0] NetworkAddress OPTIONAL,
   -- see also extended-network-address
   terminal-identifier  [1] TerminalIdentifier OPTIONAL,
   private-domain-name  [2] PrivateDomainName OPTIONAL,
   organization-name    [3] OrganizationName OPTIONAL,
   -- see also teletex-organization-name
   numeric-user-identifier      [4] NumericUserIdentifier OPTIONAL,
   personal-name        [5] PersonalName OPTIONAL,
   -- see also teletex-personal-name
   organizational-unit-names    [6] OrganizationalUnitNames OPTIONAL
   -- see also teletex-organizational-unit-names -- }

CountryName ::= [APPLICATION 1] CHOICE {
   x121-dcc-code NumericString
                (SIZE (ub-country-name-numeric-length)),
   iso-3166-alpha2-code PrintableString
                (SIZE (ub-country-name-alpha-length)) }

AdministrationDomainName ::= [APPLICATION 2] CHOICE {
   numeric NumericString (SIZE (0..ub-domain-name-length)),
   printable PrintableString (SIZE (0..ub-domain-name-length)) }

NetworkAddress ::= X121Address



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-- see also extended-network-address

X121Address ::= NumericString (SIZE (1..ub-x121-address-length))

TerminalIdentifier ::= PrintableString (SIZE (1..ub-terminal-id-length))

PrivateDomainName ::= CHOICE {
   numeric NumericString (SIZE (1..ub-domain-name-length)),
   printable PrintableString (SIZE (1..ub-domain-name-length)) }

OrganizationName ::= PrintableString
                            (SIZE (1..ub-organization-name-length))
-- see also teletex-organization-name

NumericUserIdentifier ::= NumericString
                            (SIZE (1..ub-numeric-user-id-length))

PersonalName ::= SET {
   surname [0] PrintableString (SIZE (1..ub-surname-length)),
   given-name [1] PrintableString
                        (SIZE (1..ub-given-name-length)) OPTIONAL,
   initials [2] PrintableString (SIZE (1..ub-initials-length)) OPTIONAL,
   generation-qualifier [3] PrintableString
                (SIZE (1..ub-generation-qualifier-length)) OPTIONAL}
-- see also teletex-personal-name

OrganizationalUnitNames ::= SEQUENCE SIZE (1..ub-organizational-units)
                                        OF OrganizationalUnitName
-- see also teletex-organizational-unit-names

OrganizationalUnitName ::= PrintableString (SIZE
                        (1..ub-organizational-unit-name-length))

--      Built-in Domain-defined Attributes
BuiltInDomainDefinedAttributes ::= SEQUENCE SIZE
                                (1..ub-domain-defined-attributes) OF
                                BuiltInDomainDefinedAttribute

BuiltInDomainDefinedAttribute ::= SEQUENCE {
   type PrintableString (SIZE
                        (1..ub-domain-defined-attribute-type-length)),
   value PrintableString (SIZE
                        (1..ub-domain-defined-attribute-value-length))}

--      Extension Attributes
ExtensionAttributes ::= SET SIZE (1..ub-extension-attributes) OF
                        ExtensionAttribute
ExtensionAttribute ::= EXTENSION-ATTRIBUTE



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EXTENSION-ATTRIBUTE ::= SEQUENCE {
   extension-attribute-type [0] INTEGER (0..ub-extension-attributes),
   extension-attribute-value [1] ANY DEFINED BY extension-attribute-type
                                }

extensionAttributeTable EXTENSION-ATTRIBUTE ::= {
   common-name |
   teletex-common-name |
   teletex-organization-name |
   teletex-personal-name |
   teletex-organizational-unit-names |
   teletex-domain-defined-attributes |
   pds-name |
   physical-delivery-country-name |
   postal-code |
   physical-delivery-office-name |
   physical-delivery-office-number |
   extension-OR-address-components |
   physical-delivery-personal-name |
   physical-delivery-organization-name |
   extension-physical-delivery-address-components |
   unformatted-postal-address |
   street-address |
   post-office-box-address |
   poste-restante-address |
   unique-postal-name |
   local-postal-attributes |
   extended-network-address |
   terminal-type }

--      Extension Standard Attributes

common-name EXTENSION-ATTRIBUTE ::= {CommonName IDENTIFIED BY 1}

CommonName ::= PrintableString (SIZE (1..ub-common-name-length))

teletex-common-name EXTENSION-ATTRIBUTE ::=
                {TeletexCommonName IDENTIFIED BY 2}

TeletexCommonName ::= TeletexString (SIZE (1..ub-common-name-length))

teletex-organization-name EXTENSION-ATTRIBUTE ::=
                {TeletexOrganizationName IDENTIFIED BY 3}

TeletexOrganizationName ::=
                TeletexString (SIZE (1..ub-organization-name-length))

teletex-personal-name EXTENSION-ATTRIBUTE ::=



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                {TeletexPersonalName IDENTIFIED BY 4}

TeletexPersonalName ::= SET {
   surname [0] TeletexString (SIZE (1..ub-surname-length)),
   given-name [1] TeletexString
                           (SIZE (1..ub-given-name-length)) OPTIONAL,
   initials [2] TeletexString (SIZE (1..ub-initials-length)) OPTIONAL,
   generation-qualifier [3] TeletexString (SIZE
                        (1..ub-generation-qualifier-length)) OPTIONAL }

teletex-organizational-unit-names EXTENSION-ATTRIBUTE ::=
   {TeletexOrganizationalUnitNames IDENTIFIED BY 5}

TeletexOrganizationalUnitNames ::= SEQUENCE SIZE
        (1..ub-organizational-units) OF TeletexOrganizationalUnitName

TeletexOrganizationalUnitName ::= TeletexString
                        (SIZE (1..ub-organizational-unit-name-length))

pds-name EXTENSION-ATTRIBUTE ::= {PDSName IDENTIFIED BY 7}

PDSName ::= PrintableString (SIZE (1..ub-pds-name-length))

physical-delivery-country-name EXTENSION-ATTRIBUTE ::=
   {PhysicalDeliveryCountryName IDENTIFIED BY 8}

PhysicalDeliveryCountryName ::= CHOICE {
   x121-dcc-code NumericString (SIZE (ub-country-name-numeric-length)),
   iso-3166-alpha2-code PrintableString
                        (SIZE (ub-country-name-alpha-length)) }

postal-code EXTENSION-ATTRIBUTE ::= {PostalCode IDENTIFIED BY 9}

PostalCode ::= CHOICE {
   numeric-code NumericString (SIZE (1..ub-postal-code-length)),
   printable-code PrintableString (SIZE (1..ub-postal-code-length)) }

physical-delivery-office-name EXTENSION-ATTRIBUTE ::=
                        {PhysicalDeliveryOfficeName IDENTIFIED BY 10}

PhysicalDeliveryOfficeName ::= PDSParameter

physical-delivery-office-number EXTENSION-ATTRIBUTE ::=
   {PhysicalDeliveryOfficeNumber IDENTIFIED BY 11}

PhysicalDeliveryOfficeNumber ::= PDSParameter

extension-OR-address-components EXTENSION-ATTRIBUTE ::=



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   {ExtensionORAddressComponents IDENTIFIED BY 12}

ExtensionORAddressComponents ::= PDSParameter

physical-delivery-personal-name EXTENSION-ATTRIBUTE ::=
   {PhysicalDeliveryPersonalName IDENTIFIED BY 13}

PhysicalDeliveryPersonalName ::= PDSParameter

physical-delivery-organization-name EXTENSION-ATTRIBUTE ::=
   {PhysicalDeliveryOrganizationName IDENTIFIED BY 14}

PhysicalDeliveryOrganizationName ::= PDSParameter

extension-physical-delivery-address-components EXTENSION-ATTRIBUTE ::=
   {ExtensionPhysicalDeliveryAddressComponents IDENTIFIED BY 15}

ExtensionPhysicalDeliveryAddressComponents ::= PDSParameter

unformatted-postal-address EXTENSION-ATTRIBUTE ::=
                        {UnformattedPostalAddress IDENTIFIED BY 16}

UnformattedPostalAddress ::= SET {
   printable-address SEQUENCE SIZE (1..ub-pds-physical-address-lines) OF
           PrintableString (SIZE (1..ub-pds-parameter-length)) OPTIONAL,
   teletex-string TeletexString (SIZE
                         (1..ub-unformatted-address-length)) OPTIONAL }

street-address EXTENSION-ATTRIBUTE ::=
                {StreetAddress IDENTIFIED BY 17}

StreetAddress ::= PDSParameter

post-office-box-address EXTENSION-ATTRIBUTE ::=
                {PostOfficeBoxAddress IDENTIFIED BY 18}

PostOfficeBoxAddress ::= PDSParameter

poste-restante-address EXTENSION-ATTRIBUTE ::=
                {PosteRestanteAddress IDENTIFIED BY 19}

PosteRestanteAddress ::= PDSParameter

unique-postal-name EXTENSION-ATTRIBUTE ::=
                {UniquePostalName IDENTIFIED BY 20}

UniquePostalName ::= PDSParameter




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local-postal-attributes EXTENSION-ATTRIBUTE ::=
                {LocalPostalAttributes IDENTIFIED BY 21}

LocalPostalAttributes ::= PDSParameter

PDSParameter ::= SET {
   printable-string PrintableString
                (SIZE(1..ub-pds-parameter-length)) OPTIONAL,
   teletex-string TeletexString
                (SIZE(1..ub-pds-parameter-length)) OPTIONAL }

extended-network-address EXTENSION-ATTRIBUTE ::=
                        {ExtendedNetworkAddress IDENTIFIED BY 22}

ExtendedNetworkAddress ::= CHOICE {

   e163-4-address SEQUENCE {
        number [0] NumericString (SIZE (1..ub-e163-4-number-length)),
        sub-address [1] NumericString
                (SIZE (1..ub-e163-4-sub-address-length)) OPTIONAL },
        psap-address [0] PresentationAddress }

terminal-type EXTENSION-ATTRIBUTE ::= {TerminalType IDENTIFIED BY 23}

TerminalType ::= INTEGER {
   telex (3),
   teletex (4),
   g3-facsimile (5),
   g4-facsimile (6),
   ia5-terminal (7),
   videotex (8) } (0..ub-integer-options)

--      Extension Domain-defined Attributes

teletex-domain-defined-attributes EXTENSION-ATTRIBUTE ::=
   {TeletexDomainDefinedAttributes IDENTIFIED BY 6}

TeletexDomainDefinedAttributes ::= SEQUENCE SIZE
   (1..ub-domain-defined-attributes) OF TeletexDomainDefinedAttribute

TeletexDomainDefinedAttribute ::= SEQUENCE {
        type TeletexString
               (SIZE (1..ub-domain-defined-attribute-type-length)),
        value TeletexString
               (SIZE (1..ub-domain-defined-attribute-value-length)) }

