    Internet Engineering Task Force (IETF)                         S. Turner
    Request for Comments: 5753                                          IECA
    Obsoletes: 3278                                                 D. Brown
    Category: Informational                                         Certicom
    ISSN: 2070-1721                                             January 2010

              Use of Elliptic Curve Cryptography (ECC) Algorithms
                     in Cryptographic Message Syntax (CMS)

    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 NIST FIPS 186-3 for
       digital signature, NIST SP800-56A and SEC1 for key agreement, RFC
       3370 and RFC 3565 for key wrap and content encryption, NIST FIPS
       180-3 for message digest, SEC1 for key derivation, and RFC 2104 and
       RFC 4231 for message authentication code standards.  This document
       obsoletes RFC 3278.

    Status of This Memo

       This document is not an Internet Standards Track specification; it is
       published for informational purposes.

       This document is a product of the Internet Engineering Task Force
       (IETF).  It represents the consensus of the IETF community.  It has
       received public review and has been approved for publication by the
       Internet Engineering Steering Group (IESG).  Not all documents
       approved by the IESG are a candidate for any level of Internet
       Standard; see Section 2 of RFC 5741.

       Information about the current status of this document, any errata,
       and how to provide feedback on it may be obtained at
       http://www.rfc-editor.org/info/rfc5753.

    Copyright Notice

       Copyright (c) 2010 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.

       This document may contain material from IETF Documents or IETF
       Contributions published or made publicly available before November
       10, 2008.  The person(s) controlling the copyright in some of this
       material may not have granted the IETF Trust the right to allow
       modifications of such material outside the IETF Standards Process.
       Without obtaining an adequate license from the person(s) controlling
       the copyright in such materials, this document may not be modified
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       not be created outside the IETF Standards Process, except to format
       it for publication as an RFC or to translate it into languages other
       than English.

    Table of Contents

       1. Introduction ....................................................3
          1.1. Requirements Terminology ...................................3
       2. SignedData Using ECC ............................................3
          2.1. SignedData Using ECDSA .....................................4
       3. EnvelopedData Using ECC Algorithms ..............................5
          3.1. EnvelopedData Using (ephemeral-static) ECDH ................5
          3.2. EnvelopedData Using 1-Pass ECMQV ...........................8
       4. AuthenticatedData and AuthEnvelopedData Using ECC ..............11
          4.1. AuthenticatedData Using 1-Pass ECMQV ......................11
          4.2. AuthEnvelopedData Using 1-Pass ECMQV ......................12
       5. Certificates Using ECC .........................................13
       6. SMIMECapabilities Attribute and ECC ............................13
       7. ASN.1 Syntax ...................................................21
          7.1. Algorithm Identifiers .....................................21
          7.2. Other Syntax ..............................................24
       8. Recommended Algorithms and Elliptic Curves .....................26
       9. Security Considerations ........................................28
       10. IANA Considerations ...........................................33
       11. References ....................................................33
          11.1. Normative References .....................................33
          11.2. Informative References ...................................35
       Appendix A.  ASN.1 Modules.........................................37
          A.1.  1988 ASN.1 Module.........................................37
          A.2.  2004 ASN.1 Module.........................................45
       Appendix B. Changes since RFC 3278.................................59
       Acknowledgements...................................................61

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    1.  Introduction

       The Cryptographic Message Syntax (CMS) is cryptographic algorithm
       independent.  This specification defines a 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 message-authentication keys used for content
          authentication and integrity; and

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

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

       The document will obsolete [CMS-ECC].  The technical changes
       performed since RFC 3278 are detailed in Appendix B.

    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 [MUST].

    2.  SignedData Using ECC

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

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    2.1.  SignedData Using ECDSA

       This section describes how to use the Elliptic Curve Digital
       Signature Algorithm (ECDSA) with SignedData.  ECDSA is specified in
       [FIPS186-3].  The method is the elliptic curve analog of the Digital
       Signature Algorithm (DSA) [FIPS186-3].  ECDSA is used with the Secure
       Hash Algorithm (SHA) [FIPS180-3].

       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:

       -  digestAlgorithm MUST contain the algorithm identifier of the hash
          algorithm (see Section 7.1.1), which MUST be one of the following:
          id-sha1, id-sha224, id-sha256, id-sha384, or id-sha512.

       -  signatureAlgorithm contains the signature algorithm identifier
          (see Section 7.1.3): ecdsa-with-SHA1, ecdsa-with-SHA224, ecdsa-
          with-SHA256, ecdsa-with-SHA384, or ecdsa-with-SHA512.  The hash
          algorithm identified in the name of the signature algorithm MUST
          be the same as the digestAlgorithm (e.g., digestAlgorithm is id-
          sha256 therefore signatureAlgorithm is ecdsa-with-SHA256).

       -  signature MUST contain the DER encoding (as an octet string) of a
          value of the ASN.1 type ECDSA-Sig-Value (see Section 7.2).

       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 5.

    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 [FIPS186-3].

       The sending agent encodes the resulting signature using the ECDSA-
       Sig-Value syntax (see Section 7.2) and places it in the SignerInfo
       signature field.

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    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 [FIPS186-3].

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

    3.  EnvelopedData Using ECC Algorithms

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

       This document does not specify the static-static ECDH, method C(0,2,
       ECC CDH) from [SP800-56A].  Static-static ECDH is analogous to
       static-static DH, which is specified in [CMS-ALG].  Ephemeral-static
       ECDH and 1-Pass ECMQV were specified because they provide better
       security due to the originator's ephemeral contribution to the key
       agreement scheme.

    3.1.  EnvelopedData Using (ephemeral-static) ECDH

       This section describes how to use the ephemeral-static Elliptic Curve
       Diffie-Hellman (ECDH) key agreement algorithm with EnvelopedData.
       This algorithm has two variations:

       - 'Standard' ECDH, described as the 'Elliptic Curve Diffie-Hellman
         Scheme' with the 'Elliptic Curve Diffie-Hellman Primitive' in
         [SEC1], and

       - 'Co-factor' ECDH, described as the 'One-Pass Diffie-Hellman scheme'
         (method C(1, 1, ECC CDH)) in [SP800-56A].

       Both variations of ephemeral-static ECDH are elliptic curve analogs
       of the ephemeral-static Diffie-Hellman key agreement algorithm
       specified jointly in the documents [CMS-ALG] and [CMS-DH].

       If an implementation uses ECDH with CMS EnvelopedData, then the
       following techniques and formats MUST be used.

       The fields of EnvelopedData are as in [CMS]; as ECDH is a key
       agreement algorithm, the RecipientInfo kari choice is used.

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    3.1.1.  Fields of KeyAgreeRecipientInfo

       When using ephemeral-static ECDH with EnvelopedData, the fields of
       KeyAgreeRecipientInfo are as follows:

       -  version MUST be 3.

       -  originator MUST be the alternative originatorKey.  The
          originatorKey algorithm field MUST contain the id-ecPublicKey
          object identifier (see Section 7.1.2).  The parameters associated
          with id-ecPublicKey MUST be absent, ECParameters, or NULL.  The
          parameters associated with id-ecPublicKey SHOULD be absent or
          ECParameters, and NULL is allowed to support legacy
          implementations.  The previous version of this document required
          NULL to be present.  If the parameters are ECParameters, then they
          MUST be namedCurve.  The originatorKey publicKey field MUST
          contain the DER encoding of the value of the ASN.1 type ECPoint
          (see Section 7.2), which represents the sending agent's ephemeral
          EC public key.  The ECPoint in uncompressed form MUST be
          supported.

