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Versions: (draft-pritikin-est) 00 01 02 03 06 07 08 09 RFC 7030

PKIX                                                    M. Pritikin, Ed.
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                             P. Yee, Ed.
Expires: January 11, 2013                                   AKAYLA, Inc.
                                                         D. Harkins, Ed.
                                                          Aruba Networks
                                                           July 10, 2012


                    Enrollment over Secure Transport
                         draft-ietf-pkix-est-02

Abstract

   This document profiles certificate enrollment for clients using
   Certificate Management over CMS (CMC) messages over a secure
   transport.  This profile, called Enrollment over Secure Transport
   (EST), describes a simple yet functional certificate management
   protocol targeting simple Public Key Infrastructure clients that need
   to acquire client certificate(s) and associated Certification
   Authority (CA) certificate(s).

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 11, 2013.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents



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   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Requirements Language  . . . . . . . . . . . . . . . . . .  5
   2.  Operational Scenario Overviews . . . . . . . . . . . . . . . .  5
     2.1.  Obtaining CA Certificates  . . . . . . . . . . . . . . . .  6
     2.2.  Initial Enrollment . . . . . . . . . . . . . . . . . . . .  6
       2.2.1.  Previously Installed Signature Certificate . . . . . .  7
       2.2.2.  Username/Password Distributed Out-of-Band  . . . . . .  7
       2.2.3.  RA Authentiation . . . . . . . . . . . . . . . . . . .  7
     2.3.  Re-Enrollment  . . . . . . . . . . . . . . . . . . . . . .  7
       2.3.1.  Re-Enrollment of Signature Certificates  . . . . . . .  7
       2.3.2.  Re-Enrollment of Key Establishment Certificates  . . .  8
     2.4.  Server Key Generation  . . . . . . . . . . . . . . . . . .  8
     2.5.  Full CMC messages  . . . . . . . . . . . . . . . . . . . .  8
     2.6.  CSR Attributes Request . . . . . . . . . . . . . . . . . .  8
   3.  Protocol Design and Layering . . . . . . . . . . . . . . . . .  8
     3.1.  Application Layer Design . . . . . . . . . . . . . . . . . 11
     3.2.  HTTP Layer Design  . . . . . . . . . . . . . . . . . . . . 12
       3.2.1.  HTTP headers for control . . . . . . . . . . . . . . . 12
       3.2.2.  HTTP URIs for control  . . . . . . . . . . . . . . . . 13
       3.2.3.  HTTP-Based Client Authentication . . . . . . . . . . . 14
       3.2.4.  Message types  . . . . . . . . . . . . . . . . . . . . 15
     3.3.  TLS Layer Design . . . . . . . . . . . . . . . . . . . . . 16
       3.3.1.  TLS for transport security . . . . . . . . . . . . . . 16
         3.3.1.1.  TLS-Based Server Authentication  . . . . . . . . . 16
         3.3.1.2.  TLS-Based Client Authentication  . . . . . . . . . 17
     3.4.  Proof-of-Possession  . . . . . . . . . . . . . . . . . . . 17
     3.5.  Linking Identity and POP information . . . . . . . . . . . 18
   4.  Protocol Exchange Details  . . . . . . . . . . . . . . . . . . 19
     4.1.  Server Authorization . . . . . . . . . . . . . . . . . . . 19
     4.2.  Client Authorization . . . . . . . . . . . . . . . . . . . 20
     4.3.  Distribution of CA certificates  . . . . . . . . . . . . . 20
       4.3.1.  Distribution of CA certificates response . . . . . . . 21
     4.4.  Simple Enrollment of Clients . . . . . . . . . . . . . . . 22
       4.4.1.  Simple Re-Enrollment of Clients  . . . . . . . . . . . 23
       4.4.2.  Simple Enroll and Re-Enroll Response . . . . . . . . . 24
     4.5.  Full CMC . . . . . . . . . . . . . . . . . . . . . . . . . 24
       4.5.1.  Full CMC Request . . . . . . . . . . . . . . . . . . . 25
       4.5.2.  Full CMC Response  . . . . . . . . . . . . . . . . . . 25
     4.6.  Server-side Key Generation . . . . . . . . . . . . . . . . 26



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       4.6.1.  Server-side Key Generation Request . . . . . . . . . . 26
       4.6.2.  Server-side Key Generation Response  . . . . . . . . . 26
     4.7.  CSR Attributes . . . . . . . . . . . . . . . . . . . . . . 27
       4.7.1.  CSR Attributes Request . . . . . . . . . . . . . . . . 27
       4.7.2.  CSR Attributes Response  . . . . . . . . . . . . . . . 27
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 28
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 30
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 32
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 32
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 33
   Appendix A.  Server Discovery  . . . . . . . . . . . . . . . . . . 34
   Appendix B.  External TLS concentrator . . . . . . . . . . . . . . 34
   Appendix C.  CGI Server implementation . . . . . . . . . . . . . . 35
   Appendix D.  Operational Scenario Example Messages . . . . . . . . 35
     D.1.  Obtaining CA Certificates  . . . . . . . . . . . . . . . . 35
     D.2.  Previously Installed Signature Certificate . . . . . . . . 36
     D.3.  Username/Password Distributed Out-of-Band  . . . . . . . . 38
     D.4.  Re-Enrollment  . . . . . . . . . . . . . . . . . . . . . . 41
     D.5.  Server Key Generation  . . . . . . . . . . . . . . . . . . 42
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 46































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1.  Introduction

   This document specifies a protocol for certificate Enrollment over
   Secure Transport (EST).  EST is designed to be easily implemented by
   clients and servers using common "off the shelf" PKI, HTTP, and TLS
   components.  An EST server providing certificate management functions
   is operated by (or on behalf of) a CA or RA.  The goal is to provide
   a small set of functions for certificate enrollment that are simpler
   to implement and use than full CMP or CMC.  While less functional
   than those protocols, EST satisfies basic needs by providing an
   easily implemented means for both autonomous devices as well as user-
   operated computers to request certificates.

   The TLS [RFC4346] (or later) protocol is used with a limited set of
   features of the Certificate Management over CMS (CMC) [RFC5272] to
   provide the security for EST.  CMC "simple" messages are used for
   certificate requests and responses.  EST also allows the optional use
   of "full" CMC messages if needed, but compliant EST client and server
   implementations need not support full CMC messages.  EST adopts the
   CMP model for CA certificate rollover, but does not incorporate its
   syntax or protocol.  An EST server supports several means of
   authenticating a certificate requester, leveraging the layering of
   the protocols that make up EST.  EST servers are extensible in that
   new requests may be defined which provide additional capabilities not
   specified in the base RFC.  One non-CMC-based extension (requesting
   of CSR attributes) is defined in this document.

   EST works by transporting CMC and other messages securely over an
   HTTPS transport in which HTTP headers and content types are used in
   conjunction with TLS security.  TCP/IP sits under HTTPS; this
   document does not specify EST over DTLS or UDP.  Figure 1 shows how
   the layers build upon each other.



















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   EST Layering:

   Protocols:
   +---------------------------------------------------+
   |                                                   |
   | 4) EST messages for requests/responses            |
   |                                                   |
   +---------------------------------------------------+
   |                                                   |
   | 3) HTTP for message carriage and signaling        |
   |                                                   |
   +---------------------------------------------------+
   |                                                   |
   | 2) TLS for transport security                     |
   |                                                   |
   +---------------------------------------------------+
   |                                                   |
   | 1) TCP/IP                                         |
   |                                                   |
   +---------------------------------------------------+

                                 Figure 1

   [[EDNOTE: Comments such as this one, included within double brackets
   and initiated with an 'EDNOTE', are for editorial use and shall be
   removed as the document is polished.]]

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].


2.  Operational Scenario Overviews

   This EST specification provides a profile of CMC using round-trip
   communication between the EST client and the EST server in which CMC
   "simple" messages are transmitted.  The basic framework can be
   extended with additional capabilities that leverage the transport and
   security features supplied by EST.

   The EST server is assumed to be configured with an identity
   certificate and appropriate policy regarding authenticated clients.
   An EST server likely communicates with a CA for signing but for
   simplicity we indicate that a' certificate is signed' as if by the
   EST server.  The EST client is initially configured with only the
   HTTPS URI of the EST server.



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   This section illustrates several potential certificate enrollment and
   rekey scenarios supported by this profile.  For clarity the EST
   client is assumed to perform "Obtaining CA Certificates" before
   performing other operations.

   This section does not intend to place any limits or restrictions on
   the use of full CMC.  Sections 2.1-2.3 very closely mirror the exact
   text of the Scenarios Appendix of [RFC6403] with such modifications
   as are appropriate for this profile.  (Our thanks are extended to the
   authors of that document).

2.1.  Obtaining CA Certificates

   The EST client can request a copy of the current CA certificates.

   Following the logic laid out in Section 3.3.1.1 the EST client
   authenticates and authorizes the EST server.  Available options
   include verifying the EST server URI against the EST server
   certificate (similar to a common HTTPS exchange), or using a "pinned"
   copy of the CA certificate.  As a fallback the EST client can accept
   manual authentication performed by the end user (in which case the
   certificates received are be "pinned" for authenticating future
   communications with the EST server).

   Client authentication is not required for this exchange so it is
   trivially serviced by the EST server.

2.2.  Initial Enrollment

   The EST client can enroll with the CA server by submitting an
   enrollment request to the EST server.  Following the logic laid out
   in Section 3.3.1.1 the EST client authenticates and authorizes the
   EST server.

   Three scenarios for the EST server to authenticate the enrollment
   requests are:

   1.  Previously installed signature certificate (e.g., Manufacturer
       Installed Certificate or 3rd party issued certificate);

   2.  Username/password distributed out-of-band

   3.  RA authentication








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2.2.1.  Previously Installed Signature Certificate

   If the EST client has a previously installed signature certificate
   issued by a trust anchor listed by the EST server during the TLS
   handshake it can be used to authenticate the request for a new
   certificate.  The EST client responds to the TLS certificate request
   with the existing certificate as defined for TLS.  The EST server
   will recognize the authorization of the previously installed
   certificate and issue an appropriate certificate to the EST client.

2.2.2.  Username/Password Distributed Out-of-Band

   If the EST client did not have a previously installed signature
   certificate, or if the EST server wishes additional authentication
   information, the EST server requests the EST client submit a
   username/password using the HTTP authentication methods.

2.2.3.  RA Authentiation

   In this scenario the EST client submits the certification request
   using either the /simpleEnroll or /fullCMC method.  The EST server
   forwards the received request using either CMC or other methods out-
   of-scope of this document.

2.3.  Re-Enrollment

   The EST client can renew/rekey an existing client certificate by
   submitting a re-enrollment request to the EST server.  As for initial
   enrollment the EST server authenticates the client using any
   combination of the existing client certificate and an HTTP username/
   password.  Because the client specifically requests renew/rekey the
   EST server can adjust its policy accordingly.

   There are two scenarios to support the renew/rekey of clients that
   are already enrolled.  One addresses the renew/rekey of signature
   certificates and the other addresses the renew/rekey of key
   establishment certificates.  Typically, organizational policy will
   require certificates to be currently valid to be renewed/rekeyed, and
   it may require initial enrollment to be repeated when renew/rekey is
   not possible.

2.3.1.  Re-Enrollment of Signature Certificates

   When a signature certificate is re-enrolled the existing certificate
   is used by the EST client for authentication.  The EST server uses
   this information along with any supplimental HTTP authentication
   information and the certification request itself to determine the
   parameters of the certificate to issue in response.  If there is no



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   current signature certificate available the EST server can fallback
   on the HTTP authentication method.  The certification request message
   will include the same Subject/SubjectAltName as the current signature
   certificate.

2.3.2.  Re-Enrollment of Key Establishment Certificates

   When a key establishment certificate is re-enrolled an existing
   signature certificate is used by the EST client for authentication.
   The EST server uses this information along with any supplimental HTTP
   authentication information and the certification request itself to
   determine the parameters of the certificate to issue in response.  If
   there is no current signature certificate available the EST server
   can fallback on the HTTP authentication method.  The certification
   request message will include the same Subject/SubjectAltName as the
   current key establishment certificate.

2.4.  Server Key Generation

   The EST client can request a server generated certificate and
   keypair.  The EST server authenticates the client using any existing
   client signature certificate and/or HTTP username/password.

2.5.  Full CMC messages

   Full CMC messages can be transported thus allowing access to
   functionality not provided by the simple CMC message.  "Full" CMC
   messages are as defined in Sections 3.2 and 4.2 of [RFC5272].
   Support for full CMC message transport is optional for EST clients
   and servers.

2.6.  CSR Attributes Request

   Prior to sending an enrollment request to an EST server, an EST
   client may request that the EST server send it a (set of) additional
   attribute(s) that the client is requested to supply in the subsequent
   enrollment (certificate signing) request.