--  specifications of Upper Bounds
--  must be regarded as mandatory



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--  from Annex B of ITU-T X.411
--  Reference Definition of MTS Parameter Upper Bounds

--      Upper Bounds
ub-common-name-length INTEGER ::= 64
ub-country-name-alpha-length INTEGER ::= 2
ub-country-name-numeric-length INTEGER ::= 3
ub-domain-defined-attributes INTEGER ::= 4
ub-domain-defined-attribute-type-length INTEGER ::= 8
ub-domain-defined-attribute-value-length INTEGER ::= 128
ub-domain-name-length INTEGER ::= 16
ub-extension-attributes INTEGER ::= 256
ub-e163-4-number-length INTEGER ::= 15
ub-e163-4-sub-address-length INTEGER ::= 40
ub-generation-qualifier-length INTEGER ::= 3
ub-given-name-length INTEGER ::= 16
ub-initials-length INTEGER ::= 5
ub-integer-options INTEGER ::= 256
ub-numeric-user-id-length INTEGER ::= 32
ub-organization-name-length INTEGER ::= 64
ub-organizational-unit-name-length INTEGER ::= 32
ub-organizational-units INTEGER ::= 4
ub-pds-name-length INTEGER ::= 16
ub-pds-parameter-length INTEGER ::= 30
ub-pds-physical-address-lines INTEGER ::= 6
ub-postal-code-length INTEGER ::= 16
ub-surname-length INTEGER ::= 40
ub-terminal-id-length INTEGER ::= 24
ub-unformatted-address-length INTEGER ::= 180
ub-x121-address-length INTEGER ::= 16

-- Note - upper bounds on TeletexString are measured in characters.
-- A significantly greater number of octets will be required to hold
-- such a value.  As a minimum, 16 octets, or twice the specified upper
-- bound, whichever is the larger, should be allowed.

END

Appendix B. 1993 ASN.1 Structures and OIDs


PKIX1 DEFINITIONS IMPLICIT TAGS::=

BEGIN

--
-- Proposed PKIX OIDs
id-pkix  OBJECT IDENTIFIER  ::=



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         { iso(1) identified-organization(3) dod(6) internet(1)
                    security(5) mechanisms(5) pkix(7) }

-- PKIX arcs
-- arc for private certificate extensions
id-pe OBJECT IDENTIFIER  ::=  { id-pkix 1 }
 -- arc for policy qualifier types
id-qt OBJECT IDENTIFIER ::= { id-pkix 2 }
-- arc for extended key purpose OIDS
id-kp OBJECT IDENTIFIER ::= { id-pkix 3 }
-- arc for access descriptors
id-ad OBJECT IDENTIFIER ::= { id-pkix 48 }

-- pkix private extensions
id-pe-authorityInfoAccess OBJECT IDENTIFIER ::= { id-pe 1 }

-- policyQualifierIds for Internet policy qualifiers
id-qt-cps      OBJECT IDENTIFIER ::=  { id-qt 1 }
id-qt-unotice  OBJECT IDENTIFIER ::=  { id-qt 2 }

-- extended key purpose OIDs
id-kp-serverAuth      OBJECT IDENTIFIER ::= { id-kp 1 }
id-kp-clientAuth      OBJECT IDENTIFIER ::= { id-kp 2 }
id-kp-codeSigning     OBJECT IDENTIFIER ::= { id-kp 3 }
id-kp-emailProtection OBJECT IDENTIFIER ::= { id-kp 4 }
id-kp-ipsecEndSystem  OBJECT IDENTIFIER ::= { id-kp 5 }
id-kp-ipsecTunnel     OBJECT IDENTIFIER ::= { id-kp 6 }
id-kp-ipsecUser       OBJECT IDENTIFIER ::= { id-kp 7 }
id-kp-timeStamping    OBJECT IDENTIFIER ::= { id-kp 8 }

-- access descriptors for authority info access extension
id-ad-ocsp      OBJECT IDENTIFIER ::= { id-ad 1 }
id-ad-caIssuers OBJECT IDENTIFIER ::= { id-ad 2 }

-- attribute data types --

Attribute       ::=     SEQUENCE {
        type    AttributeValue,
        values  SET OF AttributeValue
                -- at least one value is required -- }

AttributeType           ::=     OBJECT IDENTIFIER

AttributeValue          ::=     ANY

AttributeTypeAndValue           ::=     SEQUENCE {
        type    AttributeType,
        value   AttributeValue }



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AttributeValueAssertion ::=     SEQUENCE {AttributeType, AttributeValue}

-- naming data types --

Name            ::=     CHOICE { -- only one possibility for now --
                                        rdnSequence  RDNSequence }

RDNSequence     ::=     SEQUENCE OF RelativeDistinguishedName

DistinguishedName       ::=     RDNSequence

RelativeDistinguishedName  ::=  SET SIZE (1 .. MAX) OF
                                               AttributeTypeAndValue

-- Directory string type --

DirectoryString ::= CHOICE {
        teletexString           TeletexString (SIZE (1..maxSize)),
        printableString         PrintableString (SIZE (1..maxSize)),
        universalString         UniversalString (SIZE (1..maxSize)),
      bmpString               BMPString (SIZE(1..maxSIZE))
                            }

-- from AuthenticationFramework
--    {joint-iso-ccitt ds(5) modules(1) authenticationFramework(7) 2}
-- note this module was defined with EXPLICIT TAGS

-- types --

Certificate            ::=    EXPLICIT SIGNED {SEQUENCE{
version                 [0]   Version DEFAULT v1,
serialNumber                  CertificateSerialNumber,
signature                     AlgorithmIdentifier,
issuer                        Name,
validity                      Validity,
subject                       Name,
subjectPublicKeyInfo          SubjectPublicKeyInfo}
issuerUniqueIdentifier  [1]   IMPLICIT UniqueIdentifier OPTIONAL,
                              ---if present, version must be  v1 or v2--
subjectUniqueIdentifier [2]   IMPLICIT UniqueIdentifier OPTIONAL,
                              ---if present, version must be v1 or v2--
extensions              [3]   Extensions Optional
                              --if present, version must be v3--}  }


Version                 ::=   INTEGER {v1(0), v2(1), v3(2) }

CertificateSerialNumber ::=     INTEGER



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Algorithmidentifier     ::=     SEQUENCE{
algorithm               ALGORITHM.&id({SupportedAlgorithms}),
parameters              ALGORITHM.&Type({SupportedAlgorithms}
                                           { @algorithm}) OPTIONAL }

--      Definition of the following information object is deferred.
--      SupportedAlgorithms     ALGORITHM  ::=  { ...|... }

Validity                        ::=     SEQUENCE{
notBefore       Time,
notAfter                Time }

Time ::= CHOICE {
        utcTime         UTCTime,
        generalTime             GeneralizedTime }

SubjectPublicKeyInfo    ::=     SEQUENCE{
algorithm                       AlgorithmIdentifier,
subjectPublicKey        BIT STRING}

Extensions        ::=   SEQUENCE SIZE (1..MAX) OF Extension

Extension         ::=   SEQUENCE {
extnId            EXTENSION.&id ({ExtensionSet}),
critical          BOOLEAN DEFAULT FALSE,
extnValue         OCTET STRING
                -- contains a DER encoding of a value of type
                -- &ExtnType for the
                -- extension object identified by extnId --

-- Definition of the following information object set is deferred,
-- The set is required to specify a table constraint on the critical
-- component of Extension.
--      ExtensionSet    EXTENSION       ::=     { ... | ... }

EXTENSION       ::=     CLASS
{
&id             OBJECT IDENTIFIER UNIQUE,
&ExtnType
}
WITH SYNTAX
{
SYNTAX          &ExtnType
IDENTIFIED BY   &id
}


CertificateList ::=    EXPLICIT SIGNED { SEQUENCE {



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version                Version  OPTIONAL, -- if present, must be v2
signature              AlgorithmIdentifier,
issuer                 Name,
thisUpdate             Time,
nextUpdate             Time OPTIONAL,
revokedCertificates    SEQUENCE OF SEQUENCE {
userCertificate        CertificateSerialNumber,
revocationDate         Time,
crlEntryExtensions     Extensions OPTIONAL } OPTIONAL,
crlExtensions          [0]      Extensions OPTIONAL }}


-- information object classes --

ALGORITHM       ::=     TYPE-IDENTIFIER

-- Parameterized Types --
HASHED {ToBeHashed}     ::=     OCTET STRING ( CONSTRAINED-BY {
    --must be the result of applying a hashing procedure to the --
    --DER-encoded octets of a value of -- ToBeHashed })

ENCRYPTED { ToBeEnciphered}     :=      BIT STRING ( CONSTRAINED BY {
    --must be the result of applying an encipherment procedure to the --
    --BER-encoded octets of a value of -- ToBeEnciphered })

SIGNED { ToBeSigned }   ::=     SEQUENCE{
        ToBeSigned,
        COMPONENTS OF SIGNATURE { ToBeSigned }),

SIGNATURE { OfSignature }       ::=     SEQUENCE {
        AlgorithmIdentifier,
        ENCRYPTED { HASHED { OfSignature }}}

-- Key and policy information extensions --

authorityKeyIdentifier EXTENSION ::= {
        SYNTAX          AuthorityKeyIdentifier
        IDENTIFIED BY   { id-ce 35 } }

AuthorityKeyIdentifier ::= SEQUENCE {
    keyIdentifier               [0] KeyIdentifier            OPTIONAL,
    authorityCertIssuer         [1] GeneralNames             OPTIONAL,
    authorityCertSerialNumber   [2] CertificateSerialNumber  OPTIONAL }
        ( WITH COMPONENTS       {..., authorityCertIssuer PRESENT,
                                authorityCertSerialNumber PRESENT} |
         WITH COMPONENTS        {..., authorityCertIssuer ABSENT,
                                authorityCertSerialNumber ABSENT} )




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KeyIdentifier ::= OCTET STRING

subjectKeyIdentifier EXTENSION ::= {
        SYNTAX          SubjectKeyIdentifier
        IDENTIFIED BY   { id-ce 14 } }

SubjectKeyIdentifier ::= KeyIdentifier

keyUsage EXTENSION ::= {
        SYNTAX  KeyUsage
        IDENTIFIED BY { id-ce 15 } }

KeyUsage ::= BIT STRING {
        digitalSignature     (0),
        nonRepudiation       (1),
        keyEncipherment      (2),
        dataEncipherment     (3),
        keyAgreement         (4),
        keyCertSign          (5),
        cRLSign              (6) }

privateKeyUsagePeriod EXTENSION ::= {
        SYNTAX  PrivateKeyUsagePeriod
        IDENTIFIED BY { id-ce 16 } }