       -  ukm MAY be present or absent.  However, message originators SHOULD
          include the ukm.  As specified in RFC 3852 [CMS], implementations
          MUST support ukm message recipient processing, so interoperability
          is not a concern if the ukm is present or absent.  The ukm is
          placed in the entityUInfo field of the ECC-CMS-SharedInfo
          structure.  When present, the ukm is used to ensure that a
          different key-encryption key is generated, even when the ephemeral
          private key is improperly used more than once, by using the ECC-
          CMS-SharedInfo as an input to the key derivation function (see
          Section 7.2).

       -  keyEncryptionAlgorithm MUST contain the object identifier of the
          key-encryption algorithm, which in this case is a key agreement
          algorithm (see Section 7.1.4).  The parameters field contains
          KeyWrapAlgorithm.  The KeyWrapAlgorithm is the algorithm
          identifier that indicates the symmetric encryption algorithm used
          to encrypt the content-encryption key (CEK) with the key-
          encryption key (KEK) and any associated parameters (see Section
          7.1.5).  Algorithm requirements are found in Section 8.

       -  recipientEncryptedKeys contains an identifier and an encrypted key
          for each recipient.  The RecipientEncryptedKey
          KeyAgreeRecipientIdentifier MUST contain either the
          issuerAndSerialNumber identifying the recipient's certificate or
          the RecipientKeyIdentifier containing the subject key identifier
          from the recipient's certificate.  In both cases, the recipient's
          certificate contains the recipient's static ECDH public key.

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          RecipientEncryptedKey EncryptedKey MUST contain the content-
          encryption key encrypted with the ephemeral-static, ECDH-generated
          pairwise key-encryption key using the algorithm specified by the
          KeyWrapAlgorithm.

    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 performs one of the two ECDH variations mentioned above:

       - If the value of keyEncryptionAlgorithm indicates the use of
         'standard' Diffie-Hellman, then the sending agent performs the
         'Elliptic Curve Diffie-Hellman Scheme' with the 'Elliptic Curve
         Diffie-Hellman Primitive' in [SEC1].

       - If the value of keyEncryptionAlgorithm indicates the use of 'co-
         factor' Diffie-Hellman, then the sending agent performs the 'One-
         Pass Diffie-Hellman scheme' (method C(1, 1, ECC CDH)) in
         [SP800-56A].

       In both of these cases, the sending agent uses the KDF defined in
       Section 3.6.1 of [SEC1] with the hash algorithm identified by the
       value of keyEncryptionAlgorithm.  As a result, the sending agent
       obtains:

       -  an ephemeral public key, which is represented as a value of the
          type ECPoint (see Section 7.2), encapsulated in a bit string and
          placed in the KeyAgreeRecipientInfo originator originatorKey
          publicKey field, and

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

       In a single message, if there are multiple layers for a recipient,
       then the ephemeral public key can be reused by the originator for
       that recipient in each of the different layers.

    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 7.2), 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, with a value of the type
       ECPoint (see Section 7.2) encapsulated as a bit string, and if

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       present, originally supplied additional user key material from the
       ukm field.  The receiving agent then performs one of the two ECDH
       variations mentioned above:

       - If the value of keyEncryptionAlgorithm indicates the use of
         'standard' Diffie-Hellman, then the receiving agent performs the
         'Elliptic Curve Diffie-Hellman Scheme' with the 'Elliptic Curve
         Diffie-Hellman Primitive' in [SEC1].

       - If the value of keyEncryptionAlgorithm indicates the use of 'co-
         factor' Diffie-Hellman, then the receiving agent performs the 'One-
         Pass Diffie-Hellman scheme' (method C(1, 1, ECC CDH)) in
         [SP800-56A].

       In both of these cases, the receiving agent uses the KDF defined in
       Section 3.6.1 of [SEC1] with the hash algorithm identified by the
       value of keyEncryptionAlgorithm.  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 Menezes-
       Qu-Vanstone (ECMQV) key agreement algorithm with EnvelopedData,
       method C(1, 2, ECC MQV) from [SP800-56A].  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.  Using an algorithm with the sender static key pair
       allows for knowledge of the message creator; this means that
       authentication can, in some circumstances, be obtained for
       AuthEnvelopedData and AuthenticatedData.  This means that 1-Pass
       ECMQV can be a common algorithm for EnvelopedData, AuthenticatedData,
       and AuthEnvelopedData, while ECDH can only be used in EnvelopedData.

       If an implementation uses 1-Pass ECMQV with CMS EnvelopedData, then
       the following techniques and formats MUST be used.

       The fields of EnvelopedData are as in [CMS]; as 1-Pass ECMQV is a key
       agreement algorithm, the RecipientInfo kari choice is used.  When
       using 1-Pass ECMQV, the EnvelopedData originatorInfo field MAY
       include the certificate(s) for the EC public key(s) used in the
       formation of the pairwise key.  ECC certificates are discussed in
       Section 5.

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    3.2.1.  Fields of KeyAgreeRecipientInfo

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

       -  version MUST be 3.

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

       -  ukm MUST be present.  The ukm field is an octet string that MUST
          contain the DER encoding of the type MQVuserKeyingMaterial (see
          Section 7.2).  The MQVuserKeyingMaterial ephemeralPublicKey
          algorithm field MUST contain the id-ecPublicKey object identifier
          (see Section 7.1.2).  The parameters associated with id-
          ecPublicKey MUST be absent, ECParameters, or NULL.  The parameters
          associated with id-ecPublicKey SHOULD be absent or ECParameters,
          as NULL is allowed to support legacy implementations.  The
          previous version of this document required NULL to be present.  If
          the parameters are ECParameters, then they MUST be namedCurve.
          The MQVuserKeyingMaterial ephemeralPublicKey publicKey field MUST
          contain the DER encoding of the ASN.1 type ECPoint (see Section
          7.2) representing the sending agent's ephemeral EC public key.
          The MQVuserKeyingMaterial addedukm field, if present, contains
          additional user keying material from the sending agent.

       -  keyEncryptionAlgorithm MUST contain the object identifier of the
          key-encryption algorithm, which in this case is a key agreement
          algorithm (see Section 7.1.4).  The parameters field contains
          KeyWrapAlgorithm.  The KeyWrapAlgorithm indicates the symmetric
          encryption algorithm used to encrypt the CEK with the KEK
          generated using the 1-Pass ECMQV algorithm and any associated
          parameters (see Section 7.1.5).  Algorithm requirements are found
          in Section 8.

       -  recipientEncryptedKeys contains an identifier and an encrypted key
          for each recipient.  The RecipientEncryptedKey
          KeyAgreeRecipientIdentifier MUST contain either the
          issuerAndSerialNumber identifying the recipient's certificate or
          the RecipientKeyIdentifier containing the subject key identifier
          from the recipient's certificate.  In both cases, the recipient's
          certificate contains the recipient's static ECMQV public key.
          RecipientEncryptedKey EncryptedKey MUST contain the content-
          encryption key encrypted with the 1-Pass ECMQV-generated pairwise
          key-encryption key using the algorithm specified by the
          KeyWrapAlgorithm.

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    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 as the sender's domain parameters.  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 7.2).  The sending agent then performs the key deployment and
       key agreement operations of the Elliptic Curve MQV Scheme specified
       in [SP800-56A], but uses the KDF defined in Section 3.6.1 of [SEC1].
       As a result, the sending agent obtains:

       - an ephemeral public key, which is represented as a value of type
         ECPoint (see Section 7.2), encapsulated in a bit string, placed in
         an MQVuserKeyingMaterial ephemeralPublicKey publicKey field (see
         Section 7.2), and

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

       In a single message, if there are multiple layers for a recipient,
       then the ephemeral public key can be reused by the originator for
       that recipient in each of the different layers.