3.  Protocol Design and Layering

   The following provides an expansion of Figure 1 describing how the
   layers are used.  Each aspect is described in more detail in the
   sections below.







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   EST Layering:

   Protocols and uses:
   +----------------------------------------------------+
   |                                                    |
   | 3) Message types:                                  |
   |    - CMC "Simple PKI" messages                     |
   |      (incorporating proof-of-possession)           |
   |    - CA certificate retrieval                      |
   |    - "Full" CMC messages (optional)                |
   |    - CSR attribute request (optional)              |
   |                                                    |
   +----------------------------------------------------+
   |                                                    |
   | 2) HTTP:                                           |
   |    - HTTP headers and URIs for control             |
   |       - Content-Type headers specify message type  |
   |       - Headers for control/error messages         |
   |       - URIs for selecting operations              |
   |    - Basic authentication if no TLS client cert    |
   |                                                    |
   +----------------------------------------------------+
   |                                                    |
   | 1) TLS for transport security                      |
   |    - Authentication for EST server and optionally  |
   |      EST client                                    |
   |    - Indirectly provides proof-of-identity for EST |
   |    - Communications integrity                      |
   |    - "Channel binding" to link proof-of-identity   |
   |      with message based proof-of-possession.       |
   |      (optional)                                    |
   |                                                    |
   +----------------------------------------------------+

                                 Figure 2

   Specifying HTTPS as the secure transport for PKI enrollment messages
   introduces two 'layers' for communication of authentication and
   control messages during the protocol exchange: TLS and HTTP.

   The TLS layer provides message authentication and integrity during
   transport.  The proof-of-identity is supplied by either the
   certificate exchange during the TLS handshake or within the HTTP
   layer headers.  The message type along with control/error messages
   are included in the HTTP headers.

   The TLS and HTTP layer provided proof-of-identity means the CMC
   [RFC5272] Section 3.1 note that "the Simple PKI Request MUST NOT be



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   used if a proof-of-identity needs to be included" is not applicable
   and thus the "Simple PKI" message types are used.

   The TLS layer certificate exchange provides a method for authorizing
   client enrollment requests using existing certificates.  Such
   existing certificates may have been issued by the Certification
   Authority (CA) (from which the client is requesting a certificate) or
   they may have been issued under a distinct PKI (e.g., an IEEE 802.1AR
   IDevID [IDevID] credential).

   Proof-of-possession is a distinct issue from proof-of-identity and is
   included in the "Simple PKI" message type as described in
   Section 3.4.  A method of linking proof-of-identiy and proof-of-
   posession is described in Section 3.5.

   This document also defines transport for the full CMC [RFC5272]
   specification compliant with CMC Transport Protocols [RFC5273].

   During the protocol operations various different certificates can be
   used.  The following table provides an informative overview.  End
   entities MAY have one or more certificates of each type as is
   appropriate:





























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   Certificates/Trust-anchors and their corresponding uses:
   +--------------+--------------------+------------------------------+
   | End Entity   | Issuer             | Use                          |
   +==============+====================+==============================+
   | EST server   | The CA served by   | To authenticate              |
   |              | the EST server     | servers that have certs      |
   |              |                    | issued by the CA             |
   |              |                    | Section: 3.3.1.1.            |
   +--------------+--------------------+------------------------------+
   | EST server   | An unrelated CA    | To authenticate              |
   |              | e.g., a Web site   | servers that have certs      |
   |              | CA                 | issued by Web site CAs       |
   |              |                    | Section: 3.3.1.1.            |
   +--------------+--------------------+------------------------------+
   | EST client   | Trust anchors for  | EST clients can leverage     |
   | Trust Anchor | third party CAs    | a trust anchor database to   |
   | Database     | e.g., a list of    | authenticate EST servers     |
   |              | Web site CA root   | using a configured URI       |
   |              | certs              | Section: 3.3.1.1             |
   +--------------+--------------------+------------------------------+
   | EST client   | An unrelated CA    | To authenticate clients      |
   |              | e.g., a device     | that have not yet enrolled   |
   |              | manufacturer       | Section: 3.3.1.2             |
   +--------------+--------------------+------------------------------+
   | EST client   | The CA served by   | To authenticate clients      |
   |              | the EST server     | that have already enrolled   |
   |              |                    | (for re-enroll or obtaining  |
   |              |                    | additional certs)            |
   |              |                    | Section: 3.3.1.2             |
   +--------------+--------------------+------------------------------+
   | EST client   | The CA served by   | Clients can obtain certs     |
   |              | the EST server     | that can not be used for     |
   |              |                    | EST authentication           |
   |              |                    | (e.g., Key Encryption certs) |
   |              |                    | Section: 4.4.1               |
   +--------------+--------------------+------------------------------+


                                 Figure 3

3.1.  Application Layer Design

   An EST client SHOULD have its own client certificate suitable for TLS
   client authentication (e.g., the digitalSignature bit is set).  The
   client certificate, if available, is used when authenticating to the
   EST server.  This certificate MAY also be used by the client with
   other certificate consuming protocols.  If a client does not have a
   certificate, then the client MUST have HTTP Basic or Digest



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   authentication credentials (see Section 3.2.3).  HTTP authentication
   provides a bootstrap for clients that have not yet been issued an
   initial certificate.  EST clients obtaining a certificates for other
   protocol purposes are RECOMMENDED to first obtain an appropropriate
   digitalSignature certificate for use when authenticating to the EST
   server.

   The client also SHOULD also have a CA certificate that will be used
   to authenticate the EST server.

   An EST client MUST be capable of generating and parsing simple CMC
   messages (see Section 4.4).  Generating and parsing full CMC messages
   is optional (see Section 4.5).  The client MUST also be able to
   request CA certificates from the EST server and parse the returned
   "bag" of certificates (see Section 4.3).  Requesting CSR attributes
   and parsing the returned list of attributes is optional (see
   Section 4.7).

3.2.  HTTP Layer Design

   HTTP is used to transport EST requests and responses.  Specific URIs
   are provisioned for handling each type of request as described in
   Section 3.2.2.  HTTP is also used for client authentication services
   when TLS client authentication is not available due to lack of a
   client certificate suitable for use by TLS, as detailed in Section
   Section 3.2.3.  HTTP message types are used to convey EST requests
   and responses as specified in Figure 5.

3.2.1.  HTTP headers for control

   This document profiles the HTTP content-type header (as defined in
   [RFC2046], but see Figure 5 for specific values ) to indicate the
   message type for EST messages and to specify EST control messages.
   The HTTP Status value is used to communicate success or failure of
   control messages.  Support for the HTTP username/password methods is
   profiled for when a client does not have a suitable client
   certificate.

   CMC does not provide specific messages for certificate renewal and
   certificate rekey.  This profile defines the renewal and rekey
   behavior of both the client and server.  It does so by specifying the
   HTTP control mechanisms employed by the client and server without
   requiring a new CMC message type.

   Various media types as indicated in the HTTP content-type header are
   used to transport EST messages.  Valid media types are specified in
   Section 3.2.4.




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3.2.2.  HTTP URIs for control

   This profile supports four operations indicated by specific URIs:

   Operations and their corresponding URIs:
   +------------------------+-----------------+-------------------+
   | Operation              |Operation Path   | Details           |
   +========================+=================+===================+
   | Distribution of CA     | /CACerts        | Section 4.3       |
   | certificates           |                 |                   |
   +------------------------+-----------------+-------------------+
   | Enrollment of new      | /simpleEnroll   | Section 4.4       |
   | clients                |                 |                   |
   +------------------------+-----------------+-------------------+
   | Re-Enrollment of       | /simpleReEnroll | Section 4.4.1     |
   | existing clients       |                 |                   |
   +------------------------+-----------------+-------------------+
   | Full CMC (optional)    | /fullCMC        | Section 4.5       |
   +------------------------+-----------------+-------------------+
   | Server-side Key        | /serverKeyGen   | Section 4.6       |
   | Generation (optional)  |                 |                   |
   +------------------------+-----------------+-------------------+
   | Request CSR attributes | /CSRAttrs       | Section 4.7       |
   | (optional)             |                 |                   |
   +------------------------+-----------------+-------------------+

                                 Figure 4

   An HTTP base path common for all of an EST server's requests is
   defined in the form of an path-absolute ([RFC3986], section 3.3).
   The operation path (Figure 4 is appended to the base path to form the
   URI used with HTTP GET or POST to perform the desired EST operation.

   An example:

   With a base path of "/arbitrary/path" and an operation path of
   "/CACerts", the EST client would combine them to form an absolute
   path of "/arbitrary/path/CACerts".  Thus, to retrieve the CA's
   certificates, the EST client would use the following HTTP request:

   GET /arbitrary/path/CACerts HTTP/1.1

   Likewise, to request a new certificate enrollment in this example
   scheme, the EST client would use the following request:

   POST /arbitrary/path/simpleEnroll HTTP/1.1

   The mechanisms by which the EST server interacts with an HTTPS server



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   to handle GET and POST operations at these URIs is outside the scope
   of this document.  The use of distinct operation paths simplifies
   implementation for servers that do not perform client authentication
   when distributing "CACerts" responses.

   EST clients are to be provided with the URL of the EST server and the
   base path.  The means by which clients acquire the URL and base path
   are outside the scope of this document.  Whether the URL and base
   path are provided securely determines the authorization scheme
   required to perform operations.  (See Section 4.1.)

   An EST server MAY provide additional, non-EST services on other URIs.

   An EST server MAY use multiple base paths in order to provide service
   for multiple CAs.  Each CA would use a distinct base path, but
   operations are otherwise the same as specified for an EST server
   operating on behalf of only one CA.

3.2.3.  HTTP-Based Client Authentication

   An EST server MAY fallback to using HTTP-based client authentication
   if TLS client authentication (Section 3.3.1.2) is not possible.

   Basic and Digest authentication MUST only be performed over TLS 1.1
   [RFC4346] (or later).  As specified in CMC: Transport Protocols
   [RFC5273] the server "MUST NOT assume client support for any type of
   HTTP authentication such as cookies, Basic authentication, or Digest
   authentication".  Clients intended for deployments where password
   authentication is advantageous SHOULD support the Basic and Digest
   authentication mechanism.  Servers MAY provide configuration
   mechanisms for administrators to enable Basic [RFC2616] and Digest
   [RFC2617] authentication methods.

   Servers that support Basic and Digest authentication methods MAY
   reject requests using the HTTP defined WWW-Authenticate response-
   header ([RFC2616], Section 14.47).  At that point the client SHOULD
   repeat the request, including the appropriate Authorization Request
   Header ([RFC2617], Section 3.2.2) if the client is capable of using
   the Basic or Digest authentication.  If the client is not capable
   then the client MUST terminate the connection.

   Clients MAY set the username to the empty string ("") if they wish to
   present a "one-time password" or "PIN" that is not associated with a
   username.

   Support for HTTP-based client authentication has security
   ramifications as discussed in Section 6.  The client MUST NOT respond
   to this request unless the client has authenticated the EST server



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   (as per Section 4.1).

3.2.4.  Message types

   This document uses existing media types for the messages as specified
   by Internet X.509 Public Key Infrastructure Operational Protocols:
   FTP and HTTP [RFC2585] and The application/pkcs10 Media Type
   [RFC5967] and CMC [RFC5272].  To support distribution of multiple
   application/pkcs7-mime's for the CA certificate chain the [RFC2046]
   multipart/mixed media type is used.

   The message type is specified in the HTTP Content-Type header.  The
   use herein is consistent with [RFC5273], with clarifications made
   concerning transfer encoding.

   For reference the messages and their corresponding MIME and media
   types are:

   +-------------------+--------------------------+-------------------+
   | Message type      |Request type              | Request section   |
   |                   |Response type             | Response section  |
   |                   |Source(s) of types        |                   |
   +===================+==========================+===================+
   | CA certificate    | N/A                      | Section 4.3       |
   | request           | application/pkcs7-mime   | Section 4.3.1     |
   |                   | RFC 5751                 |                   |
   +-------------------+--------------------------+-------------------+
   | Cert enroll/renew | application/pkcs10       | Section 4.4/4.4.1 |
   |                   | application/pkcs7-mime   | Section 4.4.2     |
   |                   | RFC 5967, RFC 5751       |                   |
   +-------------------+--------------------------+-------------------+
   | Full CMC          | application/pkcs7-mime   | Section 4.5.1     |
   |                   | application/pkcs7-mime   | Section 4.5.2     |
   |                   | RFC 5751                 |                   |
   +-------------------+--------------------------+-------------------+
   | Server-side Key   | application/pkcs10       | Section 4.6.1     |
   | Generation        | multipart/mixed          | Section 4.6.2     |
   |                   | (application/pkcs7-mime &|                   |
   |                   | application/pkcs8)       |                   |
   |                   | RFC 5967, RFC 5751       |                   |
   +-------------------+--------------------------+-------------------+
   | Request CSR       | N/A                      | Section 4.7.1     |
   | attributes        | application/csrattrs     | Section 4.7.2     |
   |                   | (Specified in this RFC)  |                   |
   +-------------------+--------------------------+-------------------+


                                 Figure 5



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3.3.  TLS Layer Design

   TLS provides communications security for the layers above it.
   Specifically, the integrity and authentication services it provides
   are leveraged to supply proof-of-identity and to allow authorization
   decisions to be made.  TLS client authentication is the preferred
   method for identifying EST clients.  In lieu of that, HTTP
   authentication protected by TLS encryption is also acceptable.
   Additionally, TLS channel binding information may be optionally
   inserted into a certificate request in order to provide the EST
   server with assurance that the authenticated TLS client entity has
   possession of the private key for the certificate being requested.

