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INTERNET-DRAFT                      Simon Blake-Wilson, Certicom Corp
draft-ietf-smime-ecc-05.txt         Daniel R. L. Brown, Certicom Corp
                                  Paul Lambert, Cosine Communications
7 May, 2001                                 Expires: 6 November, 2001

                      Use of ECC Algorithms in CMS

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.  Internet-Drafts are
   working documents of the Internet Engineering Task Force (IETF),
   its areas, and its working groups. Note that other groups may also
   distribute working documents as Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other
   documents at any time.  It is inappropriate to use Internet-Drafts
   as reference material or to cite them other than as "work in
   progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

Abstract

   This document describes how to use Elliptic Curve Cryptography
   (ECC) public-key algorithms in the Cryptographic Message Syntax
   (CMS).  The ECC algorithms support the creation of digital
   signatures and the exchange of keys to encrypt or authenticate
   content.  The definition of the algorithm processing is based on
   the ANSI X9.62 standard, developed by the ANSI X9F1 working group,
   and the IEEE 1363 standard and the SEC 1 standard.

   The readers attention is called to the Intellectual Property Rights
   section at the end of this document.

















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Table of Contents

   1  Introduction ........................................ 3
      1.1  Requirements terminology ....................... 3
   2  SignedData using ECC ................................ 3
      2.1  SignedData using ECDSA ......................... 3
           2.1.1  Fields of the SignedData ................ 3
           2.1.2  Actions of the sending agent ............ 4
           2.1.3  Actions of the receiving agent .......... 4
   3  EnvelopedData using ECC ............................. 5
      3.1  EnvelopedData using ECDH ....................... 5
           3.1.1  Fields of KeyAgreeRecipientInfo ......... 5
           3.1.2  Actions of the sending agent ............ 6
           3.1.3  Actions of the receiving agent .......... 6
      3.2  EnvelopedData using 1-Pass ECMQV ............... 6
           3.2.1  Fields of KeyAgreeRecipientInfo ......... 7
           3.2.2  Actions of the sending agent ............ 7
           3.2.3  Actions of the receiving agent .......... 8
   4  AuthenticatedData using ECC ............ ............ 8
      4.1  AuthenticatedData using 1-pass ECMQV ........... 8
           4.1.1  Fields of KeyAgreeRecipientInfo ......... 8
           4.1.2  Actions of the sending agent ............ 8
           4.1.3  Actions of the receiving agent .......... 9
   5  Recommended Algorithms and Elliptic Curves .......... 9
   6  Certificates using ECC .............................. 9
   7  SMIMECapabilities Attribute and ECC ................. 9
   8  ASN.1 Syntax ........................................ 10
      8.1  Algorithm identifiers .......................... 10
      8.2  Other syntax ................................... 11
   9  Summary ............................................. 13
   References ............................................. 13
   Security Considerations ................................ 14
   Intellectual Property Rights ........................... 14
   Acknowledgments ........................................ 15
   Authors' Addresses ..................................... 15
   Full Copyright Statement ............................... 16















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1  Introduction

   The Cryptographic Message Syntax (CMS) is cryptographic algorithm
   independent.  This specification defines a standard profile for the
   use of Elliptic Curve Cryptography (ECC) public key algorithms in
   the CMS.  The ECC algorithms are incorporated into the following
   CMS content types:

      - 'SignedData' to support ECC-based digital signature methods
        (ECDSA) to sign content

      - 'EnvelopedData' to support ECC-based public-key agreement
        methods (ECDH and ECMQV) to generate pairwise key-encryption
        keys to encrypt content-encryption keys used for content
        encryption

      - 'AuthenticatedData' to support ECC-based public-key agreement
        methods (ECMQV) to generate pairwise key-encryption keys to
        encrypt MAC keys used for content authentication and integrity

   Certification of EC public keys is also described to provide
   public-key distribution in support of the specified techniques.

1.1  Requirements terminology

   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 RFC 2119
   [MUST].

2  SignedData using ECC

   This section describes how to use ECC algorithms with the CMS
   SignedData format to sign data.