    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 7.2), 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 originator's domain parameters are the same
       as the recipient's domain parameters.  The receiving agent then
       performs the key agreement operation of the Elliptic Curve MQV Scheme
       [SP800-56A], but uses the KDF defined in Section 3.6.1 of [SEC1].  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.

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    4.  AuthenticatedData and AuthEnvelopedData 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.)

       This section also describes how to use ECC algorithms with the CMS
       AuthEnvelopedData format [CMS-AUTHENV].  AuthEnvelopedData supports
       authentication and encryption, and in some instances is preferable to
       signing and then encrypting data.

       For both AuthenticatedData and AuthEnvelopedData, data origin
       authentication with 1-Pass ECMQV can only be provided when there is
       one and only one recipient.  When there are multiple recipients, 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 or
       AuthEnvelopedData for each recipient.

       Using an algorithm with the sender static key pair allows for
       knowledge of the message creator; this means that authentication can,
       in some circumstances, be obtained for AuthEnvelopedData and
       AuthenticatedData.  This means that 1-Pass ECMQV can be a common
       algorithm for EnvelopedData, AuthenticatedData, and AuthEnvelopedData
       while ECDH can only be used in EnvelopedData.

    4.1.  AuthenticatedData Using 1-Pass ECMQV

       This section describes how to use the 1-Pass ECMQV key agreement
       algorithm with AuthenticatedData.  ECMQV is method C(1, 2, ECC MQV)
       from [SP800-56A].

       When using ECMQV with AuthenticatedData, the fields of
       AuthenticatedData are as in [CMS], but with the following
       restrictions:

       - macAlgorithm MUST contain the algorithm identifier of the message
         authentication code (MAC) algorithm (see Section 7.1.7), which MUST
         be one of the following: hmac-SHA1, id-hmacWITHSHA224, id-
         hmacWITHSHA256, id-hmacWITHSHA384, or id-hmacWITHSHA512.

       - digestAlgorithm MUST contain the algorithm identifier of the hash
         algorithm (see Section 7.1.1), which MUST be one of the following:
         id-sha1, id-sha224, id-sha256, id-sha384, or id-sha512.

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       As 1-Pass ECMQV is a key agreement algorithm, the RecipientInfo kari
       choice is used in the AuthenticatedData.  When using 1-Pass ECMQV,
       the AuthenticatedData originatorInfo field MAY include the
       certificate(s) for the EC public key(s) used in the formation of the
       pairwise key.  ECC certificates are discussed in Section 5.

    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.

       In a single message, if there are multiple layers for a recipient,
       then the ephemeral public key can be reused by the originator for
       that recipient in each of the different layers.

    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.

    4.2.  AuthEnvelopedData Using 1-Pass ECMQV

       This section describes how to use the 1-Pass ECMQV key agreement
       algorithm with AuthEnvelopedData.  ECMQV is method C(1, 2, ECC MQV)
       from [SP800-56A].

       When using ECMQV with AuthEnvelopedData, the fields of
       AuthEnvelopedData are as in [CMS-AUTHENV].

       As 1-Pass ECMQV is a key agreement algorithm, the RecipientInfo kari
       choice is used.  When using 1-Pass ECMQV, the AuthEnvelopedData
       originatorInfo field MAY include the certificate(s) for the EC public
       key used in the formation of the pairwise key.  ECC certificates are
       discussed in Section 5.

    4.2.1.  Fields of the KeyAgreeRecipientInfo

       The AuthEnvelopedData 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.

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    4.2.2.  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.

       In a single message, if there are multiple layers for a recipient,
       then the ephemeral public key can be reused by the originator for
       that recipient in each of the different layers.

    4.2.3.  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.

    5.  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].

    6.  SMIMECapabilities Attribute and ECC

       A sending agent MAY announce to receiving agents that it supports one
       or more of the ECC algorithms specified in this document by using the
       SMIMECapabilities signed attribute [MSG] in either a signed message
       or a certificate [CERTCAP].

       The SMIMECapabilities attribute value indicates support for one of
       the ECDSA signature algorithms in a SEQUENCE with the capabilityID
       field containing the object identifier ecdsa-with-SHA1 with NULL
       parameters and ecdsa-with-SHA* (where * is 224, 256, 384, or 512)
       with absent parameters.  The DER encodings are:

          ecdsa-with-SHA1:   30 0b 06 07 2a 86 48 ce 3d 04 01 05 00

          ecdsa-with-SHA224: 30 0a 06 08 2a 86 48 ce 3d 04 03 01

          ecdsa-with-SHA256: 30 0a 06 08 2a 86 48 ce 3d 04 03 02

          ecdsa-with-SHA384: 30 0a 06 08 2a 86 48 ce 3d 04 03 03

          ecdsa-with-SHA512: 30 0a 06 08 2a 86 48 ce 3d 04 03 04

       NOTE: The SMIMECapabilities attribute indicates that parameters for
       ECDSA with SHA-1 are NULL; however, the parameters are absent when
       used to generate a digital signature.

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       The SMIMECapabilities attribute value indicates support for

          a)  the standard ECDH key agreement algorithm,
          b)  the cofactor ECDH key agreement algorithm, or
          c)  the 1-Pass ECMQV key agreement algorithm and

       is a SEQUENCE with the capabilityID field containing the object
       identifier

          a)  dhSinglePass-stdDH-sha*kdf-scheme,
          b)  dhSinglePass-cofactorDH-sha*kdf-scheme, or
          c)  mqvSinglePass-sha*kdf-scheme

       respectively (where * is 1, 224, 256, 384, or 512) with the
       parameters present.  The parameters indicate the supported key-
       encryption algorithm with the KeyWrapAlgorithm algorithm identifier.

       The DER encodings that indicate capabilities are as follows (KA is
       key agreement, KDF is key derivation function, and Wrap is key wrap
       algorithm):

          KA=ECDH standard KDF=SHA-1 Wrap=Triple-DES

            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

          KA=ECDH standard KDF=SHA-224 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0B 00 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECDH standard KDF=SHA-256 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0B 01 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECDH standard KDF=SHA-384 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0B 02 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECDH standard KDF=SHA-512 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0B 03 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

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          KA=ECDH standard KDF=SHA-1 Wrap=AES-128

            30 18 06 09 2b 81 05 10 86 48 3f 00 02 30 0b 06 09 60 86 48 01
            65 03 04 01 05

          KA=ECDH standard KDF=SHA-224 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0B 00 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECDH standard KDF=SHA-256 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0B 01 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECDH standard KDF=SHA-384 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0B 02 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECDH standard KDF=SHA-512 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0B 03 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECDH standard KDF=SHA-1 Wrap=AES-192

            30 18 06 09 2b 81 05 10 86 48 3f 00 02 30 0b 06 09 60 86 48 01
            65 03 04 01 19

          KA=ECDH standard KDF=SHA-224 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0B 00 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECDH standard KDF=SHA-256 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0B 01 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECDH standard KDF=SHA-384 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0B 02 30 0b 06 09 60 86 48 01 65 03 04
            01 19

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          KA=ECDH standard KDF=SHA-512 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0B 03 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECDH standard KDF=SHA-1 Wrap=AES-256

            30 18 06 09 2b 81 05 10 86 48 3f 00 02 30 0b 06 09 60 86 48 01
            65 03 04 01 2D

          KA=ECDH standard KDF=SHA-224 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0B 00 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECDH standard KDF=SHA-256 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0B 01 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECDH standard KDF=SHA-384 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0B 02 30 0b 06 09 60 86 48 01 65 03 04
            01 2D 05 00

          KA=ECDH standard KDF=SHA-512 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0B 03 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECDH cofactor KDF=SHA-1 Wrap=Triple-DES