   HTTP 1.1 [RFC2616] and above support persistent connections.  As
   given in Section 8.1 of that RFC persistent connections may be used
   to reduce network and processing load associated with multiple HTTP
   requests.  EST does not require persistent HTTP connections and their
   use is out of scope of this specification.

3.3.1.  TLS for transport security

   HTTPS is defined in HTTP Over TLS [RFC2818] and is a specification of
   how HTTP messages are carried over TLS.  HTTPS (e.g., HTTP over TLS)
   MUST be used.  TLS 'session resumption' SHOULD be supported.

3.3.1.1.  TLS-Based Server Authentication

   The EST client MUST authenticate the EST server by validating the TLS
   server certificate the server presented during the TLS 1.1 [RFC4346]
   (or later) exchange-defined Server Certificate message or the client
   MUST independently validate the response contents.  Validation is
   performed as given in [RFC5280] and [RFC6125].

   There are multiple methods of validation depending on the current
   state of the client:

   Method 1)  If the client has a store of trust anchors, which may be
      in the form of certificates, for authenticating TLS connections
      the client MAY validate the TLS server certificate using the
      standard HTTPS logic of checking the server's identity as
      presented in the server's Certificate message against the URI
      provisioned for the EST server (see HTTP Over TLS [RFC2818],
      Section 3.1 "Server Identity" and [RFC6125]).  This method makes
      it possible for clients with a store of trust anchors to securely
      obtain the CA certificate by leveraging the HTTPS security model.
      The EST server URI SHOULD be made available to the client in a
      secure fashion so that the client only obtains EST functions from
      a desired server.



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   Method 2)  If the client already has one or more trust anchors
      associated with this EST server, the client MUST validate the EST
      server certificate using these trust anchors.  The EST server URI
      MAY be made available to the client in an insecure fashion.  The
      EST server certificate MUST contain the id-kp-cmcRA [CMC
      RFC5272bis] extended key usage extension.

   Method 3)  If the client does not yet have a trust anchor associated
      with this EST server then the client MAY provisionally accept the
      TLS connection, but the HTTP content data MUST be accepted
      manually as described in Section 4.3.  HTTP authentication
      requests MUST NOT be responded to since the server is
      unauthenticated (only the content data is accepted manually).

   Methods 1 and 2 are essentially validation as given in [RFC5280].
   Method 1 is as described in [RFC6125], Section 6.6.1 "Match Found".
   Method 2 is described in [RFC6125] as "No Match Found, Pinned
   Certificate".  Method 3 is described in [RFC6125], Section 6.6.4 as
   "Fallback" and describes the process of "pinning" the received
   certificate.

   If one of these validation methods succeeds, the CA certificate(s)
   are stored and "pinned" for future use.  If none of these validation
   methods succeeds the client MUST reject the EST server response and
   SHOULD log and/or inform the end user.

   If Method 1 was used to authenticate the EST server then subsequent
   connections to the EST server also use Method 1.  If Method 2 was
   used to authenticate the EST server then subsequent connections to
   the EST server also use Method 2.  If Method 3 was used to manually
   authenticate the EST server then the EST client SHOULD "pin" the CA
   certificates received from a /CACerts (Section 4.3) operation and
   Method 2 is used for subsequent connections.

3.3.1.2.  TLS-Based Client Authentication

   Clients SHOULD support [RFC4346]-defined (or later) Certificate
   request (section 7.4.4).  As required by [RFC4346], the client
   certificate needs to indicate support for digital signatures.  The
   client SHOULD support this method in order to leverage
   /simpleReEnroll using client authentication by existing certificate.
   If a client does not support TLS client authentication, then it MUST
   support HTTP-based client authentication. (Section 3.2.3)

3.4.  Proof-of-Possession

   As defined in Section 2.1 of CMC [RFC5272], Proof-of-possession (POP)
   "refers to a value that can be used to prove that the private key



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   coresponding to the public key is in the possession and can be used
   by an end-entity."

   The signed enrollment request provides a "Signature"-based proof-of-
   possession.  The mechanism described in Section 3.5 strengthens this
   by optionally including "Direct"-based proof-of-possession by
   including TLS session specific information within the data covered by
   the enrollment request signature (thus linking the enrollment request
   to the authenticated end-point of the TLS connection).

3.5.  Linking Identity and POP information

   This specification provides an optional method of linking identity
   and proof-of-possession by including information specific to the
   current authenticated TLS session within the signed certification
   request.  This proves to the server that the authenticated TLS client
   has possession of the private key associated with the certification
   request and that the client was able to sign the certification
   request after the TLS session was established.  This is an
   alternative to the [RFC5272] Section 6.3-defined "Linking Identity
   and POP information" method available if full CMC messages are used.

   The client generating the request SHOULD obtain the tls-unique value
   as defined in Channel Bindings for TLS [RFC5929] from the TLS
   subsystem.  The tls-unique value is encoded as specified in Section 4
   of Base64 [RFC4648] and the resulting string is placed in the
   certification request challenge-password field.  If tls-unique
   information is not embedded within the certification request the
   challenge-password field MUST be empty.

   The tls-unique specification includes a synchronization issue as
   described in Channel Bindings for TLS [RFC5929] section 3.1.  This
   problem is avoided for EST implementations.  If the tls-unique value
   is used it MUST be from the first TLS handshake.  EST client and
   servers use their tls-unique implementation specific synchronization
   methods to obtain this first tls-unique value.

   If identity linking is used then TLS renegotiation MUST use
   "secure_renegotiation" [RFC5746] (thus maintaining the binding).
   Mandating secure renegotiation secures this method of avoiding the
   synchronization issues encountered when using the most recent tls-
   unique value (which is defined as the the value from the most recent
   TLS handshake).

   The EST server MUST verify the tls-unique information embedded within
   the certification request and MUST reject requests with invalid tls-
   unique information.  The EST server MAY be configured to accept
   requests from authenticated clients that do not include the tls-



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   unique information.

   The tls-unique value is encoded into the certification request by the
   client but back-end infrastructure elements that process the request
   after the EST server might not have access to the initial TLS
   session.  Such infrastructure elements validate the source of the
   certification request to determine if POP checks have already been
   performed.  For example if the EST client authentication results in
   an authenticated client identity of an EST server RA that is known to
   independently verify the proof-of-possession then the back-end
   infrastructure does not need to perform proof-of-possession checks a
   second time.  If the EST server forwards a request to a back-end
   process it SHOULD communicate the authentication results.  This
   communication might use the CMC "RA POP Witness Control" in a CMC
   Full PKI Request message or other mechanisms which are out-of-scope
   of this document.

   [[EDNOTE: A specific error code (TBD) is returned indicating this
   additional linkage might be useful.  This would be similar to the
   "WWW-Authenticate response-header" control message.  Alternatively
   simply rejecting the request with an informative text message would
   work in many use cases.]]


4.  Protocol Exchange Details

   Before processing a request, an EST server determines if the client
   is authorized to receive the requested services.  Likewise, the
   client must make a determination if it will accept services from the
   EST server.  Those determinations are described in the next two
   sections.  Assuming that both sides of the exchange are authorized,
   then the actual operations are as described in the sections
   following.

4.1.  Server Authorization

   The client MUST check the EST server authorization before accepting
   the server's response.  The presented certificate MUST be an end-
   entity certificate such as a CMC Registration Authority (RA)
   certificate.

   There are multiple methods for checking authorization corresponding
   to the method of server authentication used (these authorization
   methods align with the authentication methods described in
   Section 3.3.1.1):






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   Method 1)  If the client authenticated the EST server using the
      client's TLS trust anchors store, then the client MUST have
      obtained the EST server's URI in a secure fashion.  The client
      MUST check the URI "against the server's identity as presented in
      the server's Certificate message" (Section 3.1 "Server Identity"
      [RFC2818] and [RFC6125]).  The securely configured URI provides
      the authorization statement and the server's authenticated
      identity confirms it is the authorized server.

   Method 2)  If the previous check fails or is not applicable, or if
      the EST server's URI was made available to the client in an
      insecure fashion, then the EST server certificate MUST contain the
      id-kp-cmcRA [CMC RFC5272bis] extended key usage extension.  The
      client MUST further verify the server's authorization by checking
      that the [RFC5280]-defined certificate policy extension sequence
      contains the 'RA Authorization' policy OID.  The RA Authorization
      policy OID is defined as: id-cmc [[EDNOTE: TBD, perhaps 35]].  The
      RA Authorization policy information MUST NOT contain any optional
      qualifiers.

   Method 3)  If fallback logic was invoked to accept the certificate
      manually, then that authentication implies authorization of the
      EST server.

4.2.  Client Authorization

   When the EST server receives a CMC Simple PKI Request or rekey/renew
   message, the decision to issue a certificates is always a matter of
   local policy.  Thus the CA can use any data it wishes in making that
   determination.  The EST protocol exchange provides the EST server
   access to the TLS client certificate in addition to any HTTP user
   authentication credentials to help in that determination.  The
   communication channel between the TLS server implementation and the
   EST software implementation is out-of-scope of this document.

   If the client authentication is incomplete (for example if the client
   certificate is self-signed or issued by an unknown PKI or if the
   client offered an unknown username/password during HTTP
   authentication) the server MUST extract the certificate request for
   manual authorization by the administrator.

4.3.  Distribution of CA certificates

   The EST Client MAY request trust anchor information of the CA (in the
   form of certificates) by sending an HTTPS GET message to the EST
   server with an operations path of "/CACerts".  Clients SHOULD request
   an up-to-date response before stored information has expired in order
   to maintain continuity of trust.



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   The EST server SHOULD NOT require client authentication or
   authorization to reply to this request.

   The client MUST authenticate the EST server as specified in
   Section 3.3.1 and check the server's authorization as given in
   Section 4.1.  If the TLS authentication and authorization is not
   successful then the client MAY continue the TLS handshake to
   completion and proceed with the /CACerts request.  If the EST client
   continues with an unauthenticated connection the EST client MUST
   extract the CA certificate from the response (Section 4.3.1) and
   engage the end-user to authorize the CA certificate using out-of-band
   pre-configuration data such as a CA certificate "fingerprint" (e.g.,
   a SHA-1, SHA-256, SHA-512, or MD5 hash on the whole CA certificate).
   In this case it is incumbent on the end user to properly verify the
   fingerprint or to provide valid out-of-band data necessary to verify
   the fingerprint.

4.3.1.  Distribution of CA certificates response

   The EST server MUST respond to the client HTTPS GET message with CA
   trust anchor information, in the form of certificates within the CMC
   Simple PKI Response.  The response is conveyed within an HTTP
   response.

   The EST server MUST include the current CA certificate in the
   response.  The EST server MUST include any additional certificates
   the client would need to build a chain to the root certificate.  For
   example if the EST server is configured to use a subordinate CA when
   signing new client requests then the appropriate subordinate CA
   certificates to chain to the root must be included in the response.

   Additional certificates MAY be included.  If support for the CMP root
   certificate update mechanism is provided by the CA then the server
   MUST include the three "Root CA Key Update" certificates OldWithOld,
   OldWithNew, and NewWithOld.  These are defined in Section 4.4 of CMP
   [RFC4210].

   The client can always find the current self-signed CA certificate by
   examining the certificates received.  The NewWithNew certificate is
   self-signed and has the latest NotAfter date.

   The NewWithNew certificate is the certificate that is extracted and
   authorized using out-of-band information as described in Section 4.3.
   When out-of-band validation occurs each of the other three
   certificates MUST be validated using normal [RFC5280] certificate
   path validation (using the NewWithNew certificate as the trust
   anchor) before they can be used to build certificate paths during
   peer certificate validation.



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   The response format is the CMC Simple PKI Response as defined in
   [RFC5272].  The HTTP content-type of "application/pkcs7-mime" MUST be
   specified.  The CMC Simple PKI response is Base64 encoded and
   sandwiched between PEM headers:

   -----BEGIN PKCS7-----
   MIIBhDCB7gIBADBFMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEh
   Simplified example of Base64 encoding of CMC Simple PKI Response
   ED8rf3UDF6HjloiV3jBnpetx4JjZH/BlmD9HMqofVEryb1e4iZgMUvuIgwEjQwpD
   8J4OhHvLh1o=
   -----END PKCS7-----

4.4.  Simple Enrollment of Clients

   The EST client MAY request a certificate from the EST server by HTTPS
   POSTing using the operation path value of "/simpleEnroll".