2.1  SignedData using ECDSA

   This section describes how to use the Elliptic Curve Digital
   Signature Algorithm (ECDSA) with SignedData.  ECDSA is specified in
   [X9.62].  The method is the elliptic curve analog of the
   Digital Signature Algorithm (DSA) [FIPS 186-2].

   In an implementation that uses ECDSA with CMS SignedData, the
   following techniques and formats MUST be used.

2.1.1  Fields of the SignedData

   When using ECDSA with SignedData the fields of SignerInfo are as in
   [CMS], but with the following restrictions:


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      digestAlgorithm MUST contain the algorithm identifier sha-1 (see
      Section 8.1) which identifies the SHA-1 hash algorithm.
      signatureAlgorithm contains the algorithm identifier
      ecdsa-with-SHA1 (see Section 8.1) which identifies the ECDSA
      signature algorithm.

      signature MUST contain the DER encoding (as an octet string) of
      a value of the ASN.1 type ECDSA-Sig-Value (see Section 8.2).

   When using ECDSA, the SignedData certificates field MAY include the
   certificate(s) for the EC public key(s) used in the generation of
   the ECDSA signatures in SignedData.  ECC certificates are discussed
   in Section 6.

2.1.2  Actions of the sending agent

   When using ECDSA with SignedData, the sending agent uses the
   message digest calculation process and signature generation process
   for SignedData that are specified in [CMS]. To sign data, the
   sending agent uses the signature method specified in [X9.62,
   Section 5.3] with the following exceptions:

      - In [X9.62, Section 5.3.1], the integer "e" is instead
        determined by converting the message digest generated
        according to [CMS, Section 5.4] to an integer using the data
        conversion method in [X9.62, Section 4.3.2].

   The sending agent encodes the resulting signature using the
   ECDSA-Sig-Value syntax (see Section 8.2) and places it in the
   SignerInfo signature field.

2.1.3  Actions of the receiving agent

   When using ECDSA with SignedData, the receiving agent uses the
   message digest calculation process and signature verification
   process for SignedData that are specified in [CMS].  To verify
   SignedData, the receiving agent uses the signature verification
   method specified in [X9.62, Section 5.4] with the following
   exceptions:

      - In [X9.62, Section 5.4.1] the integer "e'" is instead
        determined by converting the message digest generated
        according to [CMS, Section 5.4] to an integer using the data
        conversion method in [X9.62, Section 4.3.2].

   In order to verify the signature, the receiving agent retrieves the
   integers r and s from the SignerInfo signature field of the
   received message.



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3  EnvelopedData using ECC Algorithms

   This section describes how to use ECC algorithms with the CMS
   EnvelopedData format.

3.1  EnvelopedData using (ephemeral-static) ECDH

   This section describes how to use ephemeral-static Elliptic Curve
   Diffie-Hellman (ECDH) key agreement algorithm with EnvelopedData.
   Ephemeral-static ECDH is specified in [SEC1] and [IEEE1363].
   Ephemeral-static ECDH is the the elliptic curve analog of the
   ephemeral-static Diffie-Hellman key agreement algorithm specified
   jointly in the documents [CMS, Section 12.3.1.1] and [CMS-DH].

   In an implementation that uses ECDH with CMS EnvelopedData with key
   agreement, the following techniques and formats MUST be used.

3.1.1  Fields of KeyAgreeRecipientInfo

   When using ephemeral-static ECDH with EnvelopedData, the fields of
   KeyAgreeRecipientInfo are as in [CMS], but with the following
   restrictions:

      originator MUST be the alternative originatorKey.  The
      originatorKey algorithm field MUST contain the id-ecPublicKey
      object identifier (see Section 8.1) with NULL parameters.  The
      originatorKey publicKey field MUST contain the DER-encoding of a
      value of the ASN.1 type ECPoint (see Section 8.2), which
      represents the sending agent's ephemeral EC public key.

      keyEncryptionAlgorithm MUST contain the
      dhSinglePass-stdDH-sha1kdf-scheme object identifier (see Section
      8.1) if standard ECDH primitive is used, or the
      dhSinglePass-cofactorDH-sha1kdf-scheme object identifier (see
      Section 8.1) if the cofactor ECDH primitive is used.  The
      parameters field contains KeyWrapAlgorithm.  The
      KeyWrapAlgorithm is the algorithm identifier that indicates the
      symmetric encryption algorithm used to encrypt the CEK with the
      KEK.