            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

          KA=ECDH cofactor KDF=SHA-224 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0E 00 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECDH cofactor KDF=SHA-256 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0E 01 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

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          KA=ECDH cofactor KDF=SHA-384 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0E 02 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECDH cofactor KDF=SHA-512 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0E 03 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECDH cofactor KDF=SHA-1 Wrap=AES-128

            30 18 06 09 2b 81 05 10 86 48 3f 00 03 30 0b 06 09 60 86 48 01
            65 03 04 01 05

          KA=ECDH cofactor KDF=SHA-224 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0E 00 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECDH cofactor KDF=SHA-256 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0E 01 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECDH cofactor KDF=SHA-384 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0E 02 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECDH cofactor KDF=SHA-512 Wrap=AES-128

            30 17 06 06 2b 81 04 01 0E 03 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECDH cofactor KDF=SHA-1 Wrap=AES-192

            30 18 06 09 2b 81 05 10 86 48 3f 00 03 30 0b 06 09 60 86 48 01
            65 03 04 01 19

          KA=ECDH cofactor KDF=SHA-224 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0E 00 30 0b 06 09 60 86 48 01 65 03 04
            01 19

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          KA=ECDH cofactor KDF=SHA-256 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0E 01 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECDH cofactor KDF=SHA-384 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0E 02 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECDH cofactor KDF=SHA-512 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0E 03 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECDH cofactor KDF=SHA-1 Wrap=AES-256

            30 15 06 09 2b 81 05 10 86 48 3f 00 03 30 0b 06 09 60 86 48 01
            65 03 04 01 2D

          KA=ECDH cofactor KDF=SHA-224 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0E 00 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECDH cofactor KDF=SHA-256 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0E 01 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECDH cofactor KDF=SHA-384 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0E 02 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECDH cofactor KDF=SHA-512 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0E 03 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECMQV 1-Pass KDF=SHA-1 Wrap=Triple-DES

            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

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          KA=ECMQV 1-Pass KDF=SHA-224 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0F 00 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECMQV 1-Pass KDF=SHA-256 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0F 01 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECMQV 1-Pass KDF=SHA-384 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0F 02 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECMQV 1-Pass KDF=SHA-512 Wrap=Triple-DES

            30 17 06 06 2b 81 04 01 0F 03 30 0d 06 0b 2a 86 48 86 f7 0d 01
            09 10 03 06

          KA=ECMQV 1-Pass KDF=SHA-1 Wrap=AES-128

            30 18 06 09 2b 81 05 10 86 48 3f 00 10 30 0b 06 09 60 86 48 01
            65 03 04 01 05

          KA=ECMQV 1-Pass KDF=SHA-224 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0F 00 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECMQV 1-Pass KDF=SHA-256 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0F 01 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECMQV 1-Pass KDF=SHA-384 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0F 02 30 0b 06 09 60 86 48 01 65 03 04
            01 05

          KA=ECMQV 1-Pass KDF=SHA-512 Wrap=AES-128

            30 15 06 06 2b 81 04 01 0F 03 30 0b 06 09 60 86 48 01 65 03 04
            01 05

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          KA=ECMQV 1-Pass KDF=SHA-1 Wrap=AES-192

            30 18 06 09 2b 81 05 10 86 48 3f 00 10 30 0b 06 09 60 86 48 01
            65 03 04 01 19

          KA=ECMQV 1-Pass KDF=SHA-224 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0F 00 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECMQV 1-Pass KDF=SHA-256 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0F 01 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECMQV 1-Pass KDF=SHA-384 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0F 02 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECMQV 1-Pass KDF=SHA-512 Wrap=AES-192

            30 15 06 06 2b 81 04 01 0F 03 30 0b 06 09 60 86 48 01 65 03 04
            01 19

          KA=ECMQV 1-Pass KDF=SHA-1 Wrap=AES-256

            30 18 06 09 2b 81 05 10 86 48 3f 00 10 30 0b 06 09 60 86 48 01
            65 03 04 01 2D

          KA=ECMQV 1-Pass KDF=SHA-224 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0F 00 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECMQV 1-Pass KDF=SHA-256 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0F 01 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

          KA=ECMQV 1-Pass KDF=SHA-384 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0F 02 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

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          KA=ECMQV 1-Pass KDF=SHA-512 Wrap=AES-256

            30 15 06 06 2b 81 04 01 0F 03 30 0b 06 09 60 86 48 01 65 03 04
            01 2D

       NOTE: The S/MIME Capabilities for the supported AES content-
       encryption key sizes are defined in [CMS-AES].

       NOTE: The S/MIME Capabilities for the supported MAC algorithms are
       defined in [CMS-ASN].

    7.  ASN.1 Syntax

       The ASN.1 syntax [X.680], [X.681], [X.682], [X.683] used in this
       document is gathered in this section for reference purposes.

    7.1.  Algorithm Identifiers

       This section provides the object identifiers for the algorithms used
       in this document along with any associated parameters.

    7.1.1.  Digest Algorithms

       Digest algorithm object identifiers are used in the SignedData
       digestAlgorithms and digestAlgorithm fields and the AuthenticatedData
       digestAlgorithm field.  The digest algorithms used in this document
       are SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512.  The object
       identifiers and parameters associated with these algorithms are found
       in [CMS-ALG] and [CMS-SHA2].

    7.1.2.  Originator Public Key

       The KeyAgreeRecipientInfo originator field uses the following object
       identifier to indicate an elliptic curve public key:

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

       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 MUST be either absent
       or ECParameters.  Implementations MUST accept id-ecPublicKey with
       absent and ECParameters parameters.  If ECParameters is present, its

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       value MUST match the recipient's ECParameters.  Implementations
       SHOULD generate absent parameters for the id-ecPublicKey object
       identifier in the KeyAgreeRecipientInfo originator field.

       [CMS-ECC] indicated the parameters were NULL.  Support for this
       legacy form is OPTIONAL.

    7.1.3.  Signature Algorithms

       Signature algorithm identifiers are used in the SignedData
       signatureAlgorithm and signature fields.  The signature algorithms
       used in this document are ECDSA with SHA-1, ECDSA with SHA-224, ECDSA
       with SHA-256, ECDSA with SHA-384, and ECDSA with SHA-512.  The object
       identifiers and parameters associated with these algorithms are found
       in [PKI-ALG].

       [CMS-ECC] indicated the parameters were NULL.  Support for this
       legacy form is OPTIONAL.

    7.1.4.  Key Agreement Algorithms

       Key agreement algorithms are used in EnvelopedData,
       AuthenticatedData, and AuthEnvelopedData in the KeyAgreeRecipientInfo
       keyEncryptionAlgorithm field.  The following object identifiers
       indicate the key agreement algorithms used in this document
       [SP800-56A], [SEC1]:

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

          dhSinglePass-stdDH-sha224kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 11 0 }

          dhSinglePass-stdDH-sha256kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 11 1 }

          dhSinglePass-stdDH-sha384kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 11 2 }

          dhSinglePass-stdDH-sha512kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 11 3 }

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

          dhSinglePass-cofactorDH-sha224kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 14 0 }

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          dhSinglePass-cofactorDH-sha256kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 14 1 }

          dhSinglePass-cofactorDH-sha384kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 14 2 }

          dhSinglePass-cofactorDH-sha512kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 14 3 }

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

          mqvSinglePass-sha224kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 15 0 }

          mqvSinglePass-sha256kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 15 1 }

          mqvSinglePass-sha384kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 15 2 }

          mqvSinglePass-sha512kdf-scheme OBJECT IDENTIFIER ::= {
            secg-scheme 15 3 }

       where

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

       and

          secg-scheme OBJECT IDENTIFIER ::= {
            iso(1) identified-organization(3) certicom(132) schemes(1) }

       When the object identifiers are used here within an algorithm
       identifier, the associated parameters field contains KeyWrapAlgorithm
       to indicate the key wrap algorithm and any associated parameters.