PrivateKeyUsagePeriod ::= SEQUENCE {
        notBefore       [0]     GeneralizedTime OPTIONAL,
        notAfter        [1]     GeneralizedTime OPTIONAL }
        ( WITH COMPONENTS       {..., notBefore PRESENT} |
        WITH COMPONENTS         {..., notAfter PRESENT} )

certificatePolicies EXTENSION ::= {
        SYNTAX  CertificatePoliciesSyntax
        IDENTIFIED BY { id-ce 32 } }

CertificatePoliciesSyntax ::=
                SEQUENCE SIZE (1..MAX) OF PolicyInformation

PolicyInformation ::= SEQUENCE {
        policyIdentifier   CertPolicyId,
        policyQualifiers   SEQUENCE SIZE (1..MAX) OF
                PolicyQualifierInfo OPTIONAL }

CertPolicyId ::= OBJECT IDENTIFIER

PolicyQualifierInfo ::= SEQUENCE {
        policyQualifierId       CERT-POLICY-QUALIFIER.&id
                                    ({SupportedPolicyQualifiers}),



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        qualifier               CERT-POLICY-QUALIFIER.&Qualifier
                                    ({SupportedPolicyQualifiers}
                                    {@policyQualifierId})OPTIONAL }

SupportedPolicyQualifiers CERT-POLICY-QUALIFIER ::= { ... }

CERT-POLICY-QUALIFIER ::= CLASS {
        &id             OBJECT IDENTIFIER UNIQUE,
        &Qualifier      OPTIONAL }
WITH SYNTAX {
        POLICY-QUALIFIER-ID     &id
        [QUALIFIER-TYPE &Qualifier] }

policyMappings EXTENSION ::= {
        SYNTAX  PolicyMappingsSyntax
        IDENTIFIED BY { id-ce 33 } }

PolicyMappingsSyntax ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE {
        issuerDomainPolicy           CertPolicyId,
        subjectDomainPolicy          CertPolicyId }

supportedAlgorithms ATTRIBUTE ::= {
        WITH SYNTAX SupportedAlgorithm
        EQUALITY MATCHING RULE algorithmIdentifierMatch
        ID { id-at 52 } }

SupportedAlgorithm ::= SEQUENCE {
   algorithmIdentifier         AlgorithmIdentifier,
   intendedUsage               [0]  KeyUsage OPTIONAL,
   intendedCertificatePolicies [1]  CertificatePoliciesSyntax OPTIONAL }

-- Certificate subject and certificate issuer attributes extensions --

subjectAltName EXTENSION ::= {
        SYNTAX  GeneralNames
        IDENTIFIED BY { id-ce 17 } }

GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName

GeneralName ::= CHOICE {
        otherName                   [0] INSTANCE OF OTHER-NAME,
        rfc822Name                  [1] IA5String,
        dNSName                     [2] IA5String,
        x400Address                 [3] ORAddress,
        directoryName               [4] Name,
        ediPartyName                [5] EDIPartyName,
        uniformResourceIdentifier   [6] IA5String,
        iPAddress                   [7] OCTET STRING,



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        registeredID                [8] OBJECT IDENTIFIER }

OTHER-NAME ::= TYPE-IDENTIFIER

EDIPartyName ::= SEQUENCE {
        nameAssigner        [0] DirectoryString {ub-name} OPTIONAL,
        partyName           [1] DirectoryString {ub-name} }

issuerAltName EXTENSION ::= {
        SYNTAX  GeneralNames
        IDENTIFIED BY { id-ce 18 } }

subjectDirectoryAttributes EXTENSION ::= {
        SYNTAX  AttributesSyntax
        IDENTIFIED BY { id-ce 9 } }

AttributesSyntax ::= SEQUENCE SIZE (1..MAX) OF Attribute


-- Certification path constraints extensions --

basicConstraints EXTENSION ::= {
        SYNTAX  BasicConstraintsSyntax
        IDENTIFIED BY { id-ce 19 } }

BasicConstraintsSyntax ::= SEQUENCE {
        cA                      BOOLEAN DEFAULT FALSE,
        pathLenConstraint       INTEGER (0..MAX) OPTIONAL }

nameConstraints EXTENSION ::= {
        SYNTAX  NameConstraintsSyntax
        IDENTIFIED BY { id-ce 30 } }

NameConstraintsSyntax ::= SEQUENCE {
        permittedSubtrees       [0]     GeneralSubtrees OPTIONAL,
        excludedSubtrees        [1]     GeneralSubtrees OPTIONAL }

GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree

GeneralSubtree ::= SEQUENCE {
        base                    GeneralName,
        minimum         [0]     BaseDistance DEFAULT 0,
        maximum         [1]     BaseDistance OPTIONAL }

BaseDistance ::= INTEGER (0..MAX)

policyConstraints EXTENSION ::= {
        SYNTAX  PolicyConstraintsSyntax



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        IDENTIFIED BY { id-ce 36 } }

PolicyConstraints Syntax ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE {
        requireExplicitPolicy   [0] SkipCerts OPTIONAL,
        inhibitPolicyMapping    [1] SkipCerts OPTIONAL }

SkipCerts ::= INTEGER (0..MAX)

-- Basic CRL extensions --

cRLNumber EXTENSION ::= {
        SYNTAX  CRLNumber
        IDENTIFIED BY { id-ce 20 } }

CRLNumber ::= INTEGER (0..MAX)

reasonCode EXTENSION ::= {
        SYNTAX  CRLReason
        IDENTIFIED BY { id-ce 21 } }

CRLReason ::= ENUMERATED {
        unspecified                     (0),
        keyCompromise           (1),
        cACompromise            (2),
        affiliationChanged              (3),
        superseded                      (4),
        cessationOfOperation            (5),
        certificateHold                 (6),
        removeFromCRL           (8) }

instructionCode EXTENSION ::= {
        SYNTAX  HoldInstruction
        IDENTIFIED BY { id-ce 23 } }

HoldInstruction ::= OBJECT IDENTIFIER

invalidityDate EXTENSION ::= {
        SYNTAX  GeneralizedTime
        IDENTIFIED BY { id-ce 24 } }


-- CRL distribution points and delta-CRL extensions --

cRLDistributionPoints EXTENSION ::= {
        SYNTAX  CRLDistPointsSyntax
        IDENTIFIED BY   { id-ce 31 } }

CRLDistPointsSyntax ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint



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DistributionPoint ::= SEQUENCE {
        distributionPoint       [0]     DistributionPointName OPTIONAL,
        reasons         [1]     ReasonFlags OPTIONAL,
        cRLIssuer               [2]     GeneralNames OPTIONAL }

DistributionPointName ::= CHOICE {
        fullName                [0]     GeneralNames,
        nameRelativeToCRLIssuer [1]     RelativeDistinguishedName }

ReasonFlags ::= BIT STRING {
        unused                  (0),
        keyCompromise           (1),
        caCompromise            (2),
        affiliationChanged      (3),
        superseded              (4),
        cessationOfOperation    (5),
        certificateHold         (6) }

issuingDistributionPoint EXTENSION ::= {
        SYNTAX  IssuingDistPointSyntax
        IDENTIFIED BY   { id-ce 28 } }

IssuingDistPointSyntax ::= SEQUENCE {
        distributionPoint       [0] DistributionPointName OPTIONAL,
        onlyContainsUserCerts   [1] BOOLEAN DEFAULT FALSE,
        onlyContainsCACerts     [2] BOOLEAN DEFAULT FALSE,
        onlySomeReasons         [3] ReasonFlags OPTIONAL,
        indirectCRL             [4] BOOLEAN DEFAULT FALSE }

certificateIssuer EXTENSION ::= {
        SYNTAX          GeneralNames
        IDENTIFIED BY           { id-ce 29 } }

deltaCRLIndicator EXTENSION ::= {
        SYNTAX          BaseCRLNumber
        IDENTIFIED BY   { id-ce 27 } }

BaseCRLNumber ::= CRLNumber

deltaRevocationList ATTRIBUTE ::= {
        WITH SYNTAX     CertificateList
        EQUALITY MATCHING RULE certificateListExactMatch
        ID      {id-at 53 } }


-- Object identifier assignments --

id-ce-subjectDirectoryAttributes OBJECT IDENTIFIER  ::= {id-ce 9}



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id-ce-subjectKeyIdentifier       OBJECT IDENTIFIER  ::= {id-ce 14}
id-ce-keyUsage          OBJECT IDENTIFIER       ::=     {id-ce 15}
id-ce-privateKeyUsagePeriod     OBJECT IDENTIFIER  ::=  {id-ce 16}
id-ce-subjectAltName    OBJECT IDENTIFIER       ::=     {id-ce 17}
id-ce-issuerAltName     OBJECT IDENTIFIER       ::=     {id-ce 18}
id-ce-basicConstraints  OBJECT IDENTIFIER       ::=     {id-ce 19}
id-ce-cRLNumber         OBJECT IDENTIFIER       ::=     {id-ce 20}
id-ce-reasonCode        OBJECT IDENTIFIER       ::=     {id-ce 21}
id-ce-instructionCode   OBJECT IDENTIFIER       ::=     {id-ce 23}
id-ce-invalidityDate    OBJECT IDENTIFIER       ::=     {id-ce 24}
id-ce-deltaCRLIndicator OBJECT IDENTIFIER       ::=     {id-ce 27}
id-ce-issuingDistributionPoint  OBJECT IDENTIFIER  ::=  {id-ce 28}
id-ce-certificateIssuer OBJECT IDENTIFIER       ::=     {id-ce 29}
id-ce-nameConstraints   OBJECT IDENTIFIER       ::=     {id-ce 30}
id-ce-cRLDistributionPoints     OBJECT IDENTIFIER  ::=  {id-ce 31}
id-ce-certificatePolicies       OBJECT IDENTIFIER  ::=  {id-ce 32}
id-ce-policyMappings    OBJECT IDENTIFIER       ::=     {id-ce 33}
id-ce-policyConstraints OBJECT IDENTIFIER       ::=     {id-ce 36}
id-ce-authorityKeyIdentifier    OBJECT IDENTIFIER  ::=  {id-ce 35}

-- PKIX 1 extensions

id-pe-authorityInfoAccess OBJECT IDENTIFIER ::= { id-pe 1 }

AuthorityInfoAccessSyntax  ::=
        SEQUENCE SIZE (1..MAX) OF AccessDescription

AccessDescription  ::=  SEQUENCE {
        accessMethod          OBJECT IDENTIFIER,
        accessLocation        GeneralName  }

CPSuri ::= IA5String

UserNotice ::= CHOICE {
  visibleString     VisibleString,
  bmpString         BMPString
                      }

-- misc missing ASN.1

PresentationAddress ::= SEQUENCE {
        pSelector       [0] EXPLICIT OCTET STRING OPTIONAL,
        sSelector       [1] EXPLICIT OCTET STRING OPTIONAL,
        tSelector       [2] EXPLICIT OCTET STRING OPTIONAL,
        nAddresses      [3] EXPLICIT SET SIZE (1..MAX) OF OCTET STRING}


-- The following OBJECT IDENTIFIERS are not used by this specification:



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-- {id-ce 2}, {id-ce 3}, {id-ce 4}, {id-ce 5}, {id-ce 6}, {id-ce 7},
-- {id-ce 8}, {id-ce 10}, {id-ce 11}, {id-ce 12}, {id-ce 13},
-- {id-ce 22}, {id-ce 25}, {id-ce 26}

-- X.400, Algorithm Identifier, and maximum values Module

ORAddressAndOrDirectoryName ::= ORName

ORAddressAndOptionalDirectoryName ::= ORName

ORName ::= [APPLICATION 0] SEQUENCE {
   -- address -- COMPONENTS OF ORAddress,
   directory-name [0] Name OPTIONAL }

ORAddress ::= SEQUENCE {
   built-in-standard-attributes BuiltInStandardAttributes,
   built-in-domain-defined-attributes
                        BuiltInDomainDefinedAttributes OPTIONAL,
   -- see also teletex-domain-defined-attributes
   extension-attributes ExtensionAttributes OPTIONAL }

--  The OR-address is semantically absent from the OR-name if the
--  built-in-standard-attribute sequence is empty and the
--  built-in-domain-defined-attributes and extension-attributes are
--  both omitted.