   When HTTPS POSTing to the 'SimpleEnroll' location the client MUST
   include a CMC Simple PKI Request as specified in CMC Section 3.1
   (i.e., a PKCS#10 Certification Request).  Consistent with [RFC6403]
   the certification request "signature MUST be generated using the
   private key corresponding to the public key in the
   CertificationRequestInfo, for both signature and key establishment
   certification requests".  The signature provides proof-of-possession
   of the private key to the EST server.

   The HTTP content-type of "application/pkcs10" MUST be specified.  The
   format of the request is as specified in Section 6.4 of [RFC4945].

   The server MUST check client authorization as specified in
   Section 4.2.  The EST server MUST check the tls-unique value as
   described in Section 3.5 but depending on policy MAY accept a request
   without the encoded tls-unique value.  The EST server applies
   whatever authorization or policy logic it chooses in determining if
   the certificate should be issued.

   The optional client signature certificate MAY be an existing
   certificate issued by the CA the EST server is providing services for
   or it MAY be from any other PKI the EST server indicated as
   acceptable during the TLS handshake.

   The client MAY request an additional certificate even when using an
   existing certificate in the TLS client authentication.  For example
   the client can use an existing signature certificate to request a key
   encryption certificate.

   The client MUST authenticate the EST server as specified in
   Section 3.3.1.1.



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4.4.1.  Simple Re-Enrollment of Clients

   The EST client MAY request renew/rekey of its certificate from the
   EST server by HTTPS POSTing using the operation path value of
   "/simpleReEnroll'.

   The certificate request is the same format as for the "simpleEnroll"
   path extension with the same HTTP content-type.

   The server MUST check client authorization as specified in
   Section 4.2.  The EST server MUST check the tls-unique value as
   described in Section 3.5 but depending on policy MAY accept a request
   without the encoded tls-unique value.  The server applies whatever
   authorization or policy logic it chooses in determining if the
   certificate should be renewed/rekeyed.  The optional client signature
   certificate MAY be an existing certificate issued by the CA the EST
   server is providing services for or it MAY be from any other PKI the
   EST server indicated as acceptable during the TLS handshake.  When
   attempting to renew or rekey the client SHOULD use an existing
   certificate for TLS client authentication (Section 3.3.1.2).  The
   certificate being re-enrolled MAY be different than the certificate
   used for EST client authentication.

   The EST server MUST handle enrollment requests submitted to the
   "simpleReEnroll" URI as a renewal or rekey request.  (This explicit
   method of indicating a re-enroll request is an alternative to the
   /fullCMC method specified in Section 2 of [RFC5272] wherein the
   "renewal and rekey requests look the same as any certification
   request, except that the identity proof is supplied by existing
   certificates from a trusted CA").

   The request Subject/SubjectAltName field(s) MUST contain the identity
   of the certificate being re-enrolled.  The ChangeSubjectName
   attribute, as defined in [RFC6402] MAY be included in the certificate
   request.  The EST server MUST verify that that authenticated client
   is authorized to perform the inferred re-enroll operation.

   If the public key information in the certification request is the
   same as the currently issued certificate the EST server performs a
   renew operation.  If the public key information is different than the
   currently issued certificate then the EST server performs a rekey
   operation.  The specifics of these operations are out of scope of
   this profile.

   The client MUST authenticate the EST server as specified in
   Section 3.3.1.1.  The EST client is RECOMMENDED to have obtained the
   current CA certificates using Section 4.3 to ensure it can validate
   the EST server certificate.



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4.4.2.  Simple Enroll and Re-Enroll Response

   If the enrollment is successful the server response MUST have an HTTP
   200 response code with a content-type of "application/pkcs7-mime".
   The response data is a degenerate certs- only CMC Simple PKI Response
   containing only the certificate issued.  The CMC Simple PKI response
   is Base64 encoded and sandwiched between PEM headers:

   -----BEGIN PKCS7-----
   MIIBhDCB7gIBADBFMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEh
   Simplified example of Base64 encoding of CMC Simple PKI Response
   ED8rf3UDF6HjloiV3jBnpetx4JjZH/BlmD9HMqofVEryb1e4iZgMUvuIgwEjQwpD
   8J4OhHvLh1o=
   -----END PKCS7-----

   When rejecting a request the server MUST specify either an HTTP 4xx/
   401 error, or an HTTP 5xx error.  A CMC PKI Response with an HTTP
   content-type of "application/pkcs7-mime" MAY be included in the
   response data for any error response.  If the content-type is not set
   the response data MUST be a plain text human-readable error message.
   A client MAY elect not to parse a CMC error response in favor of a
   generic error message.

   If the server responds with an HTTP 202 this indicates that the
   request has been accepted for processing but that a response is not
   yet available.  The server MUST include a Retry-After header as
   defined for HTTP 503 responses and MAY include informative human-
   readable content.  The client MUST wait at least the specified
   'retry-after' time before repeating the same request.  The client
   repeats the initial enrollment request after the appropriate 'retry-
   after' interval has expired.  The client SHOULD log or inform the end
   user of this event.  The server is responsible for maintaining all
   state necessary to recognize and handle retry operations as the
   client is stateless in this regard (it simply sends the same request
   repeatedly until it receives a different response code).

   All other return codes are handled as specified in HTTP.

   If the EST client has not obtained the current CA certificates using
   Section 4.3 then it may not be able to validate the certificate
   received.

4.5.  Full CMC

   The EST client MAY request a certificate from the EST server by HTTPS
   POSTing using the operation path value of "/fullCMC".

   The client MUST authenticate the server as specified in Server



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   Authentication (Section 3.3.1.1), if method 3 is used, then the
   Publish Trust Anchors control within the HTTP content must be
   accepted manually as noted in Section 4.3.  While use of TLS is not
   optional within EST, since a full CMC message inately provides
   security, a TLS NULL cipher suite may be used while making this
   request.

   The server SHOULD authenticate the client as specified in
   Section 3.3.1.  The server MAY depend on CMC client authentication
   methods instead.

4.5.1.  Full CMC Request

   When HTTPS POSTing to the "fullCMC" location the client MUST include
   a valid CMC message.  The HTTP content-type MUST be set to
   "application/pkcs7-mime" as specified in [RFC5273].

4.5.2.  Full CMC Response

   The server responds with the client's newly issued certificate or
   provides an error response.

   If the enrollment is successful the server response MUST have an HTTP
   200 response code with a content-type of "application/pkcs7-mime" as
   specified in [RFC5273].  The response data includes either the CMC
   Simple PKI Response or the CMC Full PKI Response.

   When rejecting a request the server MAY specify either an HTTP 4xx/
   401 error or an HTTP 5xx error.  A CMC response with content-type of
   "application/pkcs7-mime" MUST be included in the response data for
   any error response.  The client MUST parse the CMC response to
   determine the current status.

   All other return codes are handled as specified in Section 4.4.2 or
   HTTP [RFC2616].

   The CMC PKI response is Base64 encoded and sandwiched between PEM
   headers:

   -----BEGIN PKCS7-----
   MIIBhDCB7gIBADBFMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEh
   Simplified example of Base64 encoding of CMC Full PKI Response
   ED8rf3UDF6HjloiV3jBnpetx4JjZH/BlmD9HMqofVEryb1e4iZgMUvuIgwEjQwpD
   8J4OhHvLh1o=
   -----END PKCS7-----






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4.6.  Server-side Key Generation

   [[EDNOTE: This section is references
   [draft-ietf-pkix-cmc-serverkeygeneration-00] which has not yet been
   published.]]

   The EST client MAY request a "private" key and associated certificate
   from the EST server by HTTPS POSTING using the operation path value
   of "/serverKeyGen".

   The client MUST authenticate the server as specified in
   Section 3.3.1.1.  The EST client is RECOMMENDED to have obtained the
   current CA certificates using Section 4.3 to ensure it can validate
   the EST server certificate.

   The EST server MUST authenticate the client as specified in
   Section 3.3.1.  The EST server applies whatever authorization or
   policy logic it chooses to determine if the "private" key and
   certificate should be distributed.  The server SHOULD use TLS-Based
   Client Authentication for authorization purposes.  The server SHOULD
   respond to repeated requests from the same client with the same
   "private" key and certificate but MAY respond with a renewed or
   rekeyed "private" key and certificate.  Clients that wish multiple
   "private" keys and certificates MUST specify a keyUsage in the
   certificate request which the server will use to intuit the type of
   key to be generated.

   Proper random number and key generation and storage is a server
   implementation responsibility.  The keypair and certificate are
   transfered over the TLS session; the EST server MUST verify that the
   current ciphersuite is acceptable for securing the key data.

4.6.1.  Server-side Key Generation Request

   The certificate request is HTTPS POSTed and is the same format as for
   the "/simpleEnroll" path extension with the same content-type.

   The public key values of the certificate request and the request
   signature MUST be ignored by the server.

4.6.2.  Server-side Key Generation Response

   If the request is successful the server response MUST have an HTTP
   200 response code with a content-type of "multipart/mixed" consisting
   of two parts.  The first part is the "private" key data and the
   second part is the certificate data.

   The first submessage is an "application/pkcs8" consisting of the



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   Base64 encoded DER-encoded PrivatekeyInfo sadwiched between the PEM
   headers as described in [RFC5958]:

   -----BEGIN PRIVATE KEY-----
   MIIBhDCB7gIBADBFMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEh
   Simplified example of Base64 encoding of DER-encoded PrivateKeyInfo
   ED8rf3UDF6HjloiV3jBnpetx4JjZH/BlmD9HMqofVEryb1e4iZgMUvuIgwEjQwpD
   8J4OhHvLh1o=
   -----END PRIVATE KEY-----

   The second submessage is an "application/pkcs7-mime" and exactly
   matches the certificate response to /simpleEnroll.  The server
   response MUST use the same SubjectPublicKeyInfo as requested or the
   request MUST be denied.

   When rejecting a request the server MUST specify either an HTTP 4xx/
   401 error, or an HTTP 5xx error.  If the content-type is not set the
   response data MUST be a plain text human-readable error message.

4.7.  CSR Attributes

   The CA MAY want to include client-provided attributes in certificates
   that it issues and some of these attributes may describe information
   that is not available to the CA.  For this reason, the EST client MAY
   request a set of attributes from the EST server to include in its
   certification request.

4.7.1.  CSR Attributes Request

   The EST Client MAY request a list of CA-desired CSR attributes from
   the CA by sending an HTTPS GET message to the EST server with an
   operations path of "/CSRAttrs".  Clients SHOULD request such a list
   if they have have no a priori knowledge of what attributes are
   desired by the CA in an enrollment request or when dictated by
   policy.

4.7.2.  CSR Attributes Response

   The server MUST reply to the client's HTTPS GET message with a (set
   of) attribute(s).  Responses to attribute request messages MUST be
   encoded as content type "application/csrattrs" and conveyed within an
   HTTP response.

   The syntax for application/csrattrs body is as follows:

   Csrattrs ::= SEQUENCE SIZE (0..MAX) OF OBJECT IDENTIFIER { }

   A robust application SHOULD output Distinguished Encoding Rules (DER)



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   ([X.690]) but MAY use Basic Encoding Rules (BER) ([X.680]).  Data
   produced by DER or BER is 8-bit.  When the transport for the
   application/csrattrs is limited to 7-bit data, a suitable transfer
   encoding MUST be applied in MIME-compatible transports.  The base64
   encoding (section 4 of [RFC4648]) SHOULD be used with application/
   csrattrs, although any 7-bit transfer encoding may work.

   Servers include zero or more object identifiers that they wish the
   client to include in their certification request.  When the server
   encodes csrattrs as an empty SEQUENCE OF it means that the server has
   no attributes it wants in client certification requests.

   For example, if a CA wishes to have a certification request contain
   the MAC address [RFC2397] of a device and the pseudonym [X.520] and
   friendly name [RFC2925] of the holder of the private analog to the
   public key in the certification request, it takes the following
   object identifiers:

   o   macAddress: 1.3.6.1.1.1.1.22

   o   pseudonym: 2.5.4.65

   o   friendlyName: 1.2.840.113549.1.9.20

   and encodes them into an ASN.1 SEQUENCE to produce:

       30 19 06 07 2b 06 01 01 01 01 16 06 03 55 04 41 06 09 2a 86 48 86
       f7 0d 01 09 14

   and then base64 encodes the resulting ASN.1 SEQUENCE to produce:

       MBkGBysGAQEBARYGA1UEQQYJKoZIhvcNAQkU

   The resulting response would look like this:

            Content-Type: application/csrattrs; name=attributes
            Content-Transfer-Encoding: base64
            Content-Disposition: attachment; filename=attributes

            MBkGBysGAQEBARYGA1UEQQYJKoZIhvcNAQkU


5.  IANA Considerations

   (This section is incomplete)

   The following aspects should be registered with IANA Considerations:




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   The RA Authorization certificate policy extension OID as discussed in
   Section 4.1 requires registration with IANA.