    7.1.5.  Key Wrap Algorithms

       Key wrap algorithms are used as part of the parameters in the key
       agreement algorithm.  The key wrap algorithms used in this document
       are Triple-DES, AES-128, AES-192, and AES-256.  The object
       identifiers and parameters for these algorithms are found in
       [CMS-ALG] and [CMS-AES].

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    7.1.6.  Content Encryption Algorithms

       Content encryption algorithms are used in EnvelopedData and
       AuthEnvelopedData in the EncryptedContentInfo
       contentEncryptionAlgorithm field.  The content encryption algorithms
       used with EnvelopedData in this document are 3-Key Triple DES in CBC
       mode, AES-128 in CBC mode, AES-192 in CBC mode, and AES-256 in CBC
       mode.  The object identifiers and parameters associated with these
       algorithms are found in [CMS-ALG] and [CMS-AES].  The content
       encryption algorithms used with AuthEnvelopedData in this document
       are AES-128 in CCM mode, AES-192 in CCM mode, AES-256 in CCM mode,
       AES-128 in GCM mode, AES-192 in GCM mode, and AES-256 in GCM mode.
       The object identifiers and parameters associated with these
       algorithms are found in [CMS-AESCG].

    7.1.7.  Message Authentication Code Algorithms

       Message authentication code algorithms are used in AuthenticatedData
       in the macAlgorithm field.  The message authentication code
       algorithms used in this document are HMAC with SHA-1, HMAC with
       SHA-224, HMAC with SHA-256, HMAC with SHA-384, and HMAC with SHA-512.
       The object identifiers and parameters associated with these
       algorithms are found in [CMS-ALG] and [HMAC-SHA2].

       NOTE: [HMAC-SHA2] defines the object identifiers for HMAC with
       SHA-224, HMAC with SHA-256, HMAC with SHA-384, and HMAC with SHA-512,
       but there is no ASN.1 module from which to import these object
       identifiers.  Therefore, the object identifiers for these algorithms
       are included in the ASN.1 modules defined in Appendix A.

    7.1.8.  Key Derivation Algorithm

       The KDF used in this document is as specified in Section 3.6.1 of
       [SEC1].  The hash algorithm is identified in the key agreement
       algorithm.  For example, dhSinglePass-stdDH-sha256kdf-scheme uses the
       KDF from [SEC1] but uses SHA-256 instead of SHA-1.

    7.2.  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 [PKI-ALG].  Within CMS, ECDSA-Sig-
       Value is DER-encoded and placed within a signature field of
       SignedData.

       When using ECDH and ECMQV with EnvelopedData, AuthenticatedData, and
       AuthEnvelopedData, ephemeral and static public keys are encoded using
       the type ECPoint.  Implementations MUST support uncompressed keys,
       MAY support compressed keys, and MUST NOT support hybrid keys.

          ECPoint ::= OCTET STRING

       When using ECMQV with EnvelopedData, AuthenticatedData, and
       AuthEnvelopedData, 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 is used to represent the ephemeral public key and
       is placed in the ephemeralPublicKey publicKey field.  The additional
       user keying material is placed in the addedukm field.  Then the
       MQVuserKeyingMaterial value is DER-encoded and placed within the ukm
       field of EnvelopedData, AuthenticatedData, or AuthEnvelopedData.

       When using ECDH or ECMQV with EnvelopedData, AuthenticatedData, or
       AuthEnvelopedData, 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 associated parameters.  In
          this specification, 3DES wrap has NULL parameters while the AES
          wraps have absent 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).

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

          suppPubInfo contains the length of the generated KEK, in bits,
          represented as a 32-bit number, as in [CMS-DH] and [CMS-AES].
          (For example, for AES-256 it would be 00 00 01 00.)

       Within CMS, ECC-CMS-SharedInfo is DER-encoded and used as input to
       the key derivation function, as specified in Section 3.6.1 of [SEC1].

       NOTE: 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 Section 3.6.1 of
       [SEC1] ensures that sufficient keying data is provided.

    8.  Recommended Algorithms and Elliptic Curves

       It is RECOMMENDED that implementations of this specification support
       SignedData and EnvelopedData.  Support for AuthenticatedData and
       AuthEnvelopedData is OPTIONAL.

       In order to encourage interoperability, implementations SHOULD use
       the elliptic curve domain parameters specified by [PKI-ALG].

       Implementations that support SignedData with ECDSA:

          - MUST support ECDSA with SHA-256; and

          - MAY support ECDSA with SHA-1, ECDSA with SHA-224, ECDSA with
            SHA-384, and ECDSA with SHA-512; other digital signature
            algorithms MAY also be supported.

       When using ECDSA, to promote interoperability it is RECOMMENDED that
       the P-192, P-224, and P-256 curves be used with SHA-256; the P-384
       curve be used with SHA-384; and the P-521 curve be used with SHA-512.

       If EnvelopedData is supported, then ephemeral-static ECDH standard
       primitive MUST be supported.  Support for ephemeral-static ECDH co-
       factor is OPTIONAL, and support for 1-Pass ECMQV is also OPTIONAL.

       Implementations that support EnvelopedData with the ephemeral-static
       ECDH standard primitive:

          - MUST support the dhSinglePass-stdDH-sha256kdf-scheme key
            agreement algorithm, the id-aes128-wrap key wrap algorithm, and
            the id-aes128-cbc content encryption algorithm; and

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          - MAY support the dhSinglePass-stdDH-sha1kdf-scheme, dhSinglePass-
            stdDH-sha224kdf-scheme, dhSinglePass-stdDH-sha384kdf-scheme, and
            dhSinglePass-stdDH-sha512kdf-scheme key agreement algorithms;
            the id-alg-CMS3DESwrap, id-aes192-wrap, and id-aes256-wrap key
            wrap algorithms; and the des-ede3-cbc, id-aes192-cbc, and id-
            aes256-cbc content encryption algorithms; other algorithms MAY
            also be supported.

       Implementations that support EnvelopedData with the ephemeral-static
       ECDH cofactor primitive:

          - MUST support the dhSinglePass-cofactorDH-sha256kdf-scheme key
            agreement algorithm, the id-aes128-wrap key wrap algorithm, and
            the id-aes128-cbc content encryption algorithm; and

          - MAY support the dhSinglePass-cofactorDH-sha1kdf-scheme,
            dhSinglePass-cofactorDH-sha224kdf-scheme, dhSinglePass-
            cofactorDH-sha384kdf-scheme, and dhSinglePass-cofactorDH-
            sha512kdf-scheme key agreement; the id-alg-CMS3DESwrap, id-
            aes192-wrap, and id-aes256-wrap key wrap algorithms; and the
            des-ede3-cbc, id-aes192-cbc, and id-aes256-cbc content
            encryption algorithms; other algorithms MAY also be supported.

       Implementations that support EnvelopedData with 1-Pass ECMQV:

          - MUST support the mqvSinglePass-sha256kdf-scheme key agreement
            algorithm, the id-aes128-wrap key wrap algorithm, and the id-
            aes128-cbc content encryption algorithm; and

          - MAY support the mqvSinglePass-sha1kdf-scheme, mqvSinglePass-
            sha224kdf-scheme, mqvSinglePass-sha384kdf-scheme, and
            mqvSinglePass-sha512kdf-scheme key agreement algorithms; the id-
            alg-CMS3DESwrap, id-aes192-wrap, and id-aes256-wrap key wrap
            algorithms; and the des-ede3-cbc, id-aes192-cbc, and id-
            aes256-cbc content encryption algorithms; other algorithms MAY
            also be supported.