--      Built-in Standard Attributes

BuiltInStandardAttributes ::= SEQUENCE {
   country-name CountryName OPTIONAL,
   administration-domain-name AdministrationDomainName OPTIONAL,
   network-address      [0] NetworkAddress OPTIONAL,
   -- see also extended-network-address
   terminal-identifier  [1] TerminalIdentifier OPTIONAL,
   private-domain-name  [2] PrivateDomainName OPTIONAL,
   organization-name    [3] OrganizationName OPTIONAL,
   -- see also teletex-organization-name
   numeric-user-identifier      [4] NumericUserIdentifier OPTIONAL,
   personal-name        [5] PersonalName OPTIONAL,
   -- see also teletex-personal-name
   organizational-unit-names    [6] OrganizationalUnitNames OPTIONAL
   -- see also teletex-organizational-unit-names -- }

CountryName ::= [APPLICATION 1] CHOICE {
   x121-dcc-code NumericString
                (SIZE (ub-country-name-numeric-length)),
   iso-3166-alpha2-code PrintableString
                (SIZE (ub-country-name-alpha-length)) }



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AdministrationDomainName ::= [APPLICATION 2] CHOICE {
   numeric NumericString (SIZE (0..ub-domain-name-length)),
   printable PrintableString (SIZE (0..ub-domain-name-length)) }

NetworkAddress ::= X121Address
-- see also extended-network-address

X121Address ::= NumericString (SIZE (1..ub-x121-address-length))

TerminalIdentifier ::= PrintableString (SIZE (1..ub-terminal-id-length))

PrivateDomainName ::= CHOICE {
   numeric NumericString (SIZE (1..ub-domain-name-length)),
   printable PrintableString (SIZE (1..ub-domain-name-length)) }

OrganizationName ::= PrintableString
                           (SIZE (1..ub-organization-name-length))
-- see also teletex-organization-name

NumericUserIdentifier ::= NumericString
                             (SIZE (1..ub-numeric-user-id-length))

PersonalName ::= SET {
   surname    [0] PrintableString (SIZE (1..ub-surname-length)),
   given-name [1] PrintableString
                        (SIZE (1..ub-given-name-length)) OPTIONAL,
   initials   [2] PrintableString
                        (SIZE (1..ub-initials-length)) OPTIONAL,
   generation-qualifier [3] PrintableString
                (SIZE (1..ub-generation-qualifier-length)) OPTIONAL}
-- see also teletex-personal-name

OrganizationalUnitNames ::= SEQUENCE SIZE (1..ub-organizational-units)
                                        OF OrganizationalUnitName
-- see also teletex-organizational-unit-names

OrganizationalUnitName ::= PrintableString (SIZE
                        (1..ub-organizational-unit-name-length))

--      Built-in Domain-defined Attributes
BuiltInDomainDefinedAttributes ::= SEQUENCE SIZE
                                (1..ub-domain-defined-attributes) OF
                                BuiltInDomainDefinedAttribute

BuiltInDomainDefinedAttribute ::= SEQUENCE {
   type PrintableString (SIZE
                (1..ub-domain-defined-attribute-type-length)),
   value PrintableString (SIZE



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                (1..ub-domain-defined-attribute-value-length)) }

--      Extension Attributes

ExtensionAttributes ::= SET SIZE (1..ub-extension-attributes)
                                        OF ExtensionAttribute
ExtensionAttribute ::= SEQUENCE {
        extension-attribute-type [0] EXTENSION-ATTRIBUTE.&id
                                        ({ExtensionAttributeTable}),
        extension-attribute-value [1] EXTENSION-ATTRIBUTE.&Type
             ({ExtensionAttributeTable} {@extension-attribute-type}) }

EXTENSION-ATTRIBUTE ::= CLASS {
        &id     INTEGER (0..ub-extension-attributes) UNIQUE,
        &Type }
WITH SYNTAX {&Type IDENTIFIED BY &id}

ExtensionAttributeTable EXTENSION-ATTRIBUTE ::= {
        common-name |
        teletex-common-name |
        teletex-organization-name |
        teletex-personal-name |
        teletex-organizational-unit-names |
        teletex-domain-defined-attributes |
        pds-name |
        physical-delivery-country-name |
        postal-code |
        physical-delivery-office-name |
        physical-delivery-office-number |
        extension-OR-address-components |
        physical-delivery-personal-name |
        physical-delivery-organization-name |
        extension-physical-delivery-address-components |
        unformatted-postal-address |
        street-address |
        post-office-box-address |
        poste-restante-address |
        unique-postal-name |
        local-postal-attributes |
        extended-network-address |
        terminal-type }

--      Extension Standard Attributes

common-name EXTENSION-ATTRIBUTE ::= {CommonName IDENTIFIED BY 1}

CommonName ::= PrintableString (SIZE (1..ub-common-name-length))




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teletex-common-name EXTENSION-ATTRIBUTE ::=
                {TeletexCommonName IDENTIFIED BY 2}

TeletexCommonName ::= TeletexString (SIZE (1..ub-common-name-length))

teletex-organization-name EXTENSION-ATTRIBUTE ::=
                {TeletexOrganizationName IDENTIFIED BY 3}

TeletexOrganizationName ::=
                TeletexString (SIZE (1..ub-organization-name-length))

teletex-personal-name EXTENSION-ATTRIBUTE ::=
                {TeletexPersonalName IDENTIFIED BY 4}

TeletexPersonalName ::= SET {
   surname [0] TeletexString (SIZE (1..ub-surname-length)),
   given-name [1] TeletexString
                (SIZE (1..ub-given-name-length)) OPTIONAL,
   initials [2] TeletexString (SIZE (1..ub-initials-length)) OPTIONAL,
   generation-qualifier [3] TeletexString (SIZE
                (1..ub-generation-qualifier-length)) OPTIONAL }

teletex-organizational-unit-names EXTENSION-ATTRIBUTE ::=
   {TeletexOrganizationalUnitNames IDENTIFIED BY 5}

TeletexOrganizationalUnitNames ::= SEQUENCE SIZE
        (1..ub-organizational-units) OF TeletexOrganizationalUnitName

TeletexOrganizationalUnitName ::= TeletexString
                        (SIZE (1..ub-organizational-unit-name-length))

pds-name EXTENSION-ATTRIBUTE ::= {PDSName IDENTIFIED BY 7}

PDSName ::= PrintableString (SIZE (1..ub-pds-name-length))

physical-delivery-country-name EXTENSION-ATTRIBUTE ::=
   {PhysicalDeliveryCountryName IDENTIFIED BY 8}

PhysicalDeliveryCountryName ::= CHOICE {
   x121-dcc-code NumericString (SIZE (ub-country-name-numeric-length)),
   iso-3166-alpha2-code PrintableString
                        (SIZE (ub-country-name-alpha-length)) }

postal-code EXTENSION-ATTRIBUTE ::= {PostalCode IDENTIFIED BY 9}

PostalCode ::= CHOICE {
   numeric-code NumericString (SIZE (1..ub-postal-code-length)),
   printable-code PrintableString (SIZE (1..ub-postal-code-length)) }



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physical-delivery-office-name EXTENSION-ATTRIBUTE ::=
                        {PhysicalDeliveryOfficeName IDENTIFIED BY 10}

PhysicalDeliveryOfficeName ::= PDSParameter

physical-delivery-office-number EXTENSION-ATTRIBUTE ::=
   {PhysicalDeliveryOfficeNumber IDENTIFIED BY 11}

PhysicalDeliveryOfficeNumber ::= PDSParameter

extension-OR-address-components EXTENSION-ATTRIBUTE ::=
   {ExtensionORAddressComponents IDENTIFIED BY 12}

ExtensionORAddressComponents ::= PDSParameter

physical-delivery-personal-name EXTENSION-ATTRIBUTE ::=
   {PhysicalDeliveryPersonalName IDENTIFIED BY 13}

PhysicalDeliveryPersonalName ::= PDSParameter

physical-delivery-organization-name EXTENSION-ATTRIBUTE ::=
   {PhysicalDeliveryOrganizationName IDENTIFIED BY 14}

PhysicalDeliveryOrganizationName ::= PDSParameter

extension-physical-delivery-address-components EXTENSION-ATTRIBUTE ::=
   {ExtensionPhysicalDeliveryAddressComponents IDENTIFIED BY 15}

ExtensionPhysicalDeliveryAddressComponents ::= PDSParameter

unformatted-postal-address EXTENSION-ATTRIBUTE ::=
                        {UnformattedPostalAddress IDENTIFIED BY 16}

UnformattedPostalAddress ::= SET {
   printable-address SEQUENCE SIZE (1..ub-pds-physical-address-lines) OF
           PrintableString (SIZE (1..ub-pds-parameter-length)) OPTIONAL,
   teletex-string TeletexString (SIZE
                         (1..ub-unformatted-address-length)) OPTIONAL }

street-address EXTENSION-ATTRIBUTE ::=
                {StreetAddress IDENTIFIED BY 17}

StreetAddress ::= PDSParameter

post-office-box-address EXTENSION-ATTRIBUTE ::=
                {PostOfficeBoxAddress IDENTIFIED BY 18}

PostOfficeBoxAddress ::= PDSParameter



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poste-restante-address EXTENSION-ATTRIBUTE ::=
                {PosteRestanteAddress IDENTIFIED BY 19}

PosteRestanteAddress ::= PDSParameter

unique-postal-name EXTENSION-ATTRIBUTE ::=
                {UniquePostalName IDENTIFIED BY 20}