   [[EDNOTE: The URLs specified in Section 1 probably do not need to be
   registered with IANA.]]

   IANA SHALL update the Application Media Types registry with the
   following filled-in template from [RFC4288].

   The media subtype for Attributes in a CertificationRequest is
   application/csrattrs.

       Type name: application

       Subtype name: csrattrs

       Required parameters: None

       Optional parameters: None

       Encoding considerations: binary;

       Security Considerations:

         Clients request a list of attributes that servers wish to be in
         certification requests.  The request/response SHOULD be done in
         a TLS-protected tunnel.

       Interoperability considerations: None

       Published specification: This memo.

       Applications which use this media type:

       Enrollment over Secure Transport (EST)

       Additional information:

         Magic number(s): None

         File extension: None

         Macintosh File Type Code(s):

       Person & email address to contact for further information:

       Dan Harkins <dharkins@arubanetworks.com>




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       Restrictions on usage: None

       Author: Dan Harkins <dharkins@arubanetworks.com>

       Intended usage: COMMON

       Change controller: The IESG


6.  Security Considerations

   (This section is incomplete)

   "Badges?  We ain't got no badges.  We don't need no badges!  I don't
   have to show you any stinkin' badges!" -- The Treasure of the Sierra
   Madre.

   As described in CMC Section 6.7, "For keys that can be used as
   signature keys, signing the certification request with the private
   key serves as a POP on that key pair".  The inclusion of tls-unique
   within the certification request links the the proof-of-possession to
   the TLS proof-of-identity.

   As given in Section 3.3.1.2 clients use an existing certificate for
   TLS client authentication.  If a certificate with appropriate key
   usage is not available the client MAY generate one.  If a self-signed
   certificate with appropriate key usage is used the server SHOULD
   require HTTP-based client authentication according to server policy
   as described in Section 3.3.1.2 and Section 4.2.  The server MAY
   fallback on manual authorization by the server administrator.

   Clients authenticate EST servers by means of TLS authentication.  If
   a client does not possess a root certificate suitable for validating
   an EST server certificate, it MAY rely upon other trusted root
   certificates it has (such as those found in its HTTPS store).  The
   client then is able to retrieve additional root certificates as given
   in Section 4.3.  Alternatively, a server certificate MAY be
   authenticated manually as specified in Section 3.3.1.1 #3.

   As noted in Section 3.3.1.1 servers use an existing certificate for
   TLS server authentication.  When the server certificate is issued by
   a mutually trusted PKI hierarchy, validation proceeds as specified in
   Section 4.1.  In this situation the client has validated the server
   as being a valid responder for the URI configured but can not
   directly verify that the responder is authorized as an RA within the
   to-be-enrolled PKI hierarchy.  A client may thus be enticed to expose
   username/password or certificate enrollment requests to an
   unauthorized server (if the server presents a valid HTTPS certificate



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   for an erroneous URL that the client has been tricked into using).
   Proof-of-identity and Proof-of-possession checks by the CA prevent an
   illegitimate RA from leveraging such misconfigured clients to act as
   a man-in-the-middle during client authenticated operations but it is
   possible for such illegitimate RAs to send the client doctored
   messages or erroneous CA certificate lists.  If the illegitimate RA
   has successfully phished a username/password or PIN from the client
   it might try to use these values to enroll its own keypair with the
   real PKI hierarchy.  EST servers identified with an externally issued
   server certificate SHOULD require HTTPS-based client authentication
   (Section 3.3.1.2).  Similarly EST clients SHOULD use an existing
   client certificate to identify themselves and otherwise prevent
   "private data" (obviously including passwords but also including
   private identity information) from being exposed during the
   enrollment exchange a weak server authorization method is used.

   Section 3.2.3 allows clients to optionally authenticate using HTTP-
   based authentication in place of TLS-based authentication.  HTTP-
   based authentication MUST NOT take place unless performed over a TLS-
   protected link.

   The server-side key generation method allows keys to be transported
   over the TLS connection to the client.  The distribution of "private"
   key material is inherently risky and servers are NOT RECOMMENDED to
   support this operation by default.  Clients are NOT RECOMMENDED to
   request this service unless there is a compelling operational benefit
   such as the use of [BGPsec RPKI].

   Regarding the CSR attributes that the CA may list for inclusion in an
   enrollment request, there are no real inherent security issues with
   the content being conveyed but an adversary who is able to interpose
   herself into the conversation could exclude attributes that a server
   may want, include attributes that a server may not want, and render
   meaningless other attributes that a server may want.

   [[EDNOTE: need final reference for BGPsec RPKI]]

   Support for Basic authentication as specified in HTTP [RFC2617]
   allows the server access to the client's cleartext password.  This
   provides integration with legacy username/password databases but
   requires exposing the plaintext password to the EST server.  Use of a
   PIN or one-time-password can help mitigate concerns but EST clients
   are RECOMMENDED to use such credentials only once to obtain an
   appropriate client certificate to be used during future interactions
   with the EST server.


7.  References



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7.1.  Normative References

   [RFC2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part Two: Media Types", RFC 2046,
              November 1996.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2585]  Housley, R. and P. Hoffman, "Internet X.509 Public Key
              Infrastructure Operational Protocols: FTP and HTTP",
              RFC 2585, May 1999.

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [RFC2617]  Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
              Leach, P., Luotonen, A., and L. Stewart, "HTTP
              Authentication: Basic and Digest Access Authentication",
              RFC 2617, June 1999.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

   [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
              Request Syntax Specification Version 1.7", RFC 2986,
              November 2000.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, January 2005.

   [RFC4210]  Adams, C., Farrell, S., Kause, T., and T. Mononen,
              "Internet X.509 Public Key Infrastructure Certificate
              Management Protocol (CMP)", RFC 4210, September 2005.

   [RFC4288]  Freed, N. and J. Klensin, "Media Type Specifications and
              Registration Procedures", BCP 13, RFC 4288, December 2005.

   [RFC4346]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.1", RFC 4346, April 2006.

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, October 2006.

   [RFC4945]  Korver, B., "The Internet IP Security PKI Profile of
              IKEv1/ISAKMP, IKEv2, and PKIX", RFC 4945, August 2007.




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   [RFC5272]  Schaad, J. and M. Myers, "Certificate Management over CMS
              (CMC)", RFC 5272, June 2008.

   [RFC5273]  Schaad, J. and M. Myers, "Certificate Management over CMS
              (CMC): Transport Protocols", RFC 5273, June 2008.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, May 2008.

   [RFC5746]  Rescorla, E., Ray, M., Dispensa, S., and N. Oskov,
              "Transport Layer Security (TLS) Renegotiation Indication
              Extension", RFC 5746, February 2010.

   [RFC5929]  Altman, J., Williams, N., and L. Zhu, "Channel Bindings
              for TLS", RFC 5929, July 2010.

   [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958,
              August 2010.

   [RFC5967]  Turner, S., "The application/pkcs10 Media Type", RFC 5967,
              August 2010.

   [RFC6125]  Saint-Andre, P. and J. Hodges, "Representation and
              Verification of Domain-Based Application Service Identity
              within Internet Public Key Infrastructure Using X.509
              (PKIX) Certificates in the Context of Transport Layer
              Security (TLS)", RFC 6125, March 2011.

   [RFC6402]  Schaad, J., "Certificate Management over CMS (CMC)
              Updates", RFC 6402, November 2011.

   [X.680]    ITU-T Recommendation, "ITU-T Recommendation X.680 Abstract
              Syntax Notation One (ASN.1): Specification of basic
              notation", November 2008,
              <http://www.itu.int/rec/T-REC-X.680-200811-I/en>.

   [X.690]    ITU-T Recommendation, "ITU-T Recommendation X.690 ASN.1
              encoding rules: Specification of Basic Encoding Rules
              (BER), Canonical Encoding Rules (CER) and Distinguished
              Encoding Rules (DER)", November 2008,
              <http://www.itu.int/rec/T-REC-X.690-200811-I/en>.

7.2.  Informative References

   [IDevID]   IEEE Std, "IEEE 802.1AR Secure Device Identifier",
              December 2009, <http://standards.ieee.org/findstds/



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              standard/802.1AR-2009.html>.

   [RFC2397]  Masinter, L., "The "data" URL scheme", RFC 2397,
              August 1998.

   [RFC2925]  White, K., "Definitions of Managed Objects for Remote
              Ping, Traceroute, and Lookup Operations", RFC 2925,
              September 2000.

   [RFC6403]  Zieglar, L., Turner, S., and M. Peck, "Suite B Profile of
              Certificate Management over CMS", RFC 6403, November 2011.

   [X.520]    ITU-T Recommendation, "ITU-T Recommendation X.520 The
              Directory: Selected attribute types", November 2008,
              <http://www.itu.int/rec/T-REC-X.520-200811-I/en>.


Appendix A.  Server Discovery

   (informative)

   Clients can use DNS-SD or similar discovery algorithms to determine
   the EST server URI.  In such cases it is expected that method 2
   (Section 3.3.1.1) be used during server authentication because the
   first method is insecure if the discovery mechanism is insecure.

   If the user interaction in the third method is acceptable it is
   expected that the user would also supply the URI instead of using a
   discovery protocol.


Appendix B.  External TLS concentrator

   (informative)

   In some deployments it may be beneficial to use a TLS concentrator to
   offload the TLS processing from the server.

   The TLS server should not reject the connection based on PKIX
   validation of the client certificate.  Instead the client certificate
   is passed to the EST server layer for verification and authorization.
   This allows support of external TLS concentrators that might provide
   an independent TLS implementation.

   The TLS concentrator does validate the TLS Section 7.4.8 'Certificate
   Verify'.

   In such a deployment the TLS client authentication result must be



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   forwarded to the EST server layer.  For example a TLS concentrator
   might insert the client certificate into the HTTP header (first
   removing any existing client certificates, possibly inserted by a
   nefarious client, from the HTTP headers) before forwarding the HTTP
   connection to the EST server.

   The EST server MUST be specifically configured by the administrator
   to accept this mechanism.


Appendix C.  CGI Server implementation

   (informative)

   In some deployments it may be beneficial to use a HTTPS server that
   runs the EST server as a CGI application.

   The HTTPS server should not reject the connection based on PKIX
   validation of the client certificate.  Instead the client certificate
   is passed to the EST server layer for verification and authorization.
   This allows support of external HTTPS servers that might provide an
   independent TLS implementation.

   In such a deployment the TLS client authentication result must be
   forwarded to the EST server layer.  For example an HTTPS server might
   insert the client certificate into the environment variables before
   forwarding the HTTP data to the EST server.


Appendix D.  Operational Scenario Example Messages

   (informative)

   This section expands on the Operational Scenario Overviews by
   providing detailed examples of the messages at each TLS layer.
   Figures are informative sections of TLSv1

D.1.  Obtaining CA Certificates

   The following is an example of a valid /CACerts exchange.

   During the intial TLS handshake the client can ignore the optional
   server generated "certificate request" and can instead proceed with
   the HTTP GET request:







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   GET /CACerts HTTP/1.1
   User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS
   SL/0.9.8b zlib/1.2.3 libidn/0.6.5
   Host: 127.0.0.1:8085
   Accept: */*

   In response the server provides the current CA certificate:
   <= Recv header, 38 bytes (0x26)
   Content-Type: application/pkcs7-mime
   == Info: no chunk, no close, no size. Assume close to signal end
   <= Recv header, 2 bytes (0x2)

   <= Recv data, 1111 bytes (0x457)
   -----BEGIN PKCS7-----.MIIDEQYJKoZIhvcNAQcCoIIDAjCCAv4CAQExADALBg
   kqhkiG9w0BBwGgggLkMIIC.4DCCAcigAwIBAgIJAOjxMZcXhE5wMA0GCSqGSIb3D
   QEBBQUAMBcxFTATBgNVBAMT.DGVzdEV4YW1wbGVDQTAeFw0xMjA3MDQxODM5Mjda
   Fw0xMzA3MDQxODM5MjdaMBcx.FTATBgNVBAMTDGVzdEV4YW1wbGVDQTCCASIwDQY
   JKoZIhvcNAQEBBQADggEPADCC.AQoCggEBALQ7SjZSt6qrnBzUnBNj9z4oxYkvMA
   Vh0OIOVRkNhz/2kDGsds0ne7cw.W33kYlxPba4psdLMixCT/O8ZQMpgA+QFKtwb9
   VPE8EFUgGzxSYHQHjhJsbg0BVaN.Ya38vjKMjvosuSXUHwkvU57SInSkMr3/aNtS
   T8qFfeC6Vuf/G/GLHGuHQKAy/DSo.206MjaMNmWYRVQQVErGookRA4GBF/YE+G/C
   SlTsCQNE0KyBFz8JWIkgYY2gYkxb7.wWMvvhaU/Esp+2DG92v9Dhs2MRgrR+WPs7
   Y6CYOLD5Mr5lEdkHg27IxkSAoRrI6D.fnVVEQGCj7QrrsUgfXFVYv6cCWFfhMcCA
   wEAAaMvMC0wDAYDVR0TBAUwAwEB/zAd.BgNVHQ4EFgQUhH9KxW5TsjkgL7kg2kxJ
   yy5tD/MwDQYJKoZIhvcNAQEFBQADggEB.AD+vydZo292XFb2vXojdKD57Gv4tKVm
   hvXRdVInntzkY/0AyFCfHJ4BwndgtMh4t.rvBD8+8dL+W3jfPjcSCcUQ/JEnFuMn
   b5+kivLeqOnUshETasFPBz2Xq4C1sHDno9.CWOcsjPPw08Tn4dSrzDBSq1NdXB2z
   9NOpaVnbpb01qQGhXSOaEvcbZcDuGiW7Di3.gV++remokuPph/s6XoZffzc7ZVzf
   Job6tS4RwNz01sutPybXiRWivOz7+QeCOT87.nTGlkQH/+RImUyJ2jefjAW/GDFT
   Pzek6cZnabAtsg32n0Pv0j0/1RTNSdYGxPIVA.2f9fhMqMz+vm3w4CFNkGZnOhAD
   EA.-----END PKCS7-----.