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3.1.2  Actions of the sending agent

   When using ephemeral-static ECDH with EnvelopedData, the sending
   agent first obtains the recipient's EC public key and domain
   parameters (e.g. from the recipient's certificate).  The sending
   agent then determines an integer "keydatalen", which is the
   KeyWrapAlgorithm symmetric key-size in bits, and also a bit string
   "SharedInfo", which is the DER encoding of ECC-CMS-SharedInfo (see
   Section 8.2).  The sending agent then performs the key deployment
   and the key agreement operation of the Elliptic Curve
   Diffie-Hellman Scheme specified in [SEC1, Section 6.1].  As a
   result the sending agent obtains:

      - an ephemeral public key, which is represented as a value of
        the type ECPoint (see Section 8.2), encapsulated in a bit
        string and placed in the KeyAgreeRecipientInfo originator
        field, and

      - a shared secret bit string "K" which is used as the pairwise
        key-encryption key for that recipient, as specified in [CMS].

3.1.3  Actions of the receiving agent

   When using ephemeral-static ECDH with EnvelopedData, the receiving
   agent determines the bit string "SharedInfo", which is the DER
   encoding of ECC-CMS-SharedInfo (see Section 8.2), and the integer
   "keydatalen" from the key-size, in bits, of the KeyWrapAlgorithm.
   The receiving agent retrieves the ephemeral EC public key from the
   bit string KeyAgreeRecipientInfo originator, which an value of the
   type ECPoint (see Section 8.2) encapsulated as a bit string.  The
   receiving agent performs the key agreement operation of the
   Elliptic Curve Diffie-Hellman Scheme specified in [SEC1, Section
   6.1].  As a result the receiving agent obtains a shared secret bit
   string "K" which is used as the pairwise key-encryption key to
   unwrap the CEK.

3.2  EnvelopedData using 1-Pass ECMQV

   This section describes how to use the 1-Pass elliptic curve MQV
   (ECMQV) key agreement algorithm with EnvelopedData.  ECMQV is
   specified in [SEC1] and [IEEE1363].  Like the KEA algorithm
   [CMS-KEA], 1-Pass ECMQV uses three key pairs: an ephemeral key
   pair, a static key pair of the sending agent, and a static key pair
   of the receiving agent.  An advantage of using 1-Pass ECMQV is that
   it can be used with both EnvelopedData and AuthenticatedData.

   In an implementation that uses 1-Pass ECMQV with CMS EnvelopedData
   with key agreement, the following techniques and formats MUST be
   used.


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3.2.1  Fields of KeyAgreeRecipientInfo

   When using 1-Pass ECMQV with EnvelopedData the fields of
   KeyAgreeRecipientInfo are:

      originator identifies the static EC public key of the sender.
      It SHOULD be the one of the alternatives issuerAndSerialNumber
      or subjectKeyIdentifier and point to one of the sending agent's
      certificates.

      ukm MUST be present.  The ukm field MUST contain an octet string
      which is the DER encoding of the type MQVuserKeyingMaterial (see
      Section 8.2).  The MQVuserKeyingMaterial ephemeralPublicKey
      algorithm field MUST contain the id-ecPublicKey object
      identifier (see Section 8.1) with NULL parameters field.  The
      MQVuserKeyingMaterial ephemeralPublicKey publicKey field MUST
      contain the DER-encoding of the ASN.1 type ECPoint (see Section
      8.2) representing sending agent's ephemeral EC public key.  The
      MQVuserKeyingMaterial addedukm field, if present, SHOULD contain
      an octet string of additional user keying material of the
      sending agent.

      keyEncryptionAlgorithm MUST be the mqvSinglePass-sha1kdf-scheme
      algorithm identifier (see Section 8.1), with parameters field
      KeyWrapAlgorithm. The KeyWrapAlgorithm indicates the symmetric
      encryption algorithm used to encrypt the CEK with the KEK
      generated using the 1-Pass ECMQV algorithm.