       Implementations that support AuthenticatedData with 1-Pass ECMQV:

          - MUST support the mqvSinglePass-sha256kdf-scheme key agreement,
            the id-aes128-wrap key wrap, the id-sha256 message digest, and
            id-hmacWithSHA256 message authentication code algorithms; and

          - MAY support the mqvSinglePass-sha1kdf-scheme, mqvSinglePass-
            sha224kdf-scheme, mqvSinglePass-sha384kdf-scheme, mqvSinglePass-
            sha512kdf-scheme key agreement algorithms; the id-alg-
            CMS3DESwrap, id-aes192-wrap, and id-aes256-wrap key wrap
            algorithms; the id-sha1, id-sha224, id-sha384, and id-sha512,

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            message digest algorithms; and the hmac-SHA1, id-hmacWithSHA224,
            id-hmacWithSHA384, and id-hmacWithSHA512 message authentication
            code algorithms; other algorithms MAY also be supported.

       Implementations that support AuthEnvelopedData with 1-Pass ECMQV:

          - MUST support the mqvSinglePass-sha256kdf-scheme key agreement,
            the id-aes128-wrap key wrap, and the id-aes128-ccm
            authenticated-content encryption; and

          - MAY support the mqvSinglePass-sha1kdf-scheme, mqvSinglePass-
            sha224kdf-scheme, mqvSinglePass-sha384kdf-scheme, and
            mqvSinglePass-sha512kdf-scheme key agreement algorithms; the id-
            alg-CMS3DESwrap, id-aes192-wrap, and id-aes256-wrap key wrap
            algorithms; and the id-aes192-ccm, id-aes256-ccm, id-aes128-gcm,
            id-aes192-gcm, and id-aes256-ccm authenticated-content
            encryption algorithms; other algorithms MAY also be supported.

    9.  Security Considerations

       Cryptographic algorithms will be broken or weakened over time.
       Implementers and users need to check that the cryptographic
       algorithms listed in this document continue to provide the expected
       level of security.  The IETF from time to time may issue documents
       dealing with the current state of the art.

       Cryptographic algorithms rely on random numbers.  See [RANDOM] for
       guidance on generation of random numbers.

       Receiving agents that validate signatures and sending agents that
       encrypt messages need to be cautious of cryptographic processing
       usage when validating signatures and encrypting messages using keys
       larger than those mandated in this specification.  An attacker could
       send keys and/or certificates with keys that would result in
       excessive cryptographic processing, for example, keys larger than
       those mandated in this specification, which could swamp the
       processing element.  Agents that use such keys without first
       validating the certificate to a trust anchor are advised to have some
       sort of cryptographic resource management system to prevent such
       attacks.

       Using secret keys of an appropriate size is crucial to the security
       of a Diffie-Hellman exchange.  For elliptic curve groups, the size of
       the secret key must be equal to the size of n (the order of the group
       generated by the point g).  Using larger secret keys provides
       absolutely no additional security, and using smaller secret keys is
       likely to result in dramatically less security.  (See [SP800-56A] for
       more information on selecting secret keys.)

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       This specification is based on [CMS], [CMS-AES], [CMS-AESCG],
       [CMS-ALG], [CMS-AUTHENV], [CMS-DH], [CMS-SHA2], [FIPS180-3],
       [FIPS186-3], and [HMAC-SHA2], and the appropriate security
       considerations of those documents apply.

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

       When implementing EnvelopedData, AuthenticatedData, and
       AuthEnvelopedData, there are five algorithm-related choices that need
       to be made:

          1) What is the public key size?
          2) What is the KDF?
          3) What is the key wrap algorithm?
          4) What is the content encryption algorithm?
          5) What is the curve?

       Consideration must be given to the strength of the security provided
       by each of these choices.  Security algorithm strength is measured in
       bits, where bits is measured in equivalence to a symmetric cipher
       algorithm.  Thus, a strong symmetric cipher algorithm with a key of X
       bits is said to provide X bits of security.  For other algorithms,
       the key size is mapped to an equivalent symmetric cipher strength.
       It is recommended that the bits of security provided by each are
       roughly equivalent.  The following table provides comparable minimum
       bits of security [SP800-57] for the ECDH/ECMQV key sizes, KDFs, key
       wrapping algorithms, and content encryption algorithms.  It also
       lists curves [PKI-ALG] for the key sizes.

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       Minimum  | ECDH or  | Key        | Key      | Content     | Curves
       Bits of  | ECMQV    | Derivation | Wrap     | Encryption  |
       Security | Key Size | Function   | Alg.     | Alg.        |
       ---------+----------+------------+----------+-------------+----------
       80       | 160-223  | SHA-1      | 3DES     | 3DES CBC    | sect163k1
                |          | SHA-224    | AES-128  | AES-128 CBC | secp163r2
                |          | SHA-256    | AES-192  | AES-192 CBC | secp192r1
                |          | SHA-384    | AES-256  | AES-256 CBC |
                |          | SHA-512    |          |             |
       ---------+----------+------------+----------+-------------+---------
       112      | 224-255  | SHA-1      | 3DES     | 3DES CBC    | secp224r1
                |          | SHA-224    | AES-128  | AES-128 CBC | sect233k1
                |          | SHA-256    | AES-192  | AES-192 CBC | sect233r1
                |          | SHA-384    | AES-256  | AES-256 CBC |
                |          | SHA-512    |          |             |
       ---------+----------+------------+----------+-------------+---------
       128      | 256-383  | SHA-1      | AES-128  | AES-128 CBC | secp256r1
                |          | SHA-224    | AES-192  | AES-192 CBC | sect283k1
                |          | SHA-256    | AES-256  | AES-256 CBC | sect283r1
                |          | SHA-384    |          |             |
                |          | SHA-512    |          |             |
       ---------+----------+------------+----------+-------------+---------
       192      | 384-511  | SHA-224    | AES-192  | AES-192 CBC | secp384r1
                |          | SHA-256    | AES-256  | AES-256 CBC | sect409k1
                |          | SHA-384    |          |             | sect409r1
                |          | SHA-512    |          |             |
       ---------+----------+------------+----------+-------------+---------
       256      | 512+     | SHA-256    | AES-256  | AES-256 CBC | secp521r1
                |          | SHA-384    |          |             | sect571k1
                |          | SHA-512    |          |             | sect571r1
       ---------+----------+------------+----------+-------------+---------

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       To promote interoperability, the following choices are RECOMMENDED:

       Minimum  | ECDH or  | Key        | Key      | Content     | Curve
       Bits of  | ECMQV    | Derivation | Wrap     | Encryption  |
       Security | Key Size | Function   | Alg.     | Alg.        |
       ---------+----------+------------+----------+-------------+----------
       80       | 192      | SHA-256    | 3DES     | 3DES CBC    | secp192r1
       ---------+----------+------------+----------+-------------+----------
       112      | 224      | SHA-256    | 3DES     | 3DES CBC    | secp224r1
       ---------+----------+------------+----------+-------------+----------
       128      | 256      | SHA-256    | AES-128  | AES-128 CBC | secp256r1
       ---------+----------+------------+----------+-------------+----------
       192      | 384      | SHA-384    | AES-256  | AES-256 CBC | secp384r1
       ---------+----------+------------+----------+-------------+----------
       256      | 512+     | SHA-512    | AES-256  | AES-256 CBC | secp521r1
       ---------+----------+------------+----------+-------------+----------

       When implementing SignedData, there are three algorithm-related
       choices that need to be made:

          1) What is the public key size?
          2) What is the hash algorithm?
          3) What is the curve?