D.2.  Previously Installed Signature Certificate

   The following is an example of a valid /simpleEnroll exchange.
   During this exchange the EST client uses an existing certificate
   issued by a trusted 3rd party PKI to obtain an initial certificate
   from the EST server.

   During the initial TLS handshake the server generated "certificate
   request" includes both the distinguished name of the CA the EST
   server provides services for ("estExampleCA") and it includes the
   distinguished name of a trusted 3rd party CA ("estEXTERNALCA"):








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   0d 00 00 3d 03 01 02 40 00 37 00 1a 30 18 31 16 ...=...@.7..0.1.
   30 14 06 03 55 04 03 13 0d 65 73 74 45 58 54 45 0...U....estEXTE
   52 4e 41 4c 43 41 00 19 30 17 31 15 30 13 06 03 RNALCA..0.1.0...
   55 04 03 13 0c 65 73 74 45 78 61 6d 70 6c 65 43 U....estExampleC
   41                                              A

   Which decodes as:

   Acceptable client certificate CA names
   /CN=estEXTERNALCA
   /CN=estExampleCA


   The EST client provides a certificate issued by "estEXTERNALCA" in
   the certificate response and the TLS handshake proceeds to
   completion.  The EST server accepts the EST client certificate for
   authentication and accepts the EST client's POSTed certificate
   request:
   POST /simpleEnroll HTTP/1.1
   User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS
   SL/0.9.8b zlib/1.2.3 libidn/0.6.5
   Host: 127.0.0.1:8085
   Accept: */*
   Content-Type: application/x-est-pkcs10
   Content-Length: 952

   => Send data, 952 bytes (0x3b8)
   -----BEGIN CERTIFICATE REQUEST-----.MIIChjCCAW4CAQAwQTElMCMGA1UE
   AxMccmVxIGJ5IGNsaWVudCBpbiBkZW1vIHN0.ZXAgNjEYMBYGA1UEBRMPUElEOld
   pZGdldCBTTjo2MIIBIjANBgkqhkiG9w0BAQEF.AAOCAQ8AMIIBCgKCAQEAwhYyI+
   aYezyx+kW0GVUbMKLf2BUd8BgGykkIJYxms6SH.Bv5S4ktcpYbEpR9iCmp96vK6a
   Ar57ArZtMmi0Y6eLX4c+njJnYhUeTivnfyfMM5d.hNVwyzKbJagm5f+RLTMfp0y0
   ykqrfZ1hFhcNrRzF6mJeaORTHBehMdu8RXcbmy5R.s+vjnUC4Fe3/oLHtXePyYv1
   qqlkk0XDrw/+lx0y4Px5tiyb84iPnQOXjG2tuStM+.iEvfpNAnwU0+3GDjl3sjx0
   +gTKvblp6Diw9NSaqIAKupcgWsA0JlyYkgPiJnXFKL.vy6rXoOyx3wAbGKLrKCxT
   l+RH3oNXf3UCH70aD758QIDAQABoAAwDQYJKoZIhvcN.AQEFBQADggEBADwpafWU
   BsOJ2g2oyHQ7Ksw6MwvimjhB7GhjweCcceTSLInUMk10.4E0TfNqaWcoQengMVZr
   IcbOb+sa69BWNB/WYIULfEtJIV23/g3n/y3JltMNw/q+R.200t0bNAViijHQHmlF
   6dt93tkRrTzXnhV70Ijnff08G7P9HfnXQH4Eiv3zOB6Pak.JoL7QlWQ+w5vHpPo6
   WGH5n2iE+Ql76F0HykGeqaR402+ae0WlGLHEvcN9wiFQVKh.KUHteU10SEPijlqf
   QW+hciLleX2CwuZY5MqKb4qqyDTs4HSQCBCl8jR2cXsGDuN4.PcMPp+9A1/UPuGD
   jhwPt/K3y6aV8zUEh8Ws=.-----END CERTIFICATE REQUEST-----.

   The EST server uses the trusted 3rd party CA issued certificate to
   perform additional authorization and issues a certificate to the
   client:





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   <= Recv header, 38 bytes (0x26)
   Content-Type: application/pkcs7-mime
   == Info: no chunk, no close, no size. Assume close to signal end
   <= Recv header, 2 bytes (0x2)

   <= Recv data, 1200 bytes (0x4b0)
   -----BEGIN PKCS7-----.MIIDUQYJKoZIhvcNAQcCoIIDQjCCAz4CAQExADALBg
   kqhkiG9w0BBwGgggMkMIID.IDCCAgigAwIBAgIBBjANBgkqhkiG9w0BAQUFADAXM
   RUwEwYDVQQDEwxlc3RFeGFt.cGxlQ0EwHhcNMTIwNzA0MTgzOTM3WhcNMTMwNzA0
   MTgzOTM3WjBBMSUwIwYDVQQD.ExxyZXEgYnkgY2xpZW50IGluIGRlbW8gc3RlcCA
   2MRgwFgYDVQQFEw9QSUQ6V2lk.Z2V0IFNOOjYwggEiMA0GCSqGSIb3DQEBAQUAA4
   IBDwAwggEKAoIBAQDCFjIj5ph7.PLH6RbQZVRswot/YFR3wGAbKSQgljGazpIcG/
   lLiS1ylhsSlH2IKan3q8rpoCvns.Ctm0yaLRjp4tfhz6eMmdiFR5OK+d/J8wzl2E
   1XDLMpslqCbl/5EtMx+nTLTKSqt9.nWEWFw2tHMXqYl5o5FMcF6Ex27xFdxubLlG
   z6+OdQLgV7f+gse1d4/Ji/WqqWSTR.cOvD/6XHTLg/Hm2LJvziI+dA5eMba25K0z
   6IS9+k0CfBTT7cYOOXeyPHT6BMq9uW.noOLD01JqogAq6lyBawDQmXJiSA+ImdcU
   ou/Lqteg7LHfABsYousoLFOX5Efeg1d./dQIfvRoPvnxAgMBAAGjTTBLMAkGA1Ud
   EwQCMAAwHQYDVR0OBBYEFJv4oLLeNxNK.OMmQDDujyNR+zaVPMB8GA1UdIwQYMBa
   AFIR/SsVuU7I5IC+5INpMScsubQ/zMA0G.CSqGSIb3DQEBBQUAA4IBAQCMdomfdR
   9vi4VUYdF+eym7F8qVUG/1jtjfaxmrzKeZ.7LQ1F758RtwG9CDu2GPHNPjjeM+DJ
   RQZN999eLs3Qd/DIJCNimaqdDqmkeBFC5hq.LZOxbKhSmhlR7YKjIZuyI299rOaI
   W54ULyz8k0zw6R1/0lMJTsDFGJM+9yDeaARE.n3vtKnUDGHsVU3fYpDENaqUunoU
   MZfuEdejfHhU7lVbJI1oSJbnRwBFkPr/RQ3/5.FymcrBD9RpAM5MsQIn0BONil/o
   JM+LjOJqyZLbBxz6P3w/OiJGYJNfFT8YudLfjZ.LDX8A8FFcReapNELC4QxE4OrA
   hN3sQUT2O7ndIsit4kJoQAxAA==.-----END PKCS7-----.

D.3.  Username/Password Distributed Out-of-Band

   The following is an example of a valid /simpleEnroll exchange.
   During this exchange the EST client uses an out-of-band distributed
   username/password to authenticate itself to the EST server.

   During the intial TLS handshake the client can ignore the optional
   server generated "certificate request" and can instead proceed with
   the HTTP POST request:
















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   POST /simpleEnroll HTTP/1.1
   User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS
   SL/0.9.8b zlib/1.2.3 libidn/0.6.5
   Host: 127.0.0.1:8085
   Accept: */*
   Content-Type: application/x-est-pkcs10
   Content-Length: 952

   => Send data, 952 bytes (0x3b8)
   -----BEGIN CERTIFICATE REQUEST-----.MIIChjCCAW4CAQAwQTElMCMGA1UE
   AxMccmVxIGJ5IGNsaWVudCBpbiBkZW1vIHN0.ZXAgMjEYMBYGA1UEBRMPUElEOld
   pZGdldCBTTjoyMIIBIjANBgkqhkiG9w0BAQEF.AAOCAQ8AMIIBCgKCAQEAz9lXz9
   MowulOx0W5v1k7GKlsNy7mAgmkz/wZDImBDXez.QZCb8lrO8iTD3tI0NH2xpkY3b
   uqFjdtQTzCmANLyNWtR1sC5GjN/EM1JSCrO/zZM.ig835RXJTP878N/jNW7EzSxb
   /zK5OzKJoRbZ4HgZm4NDapMfMcB4jqBdPxoPAqeR.+KTkv1+9m1vvsdKIs5Hm4Sp
   O2WolHPw5BCXdu5zleb6ACih7Zpd2cpHFz6ZHC0G1.Of+F//0BzkFSqWsmUomyJy
   WCfLCuX9grs1CNlLxw0gcMprdTxLxjc18z03ZmBCq0.qq5/mUK/tv9R2k8+WuP3a
   kzTUIkeHtcp6FVFl3D+TwIDAQABoAAwDQYJKoZIhvcN.AQEFBQADggEBAJH7Etuy
   B/oQgQeals08mD2U31FfQ/uYqjNxzZpZJSzVLGMASv9a.pNzaWdfqPdIs+ZZ+gAQ
   QkVcXjdbqY3pAf/EeWk+KnuAUjOIPKu3ZBPVbWbXu/Ie7.F1ekQ7TLkFNkHSxHRu
   2/bPIByBLRVfWNVXd3wPq+QxqMqgIjBGaTJM5kuHndYFGj.Xdf4rlGRPyOOwG/Xf
   QrKBB3tzpbJCy+cwOUAJFPOTO+86RUjf9Wh+yoM182vlg8O.FyEaaA/PMpl3aEcT
   BlRZmPx4e7FLwGIhbgE7/6K0nF99xdGd7JYPHasbcWszxD0Z.oPYm+44g0gOnhlj
   OWpRiKXcnngSSutRILaw=.-----END CERTIFICATE REQUEST-----.
   == Info: upload completely sent off: 952 out of 952 bytes
   == Info: HTTP 1.1 or later with persistent connection, pipelining
      supported

   The EST server accepts this request but since a client certificate
   was not provided for authentication/authorization the EST server
   responds with the WWW-authenticate header:
   <= Recv header, 27 bytes (0x1b)
   HTTP/1.1 401 Unauthorized
   <= Recv header, 75 bytes (0x4b)
   WWW-Authenticate: Digest qop="auth", realm="estrealm", nonce="13
   41427174"

   The EST client repeats the request, this time including the requested
   Authorization header:












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   == Info: SSL connection using AES256-SHA
   == Info: Server certificate:
   == Info:  subject: CN=127.0.0.1
   == Info:  start date: 2012-07-04 18:39:27 GMT
   == Info:  expire date: 2013-07-04 18:39:27 GMT
   == Info:  common name: 127.0.0.1 (matched)
   == Info:  issuer: CN=estExampleCA
   == Info:  SSL certificate verify ok.
   == Info: Server auth using Digest with user 'estuser'
   => Send header, 416 bytes (0x1a0)
   POST /simpleEnroll HTTP/1.1
   Authorization: Digest username="estuser", realm="estrealm", nonc
   e="1341427174", uri="/simpleEnroll", cnonce="ODc0OTk2", nc=00000
   001, qop="auth", response="48a2b671ccb6596adfef039e134b7d5d"
   User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS
   SL/0.9.8b zlib/1.2.3 libidn/0.6.5
   Host: 127.0.0.1:8085
   Accept: */*
   Content-Type: application/x-est-pkcs10
   Content-Length: 952