UniquePostalName ::= PDSParameter

local-postal-attributes EXTENSION-ATTRIBUTE ::=
                {LocalPostalAttributes IDENTIFIED BY 21}

LocalPostalAttributes ::= PDSParameter

PDSParameter ::= SET {
   printable-string PrintableString
            (SIZE(1..ub-pds-parameter-length)) OPTIONAL,
   teletex-string TeletexString
            (SIZE(1..ub-pds-parameter-length)) OPTIONAL }

extended-network-address EXTENSION-ATTRIBUTE ::=
                {ExtendedNetworkAddress IDENTIFIED BY 22}

ExtendedNetworkAddress ::= CHOICE {
        e163-4-address SEQUENCE {
                number [0] NumericString
                   (SIZE (1..ub-e163-4-number-length)),
                sub-address [1] NumericString
                   (SIZE (1..ub-e163-4-sub-address-length)) OPTIONAL},
        psap-address [0] PresentationAddress }

terminal-type EXTENSION-ATTRIBUTE ::= {TerminalType IDENTIFIED BY 23}

TerminalType ::= INTEGER {
   telex (3),
   teletex (4),
   g3-facsimile (5),
   g4-facsimile (6),
   ia5-terminal (7),
   videotex (8) } (0..ub-integer-options)

--      Extension Domain-defined Attributes

teletex-domain-defined-attributes EXTENSION-ATTRIBUTE ::=
   {TeletexDomainDefinedAttributes IDENTIFIED BY 6}

TeletexDomainDefinedAttributes ::= SEQUENCE SIZE



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   (1..ub-domain-defined-attributes) OF TeletexDomainDefinedAttribute

TeletexDomainDefinedAttribute ::= SEQUENCE {
    type TeletexString
         (SIZE (1..ub-domain-defined-attribute-type-length)),
    value TeletexString
         (SIZE (1..ub-domain-defined-attribute-value-length)) }

--  specifications of Upper Bounds
--  must be regarded as mandatory
--  from Annex B of ITU-T X.411
--  Reference Definition of MTS Parameter Upper Bounds

--      Upper Bounds
ub-common-name-length INTEGER ::= 64
ub-country-name-alpha-length INTEGER ::= 2
ub-country-name-numeric-length INTEGER ::= 3
ub-domain-defined-attributes INTEGER ::= 4
ub-domain-defined-attribute-type-length INTEGER ::= 8
ub-domain-defined-attribute-value-length INTEGER ::= 128
ub-domain-name-length INTEGER ::= 16
ub-extension-attributes INTEGER ::= 256
ub-e163-4-number-length INTEGER ::= 15
ub-e163-4-sub-address-length INTEGER ::= 40
ub-generation-qualifier-length INTEGER ::= 3
ub-given-name-length INTEGER ::= 16
ub-initials-length INTEGER ::= 5
ub-integer-options INTEGER ::= 256
ub-numeric-user-id-length INTEGER ::= 32
ub-organization-name-length INTEGER ::= 64
ub-organizational-unit-name-length INTEGER ::= 32
ub-organizational-units INTEGER ::= 4
ub-pds-name-length INTEGER ::= 16
ub-pds-parameter-length INTEGER ::= 30
ub-pds-physical-address-lines INTEGER ::= 6
ub-postal-code-length INTEGER ::= 16
ub-surname-length INTEGER ::= 40
ub-terminal-id-length INTEGER ::= 24
ub-unformatted-address-length INTEGER ::= 180
ub-x121-address-length INTEGER ::= 16

-- Note - upper bounds on TeletexString are measured in characters.
-- A significantly greater number of octets will be required to hold
-- such a value.  As a minimum, 16 octets, or twice the specified upper
-- bound, whichever is the larger, should be allowed.

END




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Appendix C. ASN.1 Notes

The construct

       SEQUENCE SIZE (1..MAX) OF

appears in several ASN.1 constructs. A valid ASN.1 sequence will have
zero or more entries. The SIZE (1..MAX) construct constrains the
sequence to have at least one entry. MAX indicates the upper bound is
unspecified. Implementations are free to choose an upper bound that
suits their environment.

The construct

      positiveInt ::= INTEGER (0..MAX)

defines positiveInt as a subtype of INTEGER containing integers greater
than or equal to zero.  The upper bound is unspecified. Implementations
are free to select an upper bound that suits their environment.

   The character string type PrintableString supports a very basic Latin
   character set:  the lower case letters 'a' through 'z', upper case
   letters 'A' through 'Z', the digits '0' through '9', eleven special
   characters ' " ( ) + , - . / : ? and space.

   The character string type TeletexString is a superset of
   PrintableString.  TeletexString supports a fairly standard (ascii-
   like) Latin character set, Latin characters with non-spacing accents
   and Japanese characters.

   The character string type UniversalString supports any of the
   characters allowed by ISO 10646-1. ISO 10646 is the Universal
   multiple-octet coded Character Set (UCS).  ISO 10646-1 specifes the
   architecture and the "basic multilingual plane" - a large standard
   character set which includes all major world character standards.

Appendix D. Examples

   This section contains four examples; three certificates and a CRL.
   The first two certificates and the CRL comprise a minimal
   certification path.

   Section D.1 contains two annotated hex dumps of a "self-signed"
   certificate issued by a CA whose distinguished name is
   cn=us,o=gov,ou=nist.  The certificate contains a DSA public key with
   parameters, and is signed by the corresponding DSA private key. The
   first hex dump is a basic dump of the ASN.1 encoding and does not not
   reflect the fact that the object is a certificate. The second dump



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   identfies the values of the various certificate fields.

   Section D.2 contains  an annotated hex dump of an end-entity
   certificate.  The end entity certificate contains a DSA public key,
   and is signed by the private key corresponding to the "self-signed"
   certificate in section D.1.   The first hex dump is a basic dump of
   the ASN.1 encoding and does not not reflect the fact that the object
   is a certificate. The second dump identfies the values of the various
   certificate fields.

   Section D.3 contains a dump of an end entity certificate which
   contains an RSA public key and is signed with RSA and MD5.  (This
   certificate is not part of the minimal certification path.)

   Section D.4 contains an annotated hex dump of a CRL.  The CRL is
   issued by the CA whose distinguished name is cn=us,o=gov,ou=nist and
   the list of revoked certifcates includes the end entity certificate
   presented in D.2.  The hex dump is a basic dump of the ASN.1
   encoding.

D.1 Certificate

   This section contains an annotated hex dump of a 662 byte version 3
   certificate.  The certificate contains the following information:
   (a) the serial number is 17 (11 hex);
   (b) the certificate is signed with DSA and the SHA-1 hash algorithm;
   (c) the issuer's distinguished name is OU=nist;O=gov;C=US
   (d) and the subject's distinguished name is OU=nist;O=gov;C=US
   (e) the certificate was issued on June 30, 1997 and will expire on
   December 31, 1997;
   (f) the certificate contains a 1024 bit DSA public key; and
   (g) the certificate is a CA certificate (as indicated through the
   basic constraints extension.)

D.1.1 ASN.1 Dump of "Self-Signed" Certificate

get 0, len=662 (662 bytes in file)
0000 30 82 02 92  658: SEQUENCE
0004 30 82 02 52  594: . SEQUENCE
0008 a0 03          3: . . [0]
0010 02 01          1: . . . INTEGER 2
0013 02 01          1: . . INTEGER 17
0016 30 09          9: . . SEQUENCE
0018 06 07          7: . . . OID 1.2.840.10040.4.3: dsa-with-sha
0027 30 2a         42: . . SEQUENCE
0029 31 0b         11: . . . SET
0031 30 09          9: . . . . SEQUENCE
0033 06 03          3: . . . . . OID 2.5.4.6: C



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0038 13 02          2: . . . . . PrintableString  'US'
0042 31 0c         12: . . . SET
0044 30 0a         10: . . . . SEQUENCE
0046 06 03          3: . . . . . OID 2.5.4.10: O
0051 13 03          3: . . . . . PrintableString  'gov'
0056 31 0d         13: . . . SET
0058 30 0b         11: . . . . SEQUENCE
0060 06 03          3: . . . . . OID 2.5.4.11: OU
0065 13 04          4: . . . . . PrintableString  'nist'
0071 30 1e         30: . . SEQUENCE
0073 17 0d         13: . . . UTCTime  '970630000000Z'
0088 17 0d         13: . . . UTCTime  '971231000000Z'
0103 30 2a         42: . . SEQUENCE
0105 31 0b         11: . . . SET
0107 30 09          9: . . . . SEQUENCE
0109 06 03          3: . . . . . OID 2.5.4.6: C
0114 13 02          2: . . . . . PrintableString  'US'
0118 31 0c         12: . . . SET
0120 30 0a         10: . . . . SEQUENCE
0122 06 03          3: . . . . . OID 2.5.4.10: O
0127 13 03          3: . . . . . PrintableString  'gov'
0132 31 0d         13: . . . SET
0134 30 0b         11: . . . . SEQUENCE
0136 06 03          3: . . . . . OID 2.5.4.11: OU
0141 13 04          4: . . . . . PrintableString  'nist'
0147 30 82 01 b4  436: . . SEQUENCE
0151 30 82 01 29  297: . . . SEQUENCE
0155 06 07          7: . . . . OID 1.2.840.10040.4.1: dsa
0164 30 82 01 1c  284: . . . . SEQUENCE
0168 02 81 80     128: . . . . . INTEGER
                     : d4 38 02 c5 35 7b d5 0b a1 7e 5d 72 59 63 55 d3
                     : 45 56 ea e2 25 1a 6b c5 a4 ab aa 0b d4 62 b4 d2
                     : 21 b1 95 a2 c6 01 c9 c3 fa 01 6f 79 86 83 3d 03
                     : 61 e1 f1 92 ac bc 03 4e 89 a3 c9 53 4a f7 e2 a6
                     : 48 cf 42 1e 21 b1 5c 2b 3a 7f ba be 6b 5a f7 0a
                     : 26 d8 8e 1b eb ec bf 1e 5a 3f 45 c0 bd 31 23 be
                     : 69 71 a7 c2 90 fe a5 d6 80 b5 24 dc 44 9c eb 4d
                     : f9 da f0 c8 e8 a2 4c 99 07 5c 8e 35 2b 7d 57 8d
0299 02 14         20: . . . . . INTEGER
                     : a7 83 9b f3 bd 2c 20 07 fc 4c e7 e8 9f f3 39 83
                     : 51 0d dc dd
0321 02 81 80     128: . . . . . INTEGER
                     : 0e 3b 46 31 8a 0a 58 86 40 84 e3 a1 22 0d 88 ca
                     : 90 88 57 64 9f 01 21 e0 15 05 94 24 82 e2 10 90
                     : d9 e1 4e 10 5c e7 54 6b d4 0c 2b 1b 59 0a a0 b5
                     : a1 7d b5 07 e3 65 7c ea 90 d8 8e 30 42 e4 85 bb
                     : ac fa 4e 76 4b 78 0e df 6c e5 a6 e1 bd 59 77 7d
                     : a6 97 59 c5 29 a7 b3 3f 95 3e 9d f1 59 2d f7 42