3.2.2  Actions of the sending agent

   When using 1-Pass ECMQV with EnvelopedData, the sending agent first
   obtains the recipient's EC public key and domain parameters,
   (e.g. from the recipient's certificate) and checks that the domain
   parameters are the same.  The sending agent then determines an
   integer "keydatalen", which is the KeyWrapAlgorithm symmetric
   key-size in bits, and also a bit string "SharedInfo", which is the
   DER encoding of ECC-CMS-SharedInfo (see Section 8.2).  The sending
   agent then performs the key deployment and key agreement operations
   of the Elliptic Curve MQV Scheme specified in [SEC1, Section 6.2].
   As a result the sending agent obtains

      - an ephemeral public key, which is represented as a value of
        type ECPoint (see Section 8.2), encapsulated in a bit string,
        placed in an MQVuserKeyingMaterial ephemeralPublicKey
        publicKey field (see Section 8.2), and

      - a shared secret bit string "K" which is used as the pairwise
        key-encryption key for that recipient, as specified in [CMS].



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   The ephemeral public key can be re-used with an AuthenticatedData
   for greater efficiency.

3.2.3  Actions of the receiving agent

   When using 1-Pass ECMQV with EnvelopedData, the receiving agent
   determines the bit string "SharedInfo", which is the DER encoding
   of ECC-CMS-SharedInfo (see Section 8.2), and the integer
   "keydatalen" from the key-size, in bits, of the KeyWrapAlgorithm.
   The receiving agent then retrieves the static and ephemeral EC
   public keys of the originator, from the originator and ukm fields
   as described in Section 3.2.1, and its static EC public key
   identified in the rid field and checks that the domain parameters
   are the same.  The receiving agent then performs the key agreement
   operation of the Elliptic Curve MQV Scheme [SEC1, Section 6.2].  As
   a result the receiving agent obtains a shared secret bit string "K"
   which is used as the pairwise key-encryption key to unwrap the CEK.

4  AuthenticatedData using ECC

   This section describes how to use ECC algorithms with the CMS
   AuthenticatedData format.  AuthenticatedData lacks non-repudiation,
   and so in some instances is preferable to SignedData.  (For
   example, the sending agent might not want the message to be
   authenticated when forwarded.)

4.1  AuthenticatedData using 1-pass ECMQV

   This section describes how to use the 1-Pass elliptic curve MQV
   (ECMQV) key agreement algorithm with AuthenticatedData.  ECMQV is
   specified in [SEC1].  An advantage of using 1-Pass ECMQV is that it
   can be used with both EnvelopedData and AuthenticatedData.

4.1.1  Fields of the KeyAgreeRecipientInfo

   The AuthenticatedData KeyAgreeRecipientInfo fields are used in the
   same manner as the fields for the corresponding EnvelopedData
   KeyAgreeRecipientInfo fields of Section 3.2.1 of this document.

4.1.2  Actions of the sending agent

   The sending agent uses the same actions as for EnvelopedData
   with 1-Pass ECMQV, as specified in Section 3.2.2 of this document.

   The ephemeral public key can be re-used with an EnvelopedData for
   greater efficiency.





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   Note: if there are multiple recipients then an attack is possible
   where one recipient modifies the content without other recipients
   noticing [BON].  A sending agent who is concerned with such an
   attack SHOULD use a separate AuthenticatedData for each recipient.

4.1.3  Actions of the receiving agent

   The receiving agent uses the same actions as for EnvelopedData
   with 1-Pass ECMQV, as specified in Section 3.2.3 of this document.

   Note: see Note in Section 4.1.2.