   => Send data, 952 bytes (0x3b8)
   -----BEGIN CERTIFICATE REQUEST-----.MIIChjCCAW4CAQAwQTElMCMGA1UE
   AxMccmVxIGJ5IGNsaWVudCBpbiBkZW1vIHN0.ZXAgMjEYMBYGA1UEBRMPUElEOld
   pZGdldCBTTjoyMIIBIjANBgkqhkiG9w0BAQEF.AAOCAQ8AMIIBCgKCAQEAz9lXz9
   MowulOx0W5v1k7GKlsNy7mAgmkz/wZDImBDXez.QZCb8lrO8iTD3tI0NH2xpkY3b
   uqFjdtQTzCmANLyNWtR1sC5GjN/EM1JSCrO/zZM.ig835RXJTP878N/jNW7EzSxb
   /zK5OzKJoRbZ4HgZm4NDapMfMcB4jqBdPxoPAqeR.+KTkv1+9m1vvsdKIs5Hm4Sp
   O2WolHPw5BCXdu5zleb6ACih7Zpd2cpHFz6ZHC0G1.Of+F//0BzkFSqWsmUomyJy
   WCfLCuX9grs1CNlLxw0gcMprdTxLxjc18z03ZmBCq0.qq5/mUK/tv9R2k8+WuP3a
   kzTUIkeHtcp6FVFl3D+TwIDAQABoAAwDQYJKoZIhvcN.AQEFBQADggEBAJH7Etuy
   B/oQgQeals08mD2U31FfQ/uYqjNxzZpZJSzVLGMASv9a.pNzaWdfqPdIs+ZZ+gAQ
   QkVcXjdbqY3pAf/EeWk+KnuAUjOIPKu3ZBPVbWbXu/Ie7.F1ekQ7TLkFNkHSxHRu
   2/bPIByBLRVfWNVXd3wPq+QxqMqgIjBGaTJM5kuHndYFGj.Xdf4rlGRPyOOwG/Xf
   QrKBB3tzpbJCy+cwOUAJFPOTO+86RUjf9Wh+yoM182vlg8O.FyEaaA/PMpl3aEcT
   BlRZmPx4e7FLwGIhbgE7/6K0nF99xdGd7JYPHasbcWszxD0Z.oPYm+44g0gOnhlj
   OWpRiKXcnngSSutRILaw=.-----END CERTIFICATE REQUEST-----.

   The ESTserver uses the username/password to perform authentication/
   authorization and responds with the issued certificate:











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   <= Recv header, 38 bytes (0x26)
   0000: Content-Type: application/pkcs7-mime
   == Info: no chunk, no close, no size. Assume close to signal end
   <= Recv header, 2 bytes (0x2)

   <= Recv data, 1200 bytes (0x4b0)
   -----BEGIN PKCS7-----.MIIDUQYJKoZIhvcNAQcCoIIDQjCCAz4CAQExADALBg
   kqhkiG9w0BBwGgggMkMIID.IDCCAgigAwIBAgIBAjANBgkqhkiG9w0BAQUFADAXM
   RUwEwYDVQQDEwxlc3RFeGFt.cGxlQ0EwHhcNMTIwNzA0MTgzOTM0WhcNMTMwNzA0
   MTgzOTM0WjBBMSUwIwYDVQQD.ExxyZXEgYnkgY2xpZW50IGluIGRlbW8gc3RlcCA
   yMRgwFgYDVQQFEw9QSUQ6V2lk.Z2V0IFNOOjIwggEiMA0GCSqGSIb3DQEBAQUAA4
   IBDwAwggEKAoIBAQDP2VfP0yjC.6U7HRbm/WTsYqWw3LuYCCaTP/BkMiYENd7NBk
   JvyWs7yJMPe0jQ0fbGmRjdu6oWN.21BPMKYA0vI1a1HWwLkaM38QzUlIKs7/NkyK
   DzflFclM/zvw3+M1bsTNLFv/Mrk7.MomhFtngeBmbg0Nqkx8xwHiOoF0/Gg8Cp5H
   4pOS/X72bW++x0oizkebhKk7ZaiUc./DkEJd27nOV5voAKKHtml3ZykcXPpkcLQb
   U5/4X//QHOQVKpayZSibInJYJ8sK5f.2CuzUI2UvHDSBwymt1PEvGNzXzPTdmYEK
   rSqrn+ZQr+2/1HaTz5a4/dqTNNQiR4e.1ynoVUWXcP5PAgMBAAGjTTBLMAkGA1Ud
   EwQCMAAwHQYDVR0OBBYEFChDQpKEfG9c.e4JaMf8438tb2XOIMB8GA1UdIwQYMBa
   AFIR/SsVuU7I5IC+5INpMScsubQ/zMA0G.CSqGSIb3DQEBBQUAA4IBAQAn42mIVG
   piaY4yqFD0F8KyUhKsdNnyKeeISQxP//lp.quIieJzdWSc7bhWZNldSzNswCod8B
   4eJToQejLSNb8JBDC849z0tcuyHgN6N/p8z.IwI+hAlfXS9q02OECyFes4Jmzc7r
   erE5jtOdGsEDBIscw/A+Kv86wv6BKbagMslQ.51AJyPsL6iBhm7LPFrErJgH2kWN
   jDKFH9CcVFjXvgriMrLPFeqQWOpj/2XF+4m+c.f9QP5tSjieHJR1hnYk2tlodfE7
   iV4pJ07Mmf3yBf753VSUVybqWiMCd0Lm7oghSX.E2GAxrsU1N+N1odn+gJ2wmxTu
   AC2aHt9VPRViov4RRTvoQAxAA==.-----END PKCS7-----.

D.4.  Re-Enrollment

   The following is an example of a valid /simpleReEnroll exchange.
   During this exchange the EST client authenticates itself using an
   existing certificate issued by the CA the EST server provides
   services for.

   Initially this exchange is identical to enrollment using an
   externally issued certificate for client authentication since the
   server is not yet aware of the client's intention.  As in that
   example the EST server the server generated "certificate request"
   includes both the distinguished name of the CA the EST server
   provides services for ("estExampleCA") and it includes the
   distinguished name of a trusted 3rd party CA ("estEXTERNALCA").











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   0d 00 00 3d 03 01 02 40 00 37 00 1a 30 18 31 16 ...=...@.7..0.1.
   30 14 06 03 55 04 03 13 0d 65 73 74 45 58 54 45 0...U....estEXTE
   52 4e 41 4c 43 41 00 19 30 17 31 15 30 13 06 03 RNALCA..0.1.0...
   55 04 03 13 0c 65 73 74 45 78 61 6d 70 6c 65 43 U....estExampleC
   41                                              A

   In text format this is:

   Acceptable client certificate CA names
   /CN=estEXTERNALCA
   /CN=estExampleCA


   The EST client provides a certificate issued by "estExampleCA" in the
   certificate response and the TLS handshake proceeds to completion.
   The EST server accepts the EST client certificate for authentication
   and accepts the EST client's POSTed certificate request.

   The rest of the protocol traffic is effectively identical to a normal
   enrollment.

D.5.  Server Key Generation

   The following is an example of a valid /serverKeyGen exchange.
   During this exchange the EST client authenticates itself using an
   existing certificate issued by the CA the EST server provides
   services for.

   The initial TLS handshake is identical to the enrollment example
   handshake.  The HTTP POSTed message is:





















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   POST /serverKeyGen HTTP/1.1
   User-Agent: curl/7.24.0 (i686-pc-linux-gnu) libcurl/7.24.0 OpenS
   SL/0.9.8b zlib/1.2.3 libidn/0.6.5
   Host: 127.0.0.1:8085
   Accept: */*
   Content-Type: application/x-est-pkcs10
   Content-Length: 968

   => Send data, 968 bytes (0x3c8)
   -----BEGIN CERTIFICATE REQUEST-----.MIICkzCCAXsCAQAwTjEyMDAGA1UE
   AxMpc2VydmVyS2V5R2VuIHJlcSBieSBjbGll.bnQgaW4gZGVtbyBzdGVwIDUxGDA
   WBgNVBAUTD1BJRDpXaWRnZXQgU046NTCCASIw.DQYJKoZIhvcNAQEBBQADggEPAD
   CCAQoCggEBAMnlUlq0ag/fDAVhLgrXEAD6WtZw.Y2rVGev5saWirer2n0OzghB59
   uJByxPo0DYBYqZRuoRF0FTL1ZZTMaZxivge0ecA.ZcoR46jwSBoceMT1jkwFyAER
   t9Q2EwdnJLIPo/Ib2PLJNb4Jo8NNKmxtg55BgIVi.vkIB+rMtLeYRUVL0RUaBAqX
   FmtXRDceVFIEY24iUQw6vESGJKpArht592aT8lyaP.24bZovuG19dd5xtTX3j37K
   x49SlkUvLSpD6ZavIFAZn7Yv19LBKHvRIemybUo294.QeLb/VYP1O+EAthV/igiX
   1DHqlUZCZp5SdyUXUwZPatFboNwEVR0R3MJwVECAwEA.AaAAMA0GCSqGSIb3DQEB
   BQUAA4IBAQAqhHezK5/tvbXleHO/aTBVYO9l414NM+WA.wJcnS2UaJYScPBqlYK/
   gij+dqAtFE+5ukAj56t7HnooI4EFo9r8jqCHewx7iLZYh.JDxo4hWOsAvHV+Iziy
   jkhJNdHBIqGM7Gd5f/2VJLEPQPmwNOL5P+2O4eQC/QeEYc.bAmfhOS8b/ZH09/9T
   PeaeQpjspjOui/100OuLE8KvU3FM0sXMYt1Va0A0jxzl+5k.EiEJo+ltXsQwdP0H
   csoTNBN+j3K18omJQS0e91X8v0xkMWYhUtonXD0YZ6SO/B9c.AE6GTADHA/xpSvA
   cqlWa+FHxjwEMXdmViHvMUywo31fDZ/TUvCPX.-----END CERTIFICATE REQUE
   ST-----.

   After processing the request the EST server response is:
   <= Recv header, 17 bytes (0x11)
   HTTP/1.1 200 OK
   <= Recv header, 16 bytes (0x10)
   Status: 200 OK
   <= Recv header, 67 bytes (0x43)
   Content-Type: multipart/mixed ; boundary=estServerExampleBoundar
   y
   == Info: no chunk, no close, no size. Assume close to signal end
   <= Recv header, 2 bytes (0x2)

   <= Recv data, 3234 bytes (0xca2)
   This is the preamble. It is to be ignored, though it.is a handy
   place for estServer to include an explanatory note.including con
   tact or support information..--estServerExampleBoundary.Content-
   Type=application/pkcs8..-----BEGIN PRIVATE KEY-----.MIIEvQIBADAN
   BgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC0781l7tri0yii.Mb9ZZYch8ze
   izXrjMPF/Rxoz2C9IU2THCrhPGXGQMne/zivce0m8/BMkkUc+DsSM.tzxn4l+9tI
   sVDkAe4FyzN0hLd/zawgj6kUoCi3mxZnb2rWaRYAmM5w41ImDV3blv.aMUKDSJhV
   bQ+z/G1W1TRx3iWi5CMHYb+1pJXPTJz/GuWr/b/+Efqwz2ZlwGcj4Dx.Igbx9vG0
   mftIIxM4TUX28KBbaLgJbalsiuOx3C2bEyaSPerdzqgvXFHGGAhg1FU8.DQiQEki
   nn66GPMtm1SNgitxFxWouFqpsax5MWn/i52TfEaF2PNThOuzKtilweJhk.g0gMIQ