Housley, Ford, Polk, & Solo                                    [Page 97]


INTERNET DRAFT                                          October 14, 1997


                     : 87 62 3f f1 b8 6f c7 3d 4b b8 8d 74 c4 ca 44 90
                     : cf 67 db de 14 60 97 4a d1 f7 6d 9e 09 94 c4 0d
0452 03 81 84     132: . . . BIT STRING  (0 unused bits)
                     : 02 81 80 aa 98 ea 13 94 a2 db f1 5b 7f 98 2f 78
                     : e7 d8 e3 b9 71 86 f6 80 2f 40 39 c3 da 3b 4b 13
                     : 46 26 ee 0d 56 c5 a3 3a 39 b7 7d 33 c2 6b 5c 77
                     : 92 f2 55 65 90 39 cd 1a 3c 86 e1 32 eb 25 bc 91
                     : c4 ff 80 4f 36 61 bd cc e2 61 04 e0 7e 60 13 ca
                     : c0 9c dd e0 ea 41 de 33 c1 f1 44 a9 bc 71 de cf
                     : 59 d4 6e da 44 99 3c 21 64 e4 78 54 9d d0 7b ba
                     : 4e f5 18 4d 5e 39 30 bf e0 d1 f6 f4 83 25 4f 14
                     : aa 71 e1
0587 a3 0d         13: . . [3]
0589 30 0b         11: . . . SEQUENCE
0591 30 09          9: . . . . SEQUENCE
0593 06 03          3: . . . . . OID 2.5.29.19: basicConstraints
0598 04 02          2: . . . . . OCTET STRING
                     : 30 00
0602 30 09          9: . SEQUENCE
0604 06 07          7: . . OID 1.2.840.10040.4.3: dsa-with-sha
0613 03 2f         47: . BIT STRING  (0 unused bits)
                     : 30 2c 02 14 a0 66 c1 76 33 99 13 51 8d 93 64 2f
                     : ca 13 73 de 79 1a 7d 33 02 14 5d 90 f6 ce 92 4a
                     : bf 29 11 24 80 28 a6 5a 8e 73 b6 76 02 68

------- extensions ----------

printber -s 456 pkix-ex1.ber
get 0, len=131 (662 bytes in file)
0000 02 81 80     128: INTEGER
                     : aa 98 ea 13 94 a2 db f1 5b 7f 98 2f 78 e7 d8 e3
                     : b9 71 86 f6 80 2f 40 39 c3 da 3b 4b 13 46 26 ee
                     : 0d 56 c5 a3 3a 39 b7 7d 33 c2 6b 5c 77 92 f2 55
                     : 65 90 39 cd 1a 3c 86 e1 32 eb 25 bc 91 c4 ff 80
                     : 4f 36 61 bd cc e2 61 04 e0 7e 60 13 ca c0 9c dd
                     : e0 ea 41 de 33 c1 f1 44 a9 bc 71 de cf 59 d4 6e
                     : da 44 99 3c 21 64 e4 78 54 9d d0 7b ba 4e f5 18
                     : 4d 5e 39 30 bf e0 d1 f6 f4 83 25 4f 14 aa 71 e1



D.1.2 Pretty Print of "Self-Signed" Certificate

----------
decode: 0-OK, len=662 (662 bytes in file)

      Version: v3
Serial Number: 17



Housley, Ford, Polk, & Solo                                    [Page 98]


INTERNET DRAFT                                          October 14, 1997


Signature Alg: dsa-with-sha (1.2.840.10040.4.3)
       Issuer: C=US, O=gov, OU=nist
     Validity: from 970630000000Z
                 to 971231000000Z
      Subject: OU=nist, O=gov, C=US
SubjectPKInfo: dsa (1.2.840.10040.4.1)
       params:
        02 81 80 d4 38 02 c5 35 7b d5 0b a1 7e 5d 72 59
        63 55 d3 45 56 ea e2 25 1a 6b c5 a4 ab aa 0b d4
        62 b4 d2 21 b1 95 a2 c6 01 c9 c3 fa 01 6f 79 86
        83 3d 03 61 e1 f1 92 ac bc 03 4e 89 a3 c9 53 4a
        f7 e2 a6 48 cf 42 1e 21 b1 5c 2b 3a 7f ba be 6b
        5a f7 0a 26 d8 8e 1b eb ec bf 1e 5a 3f 45 c0 bd
        31 23 be 69 71 a7 c2 90 fe a5 d6 80 b5 24 dc 44
        9c eb 4d f9 da f0 c8 e8 a2 4c 99 07 5c 8e 35 2b
        7d 57 8d 02 14 a7 83 9b f3 bd 2c 20 07 fc 4c e7
        e8 9f f3 39 83 51 0d dc dd 02 81 80 0e 3b 46 31
        8a 0a 58 86 40 84 e3 a1 22 0d 88 ca 90 88 57 64
        9f 01 21 e0 15 05 94 24 82 e2 10 90 d9 e1 4e 10
        5c e7 54 6b d4 0c 2b 1b 59 0a a0 b5 a1 7d b5 07
        e3 65 7c ea 90 d8 8e 30 42 e4 85 bb ac fa 4e 76
        4b 78 0e df 6c e5 a6 e1 bd 59 77 7d a6 97 59 c5
        29 a7 b3 3f 95 3e 9d f1 59 2d f7 42 87 62 3f f1
        b8 6f c7 3d 4b b8 8d 74 c4 ca 44 90 cf 67 db de
        14 60 97 4a d1 f7 6d 9e 09 94 c4 0d
   Public Key:
        00 02 81 80 aa 98 ea 13 94 a2 db f1 5b 7f 98 2f
        78 e7 d8 e3 b9 71 86 f6 80 2f 40 39 c3 da 3b 4b
        13 46 26 ee 0d 56 c5 a3 3a 39 b7 7d 33 c2 6b 5c
        77 92 f2 55 65 90 39 cd 1a 3c 86 e1 32 eb 25 bc
        91 c4 ff 80 4f 36 61 bd cc e2 61 04 e0 7e 60 13
        ca c0 9c dd e0 ea 41 de 33 c1 f1 44 a9 bc 71 de
        cf 59 d4 6e da 44 99 3c 21 64 e4 78 54 9d d0 7b
        ba 4e f5 18 4d 5e 39 30 bf e0 d1 f6 f4 83 25 4f
        14 aa 71 e1
    issuerUID:
   subjectUID:
 1 extensions:
     Exten  1:   basicConstraints (2.5.29.19)
        30 00
Signature Alg: dsa-with-sha (1.2.840.10040.4.3)
    Sig Value: 368 bits:
        30 2c 02 14 a0 66 c1 76 33 99 13 51 8d 93 64 2f
        ca 13 73 de 79 1a 7d 33 02 14 5d 90 f6 ce 92 4a
        bf 29 11 24 80 28 a6 5a 8e 73 b6 76 02 68


------- extensions ----------



Housley, Ford, Polk, & Solo                                    [Page 99]


INTERNET DRAFT                                          October 14, 1997


printber -s 616 pkix-ex1.ber
get 0, len=46 (662 bytes in file)
0000 30 2c         44: SEQUENCE
0002 02 14         20: . INTEGER
                     : 9d 2d 0c 75 ec ce 01 79 25 4c cd 7b dc fc 17 0e
                     : 0f 2a 22 ef
0024 02 14         20: . INTEGER
                     : 80 61 6f fb dc 71 cf 3f 09 62 b4 aa ad 4b 8c 28
                     : 68 d7 60 fe



D.2 Certificate

   This section contains an annotated hex dump of a xxx byte version 3
   certificate.  The certificate contains the following information:
   (a) the serial number is 18 (12 hex);
   (b) the certificate is signed with DSA and the SHA-1 hash algorithm;
   (c) the issuer's distinguished name is OU=nist;O=gov;C=US
   (d) and the subject's distinguished name is CN=Tim
   Polk;OU=nist;O=gov;C=US
   (e) the certificate was valid from July 30, 1997 and will expire on
   December 1, 1997;
   (f) the certificate contains a 1024 bit DSA public key;
   (g) the certificate is an end entity certificate unless external
   information is provided, as the basic constraints extension is not
   present;
   (h) the certificate includes one alternative name - an RFC 822
   address.


D.2.1 Basic ASN.1 Dump of "End Entity" Certificate

----------

get 0, len=697 (697 bytes in file)
0000 30 82 02 b5  693: SEQUENCE
0004 30 82 02 75  629: . SEQUENCE
0008 a0 03          3: . . [0]
0010 02 01          1: . . . INTEGER 2
0013 02 01          1: . . INTEGER 18
0016 30 09          9: . . SEQUENCE
0018 06 07          7: . . . OID 1.2.840.10040.4.3: dsa-with-sha
0027 30 2a         42: . . SEQUENCE
0029 31 0b         11: . . . SET
0031 30 09          9: . . . . SEQUENCE
0033 06 03          3: . . . . . OID 2.5.4.6: C
0038 13 02          2: . . . . . PrintableString  'US'



Housley, Ford, Polk, & Solo                                   [Page 100]