5  Recommended Algorithms and Elliptic Curves

   Implementations of this specification MUST implement either
   SignedData with ECDSA or EnvelopedData with ephemeral-static ECDH.
   Implementations of this specification SHOULD implement both
   SignedData with ECDSA and EnvelopedData with ephemeral-static ECDH.
   Implementations MAY implement the other techniques specified, such
   as AuthenticatedData and 1-Pass ECMQV.

   Furthermore, in order to encourage interoperability,
   implementations SHOULD use the elliptic curve domain parameters
   specified by ANSI [X9.62], NIST [FIPS-186-2] and SECG [SEC2].

6  Certificates using ECC

   Internet X.509 certificates [PKI] can be used in conjunction with
   this specification to distribute agents' public keys.  The use of
   ECC algorithms and keys within X.509 certificates is specified in
   [PKI-ALG].  More details can be found in [SEC3].

7  SMIMECapabilities Attribute and ECC

   A sending agent MAY announce to receiving agents that it supports
   one or more of the ECC algorithms in this document by using the
   SMIMECapabilities signed attribute [MSG, Section 2.5.2].

   The SMIMECapability value to indicate support for the ECDSA
   signature algorithm is the SEQUENCE with the capabilityID field
   containing the object identifier ecdsa-with-SHA1 with NULL
   parameters.  The DER encoding is:

      30 0b 06 07  2a 86 48 ce   3d 04 01 05  00







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   The SMIMECapability capabilityID object identifiers for the
   supported key agreement algorithms in this document are
   dhSinglePass-stdDH-sha1kdf-scheme,
   dhSinglePass-cofactorDH-sha1kdf-scheme, and
   mqvSinglePass-sha1kdf-scheme.  For each of these SMIMECapability
   SEQUENCEs the parameters field is present and indicates the
   supported key-encryption algorithm with the KeyWrapAlgorithm
   algorithm identifier.  The DER encodings that indicate capability
   of the three key agreement algorithms with CMS Triple-DES key wrap
   are:

      30 1c 06 09  2b 81 05 10   86 48 3f 00  02 30 0f 06
      0b 2a 86 48  86 f7 0d 01   09 10 03 06  05 00

   for ephemeral-static ECDH,

      30 1c 06 09  2b 81 05 10   86 48 3f 00  03 30 0f 06
      0b 2a 86 48  86 f7 0d 01   09 10 03 06  05 00

   for ephemeral-static ECDH with cofactor method, and

      30 1c 06 09  2b 81 05 10   86 48 3f 00  10 30 0f 06
      0b 2a 86 48  86 f7 0d 01   09 10 03 06  05 00

   for ECMQV.

8  ASN.1 Syntax

   The ASN.1 syntax that is used in this document is gathered together
   in this section for reference purposes.

8.1  Algorithm identifiers

   The algorithm identifiers used in this document are taken from
   [X9.62], [SEC1] and [SEC2].

   The following object identifier indicates the hash algorithm used
   in this document:

      sha-1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
         oiw(14) secsig(3) algorithm(2) 26 }

   The following object identifier is used in this document to
   indicate an elliptic curve public key:

      id-ecPublicKey OBJECT IDENTIFIER ::= { ansi-x9-62 keyType(2) 1 }





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   where

      ansi-x9-62 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
         10045 }

   When the object identifier id-ecPublicKey is used here with an
   algorithm identifier, the associated parameters contain NULL.

   The following object identifier indicates the digital signature
   algorithm used in this document:

      ecdsa-with-SHA1 OBJECT IDENTIFIER ::= { ansi-x9-62 signatures(4)
         1 }

   When the object identifier ecdsa-with-SHA1 is used within an
   algorithm identifier, the associated parameters field contains
   NULL.