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   TXAgMBAAECggEANlrz8XNX/lxBELixK0H83o4aYKYqDKZfZkUN8hU33xpu.Y/0sc
   VbLbu46WzysoIfJFyUC+zFJnbMCCOPjGbI/4NWkEqc9TAlKz+wDo+hf5bf0.ypFr
   EmikHk8R3fkpnvKi69ldw0iYnqcFVhq7VtGrSmJcy6Hckwbk7EBoUZGL0wtp.xlO
   6XlhksAvn8+75qoWzsNhi7S/L0IVCVLbUaV3hodTHlH5M4daFbqyRWD7UiPKt.Q3
   hdw1rpyVZg8ZbBFp0Ej4f9GdRaq88SIKMKCDu3t9ibn/v1kEte+PxhuwyW+d0o.h
   kKSEW0yLKCzQm5tujsPq0UVzPBkLJACUnFAi+a4AQKBgQDu6VLH2eYoTjPPTyAv.
   vOJnNWP7oMzyJ4/eFqdE9m+2Ajm/0qaMY95ftZ+GpEKggvC6Z5DFevEmgH4Sg2+G
   .gFd93diyRPScVbNE8SmpXxLPU2UoykVmICuQZzLDNE18B3buxAm2GJ219NEnZOe
   c.jPMOV/IcG1aLzTqQssL3zo/0gQKBgQDB4Olpg3EBggtJ/+dlkLHUw8c7Pe3UyL
   kS.VxVsyQwioYt8xMeCWuPvPNFcOjcW53KN/YSpCVjpttKGsPtLibMlKYKgasEqg
   cvl.Vb5OFtA/jNAP3mdAgCzBn6IF1NhVQe2dclo5puZ0gO38HDWq7EtqSi9Q0JSM
   g3YC.QNcOORptVwKBgQCHrCafaYWDhA11/+g2U9x6Yd56ifF43rCbnV+2EQCVaqQ
   i49xC.w4AH+Bs0mdlgT5unL6MOEmgZxkRR/SP7TKzixHYHnpMOqLhaQV24Wk5TQH
   ek92D7.wu8aXRB9vBj4g0CuDNO6/jWpm/KenXXN+Fka3ySVg4zdbVmBzJJdqYckg
   QKBgFXS.zSBzGgwz1/F7AaDZK49m1wPnhyeBb0OqHwbX/LI71rZ1mWef+nSF9Juh
   /Y77B5/J.UPdO9vgGgS00nRk0LIRP2s5OU5IQgQTVLvf8a1UmbVgI+KX511Yi5yM
   ztEwRcjEX.VM9ejXeXN0I57pvqG/xCOK3Kl2eYLh4TO9/E8WjjAoGAA1mqUV4Hnf
   4yvF1rydMp.fpvoWekiiRE33iEbYZNATYhsl7uxwn760pqVifkq2DSrZeYm4+lw9
   jwWMtUoPzpg.CJYMoGl846nhiZrbbJ5b5twoLV6GRmkk/CfOxPXNzCtSoQA86HHq
   7rRdhXSau/bY.EXc91tnhLjFzZxdBgrd+f4k=.-----END PRIVATE KEY-----.
   --estServerExampleBoundary.Content-Type: application/pkcs7-mime.
   .-----BEGIN PKCS7-----.MIIDPAYJKoZIhvcNAQcCoIIDLTCCAykCAQExADALB
   gkqhkiG9w0BBwGgggMPMIID.CzCCAfOgAwIBAgIBBTANBgkqhkiG9w0BAQUFADAX
   MRUwEwYDVQQDEwxlc3RFeGFt.cGxlQ0EwHhcNMTIwNzA0MTgzOTM2WhcNMTMwNzA
   0MTgzOTM2WjAsMSowKAYDVQQD.EyFzZXJ2ZXJzaWRlIGtleSBnZW5lcmF0ZWQgcm
   VzcG9uc2UwggEiMA0GCSqGSIb3.DQEBAQUAA4IBDwAwggEKAoIBAQC0781l7tri0
   yiiMb9ZZYch8zeizXrjMPF/Rxoz.2C9IU2THCrhPGXGQMne/zivce0m8/BMkkUc+
   DsSMtzxn4l+9tIsVDkAe4FyzN0hL.d/zawgj6kUoCi3mxZnb2rWaRYAmM5w41ImD
   V3blvaMUKDSJhVbQ+z/G1W1TRx3iW.i5CMHYb+1pJXPTJz/GuWr/b/+Efqwz2Zlw
   Gcj4DxIgbx9vG0mftIIxM4TUX28KBb.aLgJbalsiuOx3C2bEyaSPerdzqgvXFHGG
   Ahg1FU8DQiQEkinn66GPMtm1SNgitxF.xWouFqpsax5MWn/i52TfEaF2PNThOuzK
   tilweJhkg0gMIQTXAgMBAAGjTTBLMAkG.A1UdEwQCMAAwHQYDVR0OBBYEFLylcQN
   0D5xTfRdayv+0GDULR2+EMB8GA1UdIwQY.MBaAFIR/SsVuU7I5IC+5INpMScsubQ
   /zMA0GCSqGSIb3DQEBBQUAA4IBAQButIeM.DB9PkwlGGe7zqvUWVD8y99zowwV6A
   rAOXWX+JO0bihgMtZaUfvPCX/LhZVEKDAki.W5orjAEvIu10b6l38ZzX2oyJgkYy
   Mmbb14lzTsRyjiqFw9j1PXxwgZvhwcaCF4b7.eDUUBQIeZg3AnkQrEwnHR5oVIN5
   8qo0P7PSKC3Vl3H6DlQh3y7w87nN12923/wk0.v/bS3lv7lDX3HdmbQD1r2KPtBs
   JGF4jMdstT7FTx32ZFKObycbK7WJ4LHytNJDci.4iXf+B0S3D6Zbf1cXj80/W+jC
   GvU0+4SV3cgEXFE5VQvXd8x40W4h0dTSkQCDPOS.nPj4Dl/PsLqX3lDboQAxAA==
   .-----END PKCS7-----.--estServerExampleBoundary--.This is the ep
   ilogue. It is also to be ignored..

   In text format this is:

   HTTP/1.1 200 OK
   Status: 200 OK
   Content-Type: multipart/mixed ; boundary=estServerExampleBoundary




Pritikin, et al.        Expires January 11, 2013               [Page 44]

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   This is the preamble. It is to be ignored, though it
   is a handy place for estServer to include an explanatory note
   including contact or support information.
   --estServerExampleBoundary
   Content-Type=application/pkcs8

   -----BEGIN PRIVATE KEY-----
   MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC0781l7tri0yii
   Mb9ZZYch8zeizXrjMPF/Rxoz2C9IU2THCrhPGXGQMne/zivce0m8/BMkkUc+DsSM
   tzxn4l+9tIsVDkAe4FyzN0hLd/zawgj6kUoCi3mxZnb2rWaRYAmM5w41ImDV3blv
   aMUKDSJhVbQ+z/G1W1TRx3iWi5CMHYb+1pJXPTJz/GuWr/b/+Efqwz2ZlwGcj4Dx
   Igbx9vG0mftIIxM4TUX28KBbaLgJbalsiuOx3C2bEyaSPerdzqgvXFHGGAhg1FU8
   DQiQEkinn66GPMtm1SNgitxFxWouFqpsax5MWn/i52TfEaF2PNThOuzKtilweJhk
   g0gMIQTXAgMBAAECggEANlrz8XNX/lxBELixK0H83o4aYKYqDKZfZkUN8hU33xpu
   Y/0scVbLbu46WzysoIfJFyUC+zFJnbMCCOPjGbI/4NWkEqc9TAlKz+wDo+hf5bf0
   ypFrEmikHk8R3fkpnvKi69ldw0iYnqcFVhq7VtGrSmJcy6Hckwbk7EBoUZGL0wtp
   xlO6XlhksAvn8+75qoWzsNhi7S/L0IVCVLbUaV3hodTHlH5M4daFbqyRWD7UiPKt
   Q3hdw1rpyVZg8ZbBFp0Ej4f9GdRaq88SIKMKCDu3t9ibn/v1kEte+PxhuwyW+d0o
   hkKSEW0yLKCzQm5tujsPq0UVzPBkLJACUnFAi+a4AQKBgQDu6VLH2eYoTjPPTyAv
   vOJnNWP7oMzyJ4/eFqdE9m+2Ajm/0qaMY95ftZ+GpEKggvC6Z5DFevEmgH4Sg2+G
   gFd93diyRPScVbNE8SmpXxLPU2UoykVmICuQZzLDNE18B3buxAm2GJ219NEnZOec
   jPMOV/IcG1aLzTqQssL3zo/0gQKBgQDB4Olpg3EBggtJ/+dlkLHUw8c7Pe3UyLkS
   VxVsyQwioYt8xMeCWuPvPNFcOjcW53KN/YSpCVjpttKGsPtLibMlKYKgasEqgcvl
   Vb5OFtA/jNAP3mdAgCzBn6IF1NhVQe2dclo5puZ0gO38HDWq7EtqSi9Q0JSMg3YC
   QNcOORptVwKBgQCHrCafaYWDhA11/+g2U9x6Yd56ifF43rCbnV+2EQCVaqQi49xC
   w4AH+Bs0mdlgT5unL6MOEmgZxkRR/SP7TKzixHYHnpMOqLhaQV24Wk5TQHek92D7
   wu8aXRB9vBj4g0CuDNO6/jWpm/KenXXN+Fka3ySVg4zdbVmBzJJdqYckgQKBgFXS
   zSBzGgwz1/F7AaDZK49m1wPnhyeBb0OqHwbX/LI71rZ1mWef+nSF9Juh/Y77B5/J
   UPdO9vgGgS00nRk0LIRP2s5OU5IQgQTVLvf8a1UmbVgI+KX511Yi5yMztEwRcjEX
   VM9ejXeXN0I57pvqG/xCOK3Kl2eYLh4TO9/E8WjjAoGAA1mqUV4Hnf4yvF1rydMp
   fpvoWekiiRE33iEbYZNATYhsl7uxwn760pqVifkq2DSrZeYm4+lw9jwWMtUoPzpg
   CJYMoGl846nhiZrbbJ5b5twoLV6GRmkk/CfOxPXNzCtSoQA86HHq7rRdhXSau/bY
   EXc91tnhLjFzZxdBgrd+f4k=
   -----END PRIVATE KEY-----
   --estServerExampleBoundary
   Content-Type: application/pkcs7-mime

   -----BEGIN PKCS7-----
   MIIDPAYJKoZIhvcNAQcCoIIDLTCCAykCAQExADALBgkqhkiG9w0BBwGgggMPMIID
   CzCCAfOgAwIBAgIBBTANBgkqhkiG9w0BAQUFADAXMRUwEwYDVQQDEwxlc3RFeGFt
   cGxlQ0EwHhcNMTIwNzA0MTgzOTM2WhcNMTMwNzA0MTgzOTM2WjAsMSowKAYDVQQD
   EyFzZXJ2ZXJzaWRlIGtleSBnZW5lcmF0ZWQgcmVzcG9uc2UwggEiMA0GCSqGSIb3
   DQEBAQUAA4IBDwAwggEKAoIBAQC0781l7tri0yiiMb9ZZYch8zeizXrjMPF/Rxoz
   2C9IU2THCrhPGXGQMne/zivce0m8/BMkkUc+DsSMtzxn4l+9tIsVDkAe4FyzN0hL
   d/zawgj6kUoCi3mxZnb2rWaRYAmM5w41ImDV3blvaMUKDSJhVbQ+z/G1W1TRx3iW
   i5CMHYb+1pJXPTJz/GuWr/b/+Efqwz2ZlwGcj4DxIgbx9vG0mftIIxM4TUX28KBb
   aLgJbalsiuOx3C2bEyaSPerdzqgvXFHGGAhg1FU8DQiQEkinn66GPMtm1SNgitxF
   xWouFqpsax5MWn/i52TfEaF2PNThOuzKtilweJhkg0gMIQTXAgMBAAGjTTBLMAkG



Pritikin, et al.        Expires January 11, 2013               [Page 45]

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   A1UdEwQCMAAwHQYDVR0OBBYEFLylcQN0D5xTfRdayv+0GDULR2+EMB8GA1UdIwQY
   MBaAFIR/SsVuU7I5IC+5INpMScsubQ/zMA0GCSqGSIb3DQEBBQUAA4IBAQButIeM
   DB9PkwlGGe7zqvUWVD8y99zowwV6ArAOXWX+JO0bihgMtZaUfvPCX/LhZVEKDAki
   W5orjAEvIu10b6l38ZzX2oyJgkYyMmbb14lzTsRyjiqFw9j1PXxwgZvhwcaCF4b7
   eDUUBQIeZg3AnkQrEwnHR5oVIN58qo0P7PSKC3Vl3H6DlQh3y7w87nN12923/wk0
   v/bS3lv7lDX3HdmbQD1r2KPtBsJGF4jMdstT7FTx32ZFKObycbK7WJ4LHytNJDci
   4iXf+B0S3D6Zbf1cXj80/W+jCGvU0+4SV3cgEXFE5VQvXd8x40W4h0dTSkQCDPOS
   nPj4Dl/PsLqX3lDboQAxAA==
   -----END PKCS7-----
   --estServerExampleBoundary--
   This is the epilogue. It is also to be ignored.


Authors' Addresses

   Max Pritikin (editor)
   Cisco Systems, Inc.
   510 McCarthy Drive
   Milpitas, CA  95035
   USA

   Email: pritikin@cisco.com


   Peter E. Yee (editor)
   AKAYLA, Inc.
   7150 Moorland Drive
   Clarksville, MD  21029
   USA

   Email: peter@akayla.com


   Dan Harkins (editor)
   Aruba Networks
   1322 Crossman Avenue
   Sunnyvale, CA  94089-1113
   USA

   Email: dharkins@arubanetworks.com











Pritikin, et al.        Expires January 11, 2013               [Page 46]


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