INTERNET DRAFT                                          October 14, 1997


0042 31 0c         12: . . . SET
0044 30 0a         10: . . . . SEQUENCE
0046 06 03          3: . . . . . OID 2.5.4.10: O
0051 13 03          3: . . . . . PrintableString  'gov'
0056 31 0d         13: . . . SET
0058 30 0b         11: . . . . SEQUENCE
0060 06 03          3: . . . . . OID 2.5.4.11: OU
0065 13 04          4: . . . . . PrintableString  'nist'
0071 30 1e         30: . . SEQUENCE
0073 17 0d         13: . . . UTCTime  '970730000000Z'
0088 17 0d         13: . . . UTCTime  '971201000000Z'
0103 30 3d         61: . . SEQUENCE
0105 31 0b         11: . . . SET
0107 30 09          9: . . . . SEQUENCE
0109 06 03          3: . . . . . OID 2.5.4.6: C
0114 13 02          2: . . . . . PrintableString  'US'
0118 31 0c         12: . . . SET
0120 30 0a         10: . . . . SEQUENCE
0122 06 03          3: . . . . . OID 2.5.4.10: O
0127 13 03          3: . . . . . PrintableString  'gov'
0132 31 0d         13: . . . SET
0134 30 0b         11: . . . . SEQUENCE
0136 06 03          3: . . . . . OID 2.5.4.11: OU
0141 13 04          4: . . . . . PrintableString  'nist'
0147 31 11         17: . . . SET
0149 30 0f         15: . . . . SEQUENCE
0151 06 03          3: . . . . . OID 2.5.4.3: CN
0156 13 08          8: . . . . . PrintableString  'Tim Polk'
0166 30 82 01 b4  436: . . SEQUENCE
0170 30 82 01 29  297: . . . SEQUENCE
0174 06 07          7: . . . . OID 1.2.840.10040.4.1: dsa
0183 30 82 01 1c  284: . . . . SEQUENCE
0187 02 81 80     128: . . . . . INTEGER
                     : d4 38 02 c5 35 7b d5 0b a1 7e 5d 72 59 63 55 d3
                     : 45 56 ea e2 25 1a 6b c5 a4 ab aa 0b d4 62 b4 d2
                     : 21 b1 95 a2 c6 01 c9 c3 fa 01 6f 79 86 83 3d 03
                     : 61 e1 f1 92 ac bc 03 4e 89 a3 c9 53 4a f7 e2 a6
                     : 48 cf 42 1e 21 b1 5c 2b 3a 7f ba be 6b 5a f7 0a
                     : 26 d8 8e 1b eb ec bf 1e 5a 3f 45 c0 bd 31 23 be
                     : 69 71 a7 c2 90 fe a5 d6 80 b5 24 dc 44 9c eb 4d
                     : f9 da f0 c8 e8 a2 4c 99 07 5c 8e 35 2b 7d 57 8d
0318 02 14         20: . . . . . INTEGER
                     : a7 83 9b f3 bd 2c 20 07 fc 4c e7 e8 9f f3 39 83
                     : 51 0d dc dd
0340 02 81 80     128: . . . . . INTEGER
                     : 0e 3b 46 31 8a 0a 58 86 40 84 e3 a1 22 0d 88 ca
                     : 90 88 57 64 9f 01 21 e0 15 05 94 24 82 e2 10 90
                     : d9 e1 4e 10 5c e7 54 6b d4 0c 2b 1b 59 0a a0 b5



Housley, Ford, Polk, & Solo                                   [Page 101]


INTERNET DRAFT                                          October 14, 1997


                     : a1 7d b5 07 e3 65 7c ea 90 d8 8e 30 42 e4 85 bb
                     : ac fa 4e 76 4b 78 0e df 6c e5 a6 e1 bd 59 77 7d
                     : a6 97 59 c5 29 a7 b3 3f 95 3e 9d f1 59 2d f7 42
                     : 87 62 3f f1 b8 6f c7 3d 4b b8 8d 74 c4 ca 44 90
                     : cf 67 db de 14 60 97 4a d1 f7 6d 9e 09 94 c4 0d
0471 03 81 84     132: . . . BIT STRING  (0 unused bits)
                     : 02 81 80 a8 63 b1 60 70 94 7e 0b 86 08 93 0c 0d
                     : 08 12 4a 58 a9 af 9a 09 38 54 3b 46 82 fb 85 0d
                     : 18 8b 2a 77 f7 58 e8 f0 1d d2 18 df fe e7 e9 35
                     : c8 a6 1a db 8d 3d 3d f8 73 14 a9 0b 39 c7 95 f6
                     : 52 7d 2d 13 8c ae 03 29 3c 4e 8c b0 26 18 b6 d8
                     : 11 1f d4 12 0c 13 ce 3f f1 c7 05 4e df e1 fc 44
                     : fd 25 34 19 4a 81 0d dd 98 42 ac d3 b6 91 0c 7f
                     : 16 72 a3 a0 8a d7 01 7f fb 9c 93 e8 99 92 c8 42
                     : 47 c6 43
0606 a3 1d         29: . . [3]
0608 30 1b         27: . . . SEQUENCE
0610 30 19         25: . . . . SEQUENCE
0612 06 03          3: . . . . . OID 2.5.29.17: subjectAltName
0617 04 12         18: . . . . . OCTET STRING
                     : 30 10 81 0e 77 70 6f 6c 6b 40 6e 69 73 74 2e 67
                     : 6f 76
0637 30 09          9: . SEQUENCE
0639 06 07          7: . . OID 1.2.840.10040.4.3: dsa-with-sha
0648 03 2f         47: . BIT STRING  (0 unused bits)
                     : 30 2c 02 14 3c 02 e0 ab d9 5d 05 77 75 15 71 58
                     : 92 29 48 c4 1c 54 df fc 02 14 5b da 53 98 7f c5
                     : 33 df c6 09 b2 7a e3 6f 97 70 1e 14 ed 94

-------- extensions ----------

printber -s 475 pkix-ex2.ber
get 0, len=131 (697 bytes in file)
0000 02 81 80     128: INTEGER
                     : a8 63 b1 60 70 94 7e 0b 86 08 93 0c 0d 08 12 4a
                     : 58 a9 af 9a 09 38 54 3b 46 82 fb 85 0d 18 8b 2a
                     : 77 f7 58 e8 f0 1d d2 18 df fe e7 e9 35 c8 a6 1a
                     : db 8d 3d 3d f8 73 14 a9 0b 39 c7 95 f6 52 7d 2d
                     : 13 8c ae 03 29 3c 4e 8c b0 26 18 b6 d8 11 1f d4
                     : 12 0c 13 ce 3f f1 c7 05 4e df e1 fc 44 fd 25 34
                     : 19 4a 81 0d dd 98 42 ac d3 b6 91 0c 7f 16 72 a3
                     : a0 8a d7 01 7f fb 9c 93 e8 99 92 c8 42 47 c6 43


D.2.2 Pretty Print of "End Entity" Certificate

----------
decode: 0-OK, len=697 (697 bytes in file)



Housley, Ford, Polk, & Solo                                   [Page 102]


INTERNET DRAFT                                          October 14, 1997


      Version: v3
Serial Number: 18
Signature Alg: dsa-with-sha (1.2.840.10040.4.3)
       Issuer: C=US, O=gov, OU=nist
     Validity: from 970730000000Z
                 to 971201000000Z
      Subject: CN=Tim Polk, OU=nist, O=gov, C=US
SubjectPKInfo: dsa (1.2.840.10040.4.1)
       params:
        02 81 80 d4 38 02 c5 35 7b d5 0b a1 7e 5d 72 59
        63 55 d3 45 56 ea e2 25 1a 6b c5 a4 ab aa 0b d4
        62 b4 d2 21 b1 95 a2 c6 01 c9 c3 fa 01 6f 79 86
        83 3d 03 61 e1 f1 92 ac bc 03 4e 89 a3 c9 53 4a
        f7 e2 a6 48 cf 42 1e 21 b1 5c 2b 3a 7f ba be 6b
        5a f7 0a 26 d8 8e 1b eb ec bf 1e 5a 3f 45 c0 bd
        31 23 be 69 71 a7 c2 90 fe a5 d6 80 b5 24 dc 44
        9c eb 4d f9 da f0 c8 e8 a2 4c 99 07 5c 8e 35 2b
        7d 57 8d 02 14 a7 83 9b f3 bd 2c 20 07 fc 4c e7
        e8 9f f3 39 83 51 0d dc dd 02 81 80 0e 3b 46 31
        8a 0a 58 86 40 84 e3 a1 22 0d 88 ca 90 88 57 64
        9f 01 21 e0 15 05 94 24 82 e2 10 90 d9 e1 4e 10
        5c e7 54 6b d4 0c 2b 1b 59 0a a0 b5 a1 7d b5 07
        e3 65 7c ea 90 d8 8e 30 42 e4 85 bb ac fa 4e 76
        4b 78 0e df 6c e5 a6 e1 bd 59 77 7d a6 97 59 c5
        29 a7 b3 3f 95 3e 9d f1 59 2d f7 42 87 62 3f f1
        b8 6f c7 3d 4b b8 8d 74 c4 ca 44 90 cf 67 db de
        14 60 97 4a d1 f7 6d 9e 09 94 c4 0d
   Public Key:
        00 02 81 80 a8 63 b1 60 70 94 7e 0b 86 08 93 0c
        0d 08 12 4a 58 a9 af 9a 09 38 54 3b 46 82 fb 85
        0d 18 8b 2a 77 f7 58 e8 f0 1d d2 18 df fe e7 e9
        35 c8 a6 1a db 8d 3d 3d f8 73 14 a9 0b 39 c7 95
        f6 52 7d 2d 13 8c ae 03 29 3c 4e 8c b0 26 18 b6
        d8 11 1f d4 12 0c 13 ce 3f f1 c7 05 4e df e1 fc
        44 fd 25 34 19 4a 81 0d dd 98 42 ac d3 b6 91 0c
        7f 16 72 a3 a0 8a d7 01 7f fb 9c 93 e8 99 92 c8
        42 47 c6 43
    issuerUID:
   subjectUID:
 1 extensions:
     Exten  1:   subjectAltName (2.5.29.17)
        30 10 81 0e 77 70 6f 6c 6b 40 6e 69 73 74 2e 67
        6f 76
Signature Alg: dsa-with-sha (1.2.840.10040.4.3)
    Sig Value: 368 bits:
        30 2c 02 14 3c 02 e0 ab d9 5d 05 77 75 15 71 58
        92 29 48 c4 1c 54 df fc 02 14 5b da 53 98 7f c5
        33 df c6 09 b2 7a e3 6f 97 70 1e 14 ed 94



Housley, Ford, Polk, & Solo                                   [Page 103]


INTERNET DRAFT                                          October 14, 1997


-------- extensions ----------

printber -s 619 pkix-ex2.ber
get 0, len=18 (697 bytes in file)
0000 30 10         16: SEQUENCE
0002 81 0e         14: . [1]
                     : 77 70 6f 6c 6b 40 6e 69 73 74 2e 67 6f 76
Note: This subjectAltName data is IMPLICIT TAGS - is that correct?

printber -s 651 pkix-ex2.ber
get 0, len=46 (697 bytes in file)
0000 30 2c         44: SEQUENCE
0002 02 14         20: . INTEGER
                     : 2b 82 c9 2d 79 9c a4 16 97 22 b1 48 16 03 c2 ed
                     : 31 65 99 d5
0024 02 14         20: . INTEGER
                     : 3f 90 79 17 f8 9d 50 fb f3 5d 70 b7 40 31 a3 74
                     : 31 d7 b1 30

D.3 End-Entity Certificate Using RSA

   This section contains an annotated hex dump of a 675 byte version 3
   certificate.  The certificate contains the following information:
   (a) the serial number is 2;
   (b) the certificate is signed with RSA and the MD5 hash algorithm;
   (c) the issuer's distinguished name is OU=esCert-
   UPC;O=UPC;L=Barcelona;STREET=Catalunya;C=ES
   (d) and the subject's distinguished name is
   CN=escert.upc.es;OU=esCert-
   UPC;O=UPC;L=Barcelona;STREET=Catalunya;C=ES
   (e) the certificate was issued on May 21, 1996 and will expire on May
   21, 1997;
   (f) the certificate contains a 768 bit RSA public key which is
   intended for generation of digital signatures;
   (g) the certificate is an end entity certificate (not a CA
   certificate);
   (h) the certificate includes two alternative names - an RFC 822
   address, and a URL.