   The following object identifiers indicate the key agreement
   algorithms used in this document:

      dhSinglePass-stdDH-sha1kdf-scheme OBJECT IDENTIFIER ::= {
         x9-63-scheme 2}

      dhSinglePass-cofactorDH-sha1kdf-scheme OBJECT IDENTIFIER ::= {
         x9-63-scheme 3}

      mqvSinglePass-sha1kdf-scheme OBJECT IDENTIFIER ::= {
         x9-63-scheme 16}

   where

      x9-63-scheme OBJECT IDENTIFIER ::= { iso(1)
         identified-organization(3) tc68(133) country(16) x9(840)
         x9-63(63) schemes(0) }

   When the object identifiers are used here within an algorithm
   identifier, the associated parameters field contains the CMS
   KeyWrapAlgorithm algorithm identifier.

8.2  Other syntax

   The following additional syntax is used here.

   When using ECDSA with SignedData, ECDSA signatures are encoded
   using the type:

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

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   ECDSA-Sig-Value is specified in [X9.62].  Within CMS,
   ECDSA-Sig-Value is DER-encoded and placed within a signature field
   of SignedData.

   When using ECDH and ECMQV with EnvelopedData and AuthenticatedData,
   ephemeral and static public keys are encoded using the type
   ECPoint.

      ECPoint ::= OCTET STRING

   When using ECMQV with EnvelopedData and AuthenticatedData, the
   sending agent's ephemeral public key and additional keying material
   are encoded using the type:

      MQVuserKeyingMaterial ::= SEQUENCE {
         ephemeralPublicKey OriginatorPublicKey,
         addedukm [0] EXPLICIT UserKeyingMaterial OPTIONAL  }

   The ECPoint syntax in used to represent the ephemeral public key
   and placed in the ephemeralPublicKey field.  The additional user
   keying material is place in the addedukm field.  Then the
   MQVuserKeyingMaterial value is DER-encoded and placed within in a
   ukm field of EnvelopedData or AuthenticatedData.

   When using ECDH or ECMQV with EnvelopedData or AuthenticatedData,
   the key-encryption keys are derived by using the type:

      ECC-CMS-SharedInfo ::= SEQUENCE {
         keyInfo AlgorithmIdentifier,
         entityUInfo [0] EXPLICIT OCTET STRING OPTIONAL,
         suppPubInfo [2] EXPLICIT OCTET STRING   }

   The fields of ECC-CMS-SharedInfo are as follows:

      keyInfo contains the object identifier of the key-encryption
      algorithm (used to wrap the CEK) and NULL parameters.

      entityUInfo optionally contains additional keying material
      supplied by the sending agent.  When used with ECDH and CMS, the
      entityUInfo field contains the octet string ukm.  When used with
      ECMQV and CMS, the entityUInfo contains the octet string
      addedukm (encoded in MQVuserKeyingMaterial).

      suppPubInfo contains the length of the generated KEK, in bits,
      represented as a 32 bit number, as in [CMS-DH].  (E.g. for 3DES
      it would be 00 00 00 c0.)





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   Within CMS, ECC-CMS-SharedInfo is DER-encoded and used as input to
   the key derivation function, as specified in [SEC1, Section 3.6.1].
   Note that ECC-CMS-SharedInfo differs from the OtherInfo specified
   in [CMS-DH].  Here a counter value is not included in the keyInfo
   field because the key derivation function specified in [SEC1,
   Section 3.6.1] ensures that sufficient keying data is provided.

9  Summary

   This document specifies how to use ECC algorithms with the S/MIME
   CMS.  Use of ECC algorithm within CMS can result in reduced
   processing requirements for S/MIME agents, and reduced bandwidth
   for CMS messages.

References

   [X9.62]      ANSI X9.62-1998, "Public Key Cryptography For The
                Financial Services Industry: The Elliptic Curve
                Digital Signature Algorithm (ECDSA)", American
                National Standards Institute, 1999.

   [PKI-ALG]    L. Bassham, R. Housley and W. Polk, "Algorithms and
                Identifiers for the Internet X.509 Public Key
                Infrastructure Certificate and CRL profile", PKIX
                Working Group Internet-Draft, November 2000.

   [BON]        D. Boneh, "The Security of Multicast MAC",
                Presentation at Selected Areas of Cryptography 2000,
                Center for Applied Cryptographic Research, University
                of Waterloo, 2000.  Paper version available from
                http://crypto.stanford.edu/~dabo/papers/mmac.ps

   [MUST]       S. Bradner, "Key Words for Use in RFCs to Indicate
                Requirement Levels", RFC 2119, March 1997.