       Consideration must be given to the bits of security provided by each
       of these choices.  Security is measured in bits, where a strong
       symmetric cipher with a key of X bits is said to provide X bits of
       security.  It is recommended that the bits of security provided by
       each choice are roughly equivalent.  The following table provides
       comparable minimum bits of security [SP800-57] for the ECDSA key
       sizes and message digest algorithms.  It also lists curves [PKI-ALG]
       for the key sizes.

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       Minimum  | ECDSA    | Message   | Curve
       Bits of  | Key Size | Digest    |
       Security |          | Algorithm |
       ---------+----------+-----------+-----------
       80       | 160-223  | SHA-1     | sect163k1
                |          | SHA-224   | secp163r2
                |          | SHA-256   | secp192r1
                |          | SHA-384   |
                |          | SHA-512   |
       ---------+----------+-----------+-----------
       112      | 224-255  | SHA-224   | secp224r1
                |          | SHA-256   | sect233k1
                |          | SHA-384   | sect233r1
                |          | SHA-512   |
       ---------+----------+-----------+-----------
       128      | 256-383  | SHA-256   | secp256r1
                |          | SHA-384   | sect283k1
                |          | SHA-512   | sect283r1
       ---------+----------+-----------+-----------
       192      | 384-511  | SHA-384   | secp384r1
                |          | SHA-512   | sect409k1
                |          |           | sect409r1
       ---------+----------+-----------+-----------
       256      | 512+     | SHA-512   | secp521r1
                |          |           | sect571k1
                |          |           | sect571r1
       ---------+----------+-----------+-----------

       To promote interoperability, the following choices are RECOMMENDED:

       Minimum  | ECDSA    | Message   | Curve
       Bits of  | Key Size | Digest    |
       Security |          | Algorithm |
       ---------+----------+-----------+-----------
       80       | 192      | SHA-256   | sect192r1
       ---------+----------+-----------+-----------
       112      | 224      | SHA-256   | secp224r1
       ---------+----------+-----------+-----------
       128      | 256      | SHA-256   | secp256r1
       ---------+----------+-----------+-----------
       192      | 384      | SHA-384   | secp384r1
       ---------+----------+-----------+-----------
       256      | 512+     | SHA-512   | secp521r1
       ---------+----------+-----------+-----------

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    10.  IANA Considerations

       This document makes extensive use of object identifiers to register
       originator public key types and algorithms.  The algorithm object
       identifiers are registered in the ANSI X9.62, ANSI X9.63, NIST, RSA,
       and SECG arcs.  Additionally, object identifiers are used to identify
       the ASN.1 modules found in Appendix A (there are two).  These are
       defined by the SMIME WG Registrar in an arc delegated by RSA to the
       SMIME Working Group: iso(1) member-body(2) us(840) rsadsi(113549)
       pkcs(1) pkcs-9(9) smime(16) modules(0).  No action by IANA is
       necessary for this document or any anticipated updates.

    11.  References

    11.1.  Normative References

       [CMS]          Housley, R., "Cryptographic Message Syntax (CMS)", RFC
                      5652, September 2009.

       [CMS-AES]      Schaad, J., "Use of the Advanced Encryption Standard
                      (AES) Encryption Algorithm in Cryptographic Message
                      Syntax (CMS)", RFC 3565, July 2003.

       [CMS-AESCG]    Housley, R., "Using AES-CCM and AES-GCM Authenticated
                      Encryption in the Cryptographic Message Syntax (CMS)",
                      RFC 5084, December 2007.

       [CMS-ALG]      Housley, R., "Cryptographic Message Syntax (CMS)
                      Algorithms", RFC 3370, August 2002.

       [CMS-AUTHENV]  Housley, R., "Cryptographic Message Syntax (CMS)
                      Authenticated-Enveloped-Data Content Type", RFC 5083,
                      November 2007.

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

       [CMS-SHA2]     Turner, S., "Using SHA2 Algorithms with Cryptographic
                      Message Syntax", RFC 5754, January 2010.

       [FIPS180-3]    National Institute of Standards and Technology (NIST),
                      FIPS Publication 180-3: Secure Hash Standard, October
                      2008.

       [FIPS186-3]    National Institute of Standards and Technology (NIST),
                      FIPS Publication 186-3: Digital Signature Standard,
                      June 2009.

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       [HMAC-SHA2]    Nystrom, M., "Identifiers and Test Vectors for HMAC-
                      SHA-224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-
                      SHA-512", RFC 4231, December 2005.

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

       [MSG]          Ramsdell, B. and S. Turner, "Secure/Multipurpose
                      Internet Mail Extensions (S/MIME) Version 3.2 Message
                      Specification", RFC 5751, January 2010.

       [PKI]          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.

       [PKI-ALG]      Turner, S., Brown, D., Yiu, K., Housley, R., and T.
                      Polk, "Elliptic Curve Cryptography Subject Public Key
                      Information", RFC 5480, March 2009.

       [RANDOM]       Eastlake, D., 3rd, Schiller, J., and S. Crocker,
                      "Randomness Requirements for Security", BCP 106, RFC
                      4086, June 2005.

       [RSAOAEP]      Schaad, J., Kaliski, B., and R. Housley, "Additional
                      Algorithms and Identifiers for RSA Cryptography for
                      use in the Internet X.509 Public Key Infrastructure
                      Certificate and Certificate Revocation List (CRL)
                      Profile", RFC 4055, June 2005.

       [SEC1]         Standards for Efficient Cryptography Group, "SEC 1:
                      Elliptic Curve Cryptography", version 2.0, May 2009,
                      available from www.secg.org.

       [SP800-56A]    National Institute of Standards and Technology (NIST),
                      Special Publication 800-56A: Recommendation Pair-Wise
                      Key Establishment Schemes Using Discrete Logarithm
                      Cryptography (Revised), March 2007.

       [X.680]        ITU-T Recommendation X.680 (2002) | ISO/IEC
                      8824-1:2002. Information Technology - Abstract Syntax
                      Notation One.

    Turner & Brown                Informational                    [Page 34]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    11.2.  Informative References

       [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

       [CERTCAP]      Santesson, S., "X.509 Certificate Extension for
                      Secure/Multipurpose Internet Mail Extensions (S/MIME)
                      Capabilities", RFC 4262, December 2005.

       [CMS-ASN]      Hoffman, P. and J. Schaad, "New ASN.1 Modules for CMS
                      and S/MIME", Work in Progress, August 2009.

       [CMS-ECC]      Blake-Wilson, S., Brown, D., and P. Lambert, "Use of
                      Elliptic Curve Cryptography (ECC) Algorithms in
                      Cryptographic Message Syntax (CMS)", RFC 3278, April
                      2002.

       [CMS-KEA]      Pawling, J., "Use of the KEA and SKIPJACK Algorithms
                      in CMS", RFC 2876, July 2000.

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

       [PKI-ASN]      Hoffman, P. and J. Schaad, "New ASN.1 Modules for
                      PKIX", Work in Progress, August 2009.

       [SP800-57]     National Institute of Standards and Technology (NIST),
                      Special Publication 800-57: Recommendation for Key
                      Management - Part 1 (Revised), March 2007.

       [X.681]        ITU-T Recommendation X.681 (2002) | ISO/IEC
                      8824-2:2002. Information Technology - Abstract Syntax
                      Notation One: Information Object Specification.

       [X.682]        ITU-T Recommendation X.682 (2002) | ISO/IEC
                      8824-3:2002. Information Technology - Abstract Syntax
                      Notation One: Constraint Specification.

       [X.683]        ITU-T Recommendation X.683 (2002) | ISO/IEC
                      8824-4:2002. Information Technology - Abstract Syntax
                      Notation One: Parameterization of ASN.1
                      Specifications, 2002.