 sequence length 029f=671 bytes
 30 82 02 9f
    sequence length 0208h=520 bytes
    30 82 02 08
       explicit tag 00 "Version"
       a0 03
          integer length 1 value 2 [version is 3]
          02 01 02
       integer length 1 value 2 [serial number 2]



Housley, Ford, Polk, & Solo                                   [Page 104]


INTERNET DRAFT                                          October 14, 1997


       02 01 02
       sequence length 13 [signature]
       30 0d
          object identifier length 9 {1 2 840 113549 1 1 4}
                                {iso(1) member-body(2) us(840) etc.}
          06 09 2a 86 48 86 f7 0d 01 01 04
          null [null parameters]
          05 00
       sequence length 88 [issuer]
          30 58
             RDN length 11
             31 0b
                sequence length 9
                30 09
                   object identifier length 3  { 2 5 4 6 }
                   06 03 55 04 06
                   printable string length 2 "ES"
                   13 02 45 53
             RDN length 18
             31 12
                sequence length 16
                30 10
                   object identifier length 3 { 2 5 4 9 }
                   06 03 55 04 09
                   printable string length 9 "Catalunya"
                   13 09 43 61 74 61 6c 75 6e 79 61
             RDN length 18
             31 12
                sequence length 16
                30 10
                   object identifier length 3 { 2 5 4 7 }
                   06 03 55 04 07
                   printable string length 9 "Barcelona"
                   13 09 42 61 72 63 65 6c 6f 6e 61
             RDN length 12
             31 0c
                sequence length 10
                30 0a
                   object identifier {2 5 4 10 }
                   06 03 55 04 0a
                   printable string length 3 "UPC"
                   13 03 55 50 43
             RDN length 19
             31 13
                sequence length 17
                30 11
                   object identifier {2 5 4 13 }
                   06 03 55 04 0b



Housley, Ford, Polk, & Solo                                   [Page 105]


INTERNET DRAFT                                          October 14, 1997


                   printable string length 10 "esCERT-UPC"
                   13 0a 65 73 43 45 52 54 2d 55 50 43
       sequence length 0x1e= 30
          30 1e
             UTCTime "960521095826Z"
             17 0d 39 36 30 35 32 31 30 39 35 38 32 36 5a
             UTCTime "979521095826Z"
             17 0d 39 37 30 35 32 31 30 39 35 38 32 36 5a
       sequence length
       30 70
          31 0b
             30 09
                { 2 5 4 6 }
                06 03 55 04 06
                "ES"
                13 02 45 53
          RDN
          31 12
             30 10
                { 2 5 4 9 }
                06 03 55 04 09
                "Catalunya"
                13 09 43 61 74 61 6c 75 6e 7961
          RDN
          31 12
             30 10
                { 2 5 4 7 }
                06 03 55 04 07
                "Barcelona"
                13 09 42 61 72 63 65 6c 6f 6e 61
          RDN
          31 0c
             30 0a
                { 2 5 4 10 }
                06 03 55 04 0a
                "UPC"
                13 03 55 50 43
          RDN
          31 13
             30 11
                { 2 5 4 11 }
                06 03 55 04 0b
                "esCERT-UPC"
                13 0a 65 73 43 45 52 54 2d 55 50 43
          RDN
          31 16
             30 14
                { 2 5 4 3 }



Housley, Ford, Polk, & Solo                                   [Page 106]


INTERNET DRAFT                                          October 14, 1997


                06 03 55 04 03
                "escert.upc.es"
                13 0d 65 73 63 65 72 74 2e 75 70 63 2e 65 73
        subjectPublicKeyInfo
          30 7c
             algorithmIdentifier
             30 0d
                { 1 2 840 113549 1 1 1}
                06 09 2a 86 48 86 f7 0d 01 01 01
                null parameters
                05 00
             { subject's public key }
             03 6b  BIT STRING length 107 bytes (856 bits)
                               0030 6802 6100 beaa 8b77 54a3 afca 779f
                               2fb0 cf43 88ff a66d 7955 5b61 8c68 ec48
                               1e8a 8638 a4fe 19b8 6217 1d9d 0f47 2cff
                               638f 2991 04d1 52bc 7f67 b6b2 8f74 55c1
                               3321 6c8f ab01 9524 c8b2 7393 9d22 6150
                               a935 fb9d 5750 32ef 5652 5093 abb1 8894
                               7856 15c6 1c8b 0203 0100 01
         explicit tag 3 "extensions" length 0x84=132
         a3 81 84
            sequence 129 bytes
            30 81 81
               sequence 12 bytes
               30 0b
                  id-ce-keyUsage = { 2 5 29 15 }
                  06 03 55 1d 0f
                  by default, critical = FALSE
                  octet string
                  04 04 03 02 07 80
               30 09
                  id-ce-basicConstraints = { 2 5 29 19 }
                  06 03 55 1d 13
                  by default, critical = FALSE
                  octet string
                  04 02
                     null sequence - by default, subject is end entity
                     30 00
               30 3d
                  id-ce-subjectAltName = { 2 5 29 17 }
                  06 03 55 1d 11
                  by default, critical = FALSE
                  octet string
                  04 36
                     30 34
                        rfc822name
                        a1 1a



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                           IA5String "escert-upc@escert.upc.es"
                           16 18 65 73 63 65 72 74 2d 75 70 63 40 65 73 63
                           65 72 74 2e 75 70 63 2e 65 73
                        uniformResourceIdentifier
                        a6 16
                           IA5String "http://escert.upc.es"
                           16 14 68 74 74 70 3a 2f 2f 65 73 63 65 72 74 2e
                           75 70 63 2e 65 73
               30 28
                  id-ce-certificatePolicies = { 2 5 29 32 }
                  06 03 55 1d 20
                  by default, critical = FALSE
                  octet string
                  04 21
                     30 1f
                        30 1d
                           06 04 2a 84 80 00
                           { 2 2 32768 }
                     30 15
                        30 07
                           { 2 2 32768 1 }
                           06 05 2a 84 80 00 01
                         30 0a
                            { 2 2 32768 2 }
                            06 05 2a 84 80 00 02
                            02 01 0a
   sequence
   30 0d
      { 1 2 840 113549 1 1 4 }
      06 09 2a 86 48 86 f7 0d 01 01 04
      null parameters
      05 00
   bit string length 129  (signature)
   03 81 81 005b fdc2 a704 d483 4e17 6da6 fa27 e7c6
            f8ab b95d 9fd0 a1df d797 9fe0 20a6 c57a
            64cd 522f e9ae dabe 9ce4 d597 edf1 84c0
            d0fe 9bef 54b1 80e5 bf3c c9ed 9320 2d52
            21e9 bcb9 e34f ac11 650e 8fa1 6899 6347
            e53d e442 7313 fac5 c834 8cc0 4118 89d5
            e6a0 185b 5d86 1c1e c670 d80e 8964 9483
            8e3b 407c 59cf 2b2f b7ce 9798 1215 ef13
            d4


D.4 Certificate Revocation List

   This section contains an annotated hex dump of a version 2 CRL with
   one extension (cRLNumber). The CRL was issued by OU=nist;O=gov;C=us



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   on July 7, 1996; the next scheduled issuance was August 7, 1996.  The
   CRL includes one revoked certificates: serial number 18 (12 hex).
   The CRL itself is number 18, and it was signed with DSA.

printber pkix-crl.ber
get 0, len=189 (189 bytes in file)
0000 30 81 ba     186: SEQUENCE
0003 30 7c        124: . SEQUENCE
0005 02 01          1: . . INTEGER 1
0008 30 09          9: . . SEQUENCE
0010 06 07          7: . . . OID 1.2.840.10040.4.3: dsa-with-sha
0019 30 2a         42: . . SEQUENCE
0021 31 0b         11: . . . SET
0023 30 09          9: . . . . SEQUENCE
0025 06 03          3: . . . . . OID 2.5.4.6: C
0030 13 02          2: . . . . . PrintableString  'US'
0034 31 0c         12: . . . SET
0036 30 0a         10: . . . . SEQUENCE
0038 06 03          3: . . . . . OID 2.5.4.10: O
0043 13 03          3: . . . . . PrintableString  'gov'
0048 31 0d         13: . . . SET
0050 30 0b         11: . . . . SEQUENCE
0052 06 03          3: . . . . . OID 2.5.4.11: OU
0057 13 04          4: . . . . . PrintableString  'nist'
0063 17 0d         13: . . UTCTime  '970801000000Z'
0078 17 0d         13: . . UTCTime  '970808000000Z'
0093 30 22         34: . . SEQUENCE
0095 30 20         32: . . . SEQUENCE
0097 02 01          1: . . . . INTEGER 18
0100 17 0d         13: . . . . UTCTime  '970731000000Z'
0115 30 0c         12: . . . . SEQUENCE
0117 30 0a         10: . . . . . SEQUENCE
0119 06 03          3: . . . . . . OID 2.5.29.21: reasonCode
0124 04 03          3: . . . . . . OCTET STRING
                     : 0a 01 01
0129 30 09          9: . SEQUENCE
0131 06 07          7: . . OID 1.2.840.10040.4.3: dsa-with-sha
0140 03 2f         47: . BIT STRING  (0 unused bits)
                     : 30 2c 02 14 9e d8 6b c1 7d c2 c4 02 f5 17 84 f9
                     : 9f 46 7a ca cf b7 05 8a 02 14 9e 43 39 85 dc ea
                     : 14 13 72 93 54 5d 44 44 e5 05 fe 73 9a b2


printber -s 143 pkix-crl.ber
get 0, len=46 (189 bytes in file)
0000 30 2c         44: SEQUENCE
0002 02 14         20: . INTEGER
                     : 9e d8 6b c1 7d c2 c4 02 f5 17 84 f9 9f 46 7a ca



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                     : cf b7 05 8a
0024 02 14         20: . INTEGER
                     : 9e 43 39 85 dc ea 14 13 72 93 54 5d 44 44 e5 05
                     : fe 73 9a b2


Security Considerations

   This entire memo is about security mechanisms.

Author Addresses:

   Russell Housley
   SPYRUS
   PO Box 1198
   Herndon, VA 20172
   USA
   housley@spyrus.com

   Warwick Ford
   VeriSign, Inc.
   One Alewife Center
   Cambridge, MA 02140
   USA
   wford@verisign.com

   Tim Polk
   NIST
   Building 820, Room 426
   Gaithersburg, MD 20899
   USA
   wpolk@nist.gov

   David Solo
   BBN
   150 CambridgePark Drive
   Cambridge, MA 02140
   USA
   solo@bbn.com












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