   [FIPS-180]   FIPS 180-1, "Secure Hash Standard", National Institute
                of Standards and Technology, April 17, 1995.

   [FIPS-186-2] FIPS 186-2, "Digital Signature Standard", National
                Institute of Standards and Technology, 15 February
                2000.

   [PKI]        W. Ford, R. Housley, W. Polk and D. Solo, "Internet X.509
                Public Key Infrastructure Certificate and CRL
                Profile", PKIX Working Group Internet-Draft, January
                2001.

   [CMS]        R. Housley, "Cryptographic Message Syntax", RFC 2630,
                June 1999.


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   [IEEE1363]   IEEE P1363, "Standard Specifications for Public Key
                Cryptography", Institute of Electrical and Electronics
                Engineers, 2000.

   [K]          B. Kaliski, "MQV Vulnerabilty", Posting to ANSI X9F1
                and IEEE P1363 newsgroups, 1998.

   [LMQSV]      L. Law, A. Menezes, M. Qu, J. Solinas and S. Vanstone,
                "An efficient protocol for authenticated key agreement",
                Technical report CORR 98-05, University of Waterloo,
                1998.

   [CMS-KEA]    J. Pawling, "CMS KEA and SKIPJACK Conventions", RFC
                2876, July 2000.

   [MSG]        B. Ramsdell, "S/MIME Version 3 Message Specification",
                RFC 2633, June 1999.

   [CMS-DH]     E. Rescorla, "Diffie-Hellman Key Agreement Method",
                RFC 2631, June 1999.

   [SEC1]       SECG, "Elliptic Curve Cryptography", Standards for
                Efficient Cryptography Group, 2000.

   [SEC2]       SECG, "Recommended Elliptic Curve Domain Parameters",
                Standards for Efficient Cryptography Group, 2000.

Security Considerations

   This specification is based on [CMS], [X9.62] and [SEC1] and the
   appropriate security considerations of those documents apply.

   In addition, implementors of AuthenticatedData should be aware of
   the concerns expressed in [BON] when using AuthenticatedData to
   send messages to more than one recipient.  Also, users of MQV
   should be aware of the vulnerability in [K].

   When 256, 384, and 512 bit hash functions succeed SHA-1 in future
   revisions of [FIPS], [FIPS-186-2], [X9.62] and [SEC1], then they
   can similarly succeed SHA-1 in a future revision of this document.

Intellectual Property Rights

   The IETF has been notified of intellectual property rights claimed
   in regard to the specification contained in this document.  For
   more information, consult the online list of claimed rights
   (http://www.ietf.org/ipr.html).




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   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; neither does it represent that it
   has made any effort to identify any such rights. Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in BCP-11. Copies of
   claims of rights made available for publication and any assurances
   of licenses to be made available, or the result of an attempt made
   to obtain a general license or permission for the use of such
   proprietary rights by implementors or users of this specification
   can be obtained from the IETF Secretariat.

Acknowledgments

   The methods described in this document are based on work done by
   the ANSI X9F1 working group.  The authors wish to extend their
   thanks to ANSI X9F1 for their assistance.  The authors also wish to
   thank Peter de Rooij for his patient assistance.  The technical
   comments of Francois Rousseau were valuable contributions.

Authors' Addresses

   Simon Blake-Wilson
   Certicom Corp
   5520 Explorer Drive #400
   Mississauga, ON L4W 5L1

   e-mail: sblakewi@certicom.com


   Daniel R. L. Brown
   Certicom Corp
   5520 Explorer Drive #400
   Mississauga, ON L4W 5L1

   e-mail: dbrown@certicom.com


   Paul Lambert
   Director of Security Applications
   CoSine Communications
   1200 Bridge Parkway
   Redwood City, CA, 94065
   http://www.cosinecom.com

   e-mail: plambert@cosinecom.com



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Full Copyright Statement

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