    Turner & Brown                Informational                    [Page 35]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       [X9.62]        X9.62-2005, "Public Key Cryptography for the Financial
                      Services Industry: The Elliptic Curve Digital
                      Signature Standard (ECDSA)", November, 2005.

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    Appendix A.   ASN.1 Modules

       Appendix A.1 provides the normative ASN.1 definitions for the
       structures described in this specification using ASN.1 as defined in
       [X.680] for compilers that support the 1988 ASN.1.

       Appendix A.2 provides informative ASN.1 definitions for the
       structures described in this specification using ASN.1 as defined in
       [X.680], [X.681], [X.682], and [X.683] for compilers that support the
       2002 ASN.1.  This appendix contains the same information as Appendix
       A.1 in a more recent (and precise) ASN.1 notation; however, Appendix
       A.1 takes precedence in case of conflict.

    A.1.  1988 ASN.1 Module

       CMSECCAlgs-2009-88
         { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
           smime(16) modules(0) id-mod-cms-ecc-alg-2009-88(45) }

       DEFINITIONS IMPLICIT TAGS ::=

       BEGIN

       -- EXPORTS ALL

       IMPORTS

       -- From [PKI]

       AlgorithmIdentifier
         FROM PKIX1Explicit88
           { iso(1) identified-organization(3) dod(6)
             internet(1) security(5) mechanisms(5) pkix(7) mod(0)
             pkix1-explicit(18) }

       -- From [RSAOAEP]

       id-sha224, id-sha256, id-sha384, id-sha512
         FROM PKIX1-PSS-OAEP-Algorithms
           { iso(1) identified-organization(3) dod(6) internet(1)
             security(5) mechanisms(5) pkix(7) id-mod(0)
             id-mod-pkix1-rsa-pkalgs(33) }

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       -- From [PKI-ALG]

       id-sha1, ecdsa-with-SHA1, ecdsa-with-SHA224,
       ecdsa-with-SHA256, ecdsa-with-SHA384, ecdsa-with-SHA512,
       id-ecPublicKey, ECDSA-Sig-Value, ECPoint, ECParameters
         FROM PKIX1Algorithms2008
           { iso(1) identified-organization(3) dod(6) internet(1)
             security(5) mechanisms(5) pkix(7) id-mod(0) 45 }

       -- From [CMS]

       OriginatorPublicKey, UserKeyingMaterial
         FROM CryptographicMessageSyntax2004
           { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
             smime(16) modules(0) cms-2004(24) }

       -- From [CMS-ALG]

       hMAC-SHA1, des-ede3-cbc, id-alg-CMS3DESwrap, CBCParameter
         FROM CryptographicMessageSyntaxAlgorithms
           { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
             smime(16) modules(0) cmsalg-2001(16) }

       -- From [CMS-AES]

       id-aes128-CBC, id-aes192-CBC, id-aes256-CBC, AES-IV,
       id-aes128-wrap, id-aes192-wrap, id-aes256-wrap
         FROM CMSAesRsaesOaep
           { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
             smime(16) modules(0) id-mod-cms-aes(19) }

       -- From [CMS-AESCG]

       id-aes128-CCM, id-aes192-CCM, id-aes256-CCM, CCMParameters
       id-aes128-GCM, id-aes192-GCM, id-aes256-GCM, GCMParameters
         FROM CMS-AES-CCM-and-AES-GCM
           { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
             smime(16) modules(0) id-mod-cms-aes(32) }

       ;

       --
       -- Message Digest Algorithms: Imported from [PKI-ALG] and [RSAOAEP]
       --

       -- id-sha1 Parameters are preferred absent
       -- id-sha224 Parameters are preferred absent
       -- id-sha256 Parameters are preferred absent

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       -- id-sha384 Parameters are preferred absent
       -- id-sha512 Parameters are preferred absent

       --
       -- Signature Algorithms: Imported from [PKI-ALG]
       --

       -- ecdsa-with-SHA1 Parameters are NULL
       -- ecdsa-with-SHA224 Parameters are absent
       -- ecdsa-with-SHA256 Parameters are absent
       -- ecdsa-with-SHA384 Parameters are absent
       -- ecdsa-with-SHA512 Parameters are absent

       -- ECDSA Signature Value
       -- Contents of SignatureValue OCTET STRING

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

       --
       -- Key Agreement Algorithms
       --

       x9-63-scheme OBJECT IDENTIFIER ::= {
         iso(1) identified-organization(3) tc68(133) country(16) x9(840)
         x9-63(63) schemes(0) }
       secg-scheme OBJECT IDENTIFIER ::= {
         iso(1) identified-organization(3) certicom(132) schemes(1) }

       --
       -- Diffie-Hellman Single Pass, Standard, with KDFs
       --

       -- Parameters are always present and indicate the key wrap algorithm
       -- with KeyWrapAlgorithm.

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

       dhSinglePass-stdDH-sha224kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 11 0 }

       dhSinglePass-stdDH-sha256kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 11 1 }

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       dhSinglePass-stdDH-sha384kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 11 2 }

       dhSinglePass-stdDH-sha512kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 11 3 }

       --
       -- Diffie-Hellman Single Pass, Cofactor, with KDFs
       --

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

       dhSinglePass-cofactorDH-sha224kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 14 0 }

       dhSinglePass-cofactorDH-sha256kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 14 1 }

       dhSinglePass-cofactorDH-sha384kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 14 2 }

       dhSinglePass-cofactorDH-sha512kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 14 3 }

       --
       -- MQV Single Pass, Cofactor, with KDFs
       --

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

       mqvSinglePass-sha224kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 15 0 }

       mqvSinglePass-sha256kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 15 1 }

       mqvSinglePass-sha384kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 15 2 }

       mqvSinglePass-sha512kdf-scheme OBJECT IDENTIFIER ::= {
         secg-scheme 15 3 }

       --
       -- Key Wrap Algorithms: Imported from [CMS-ALG] and [CMS-AES]
       --

    Turner & Brown                Informational                    [Page 40]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       KeyWrapAlgorithm ::= AlgorithmIdentifier

       -- id-alg-CMS3DESwrap Parameters are NULL
       -- id-aes128-wrap Parameters are absent
       -- id-aes192-wrap Parameters are absent
       -- id-aes256-wrap Parameters are absent

       --
       -- Content Encryption Algorithms: Imported from [CMS-ALG]
       -- and [CMS-AES]
       --

       -- des-ede3-cbc Parameters are CBCParameter
       -- id-aes128-CBC Parameters are AES-IV
       -- id-aes192-CBC Parameters are AES-IV
       -- id-aes256-CBC Parameters are AES-IV
       -- id-aes128-CCM Parameters are CCMParameters
       -- id-aes192-CCM Parameters are CCMParameters
       -- id-aes256-CCM Parameters are CCMParameters
       -- id-aes128-GCM Parameters are GCMParameters
       -- id-aes192-GCM Parameters are GCMParameters
       -- id-aes256-GCM Parameters are GCMParameters

       --
       -- Message Authentication Code Algorithms
       --

       -- hMAC-SHA1 Parameters are preferred absent

       -- HMAC with SHA-224, SHA-256, SHA_384, and SHA-512 Parameters are
       -- absent

       id-hmacWithSHA224 OBJECT IDENTIFIER ::= {
         iso(1) member-body(2) us(840) rsadsi(113549)
         digestAlgorithm(2) 8 }

       id-hmacWithSHA256 OBJECT IDENTIFIER ::= {
         iso(1) member-body(2) us(840) rsadsi(113549)
         digestAlgorithm(2) 9 }

       id-hmacWithSHA384 OBJECT IDENTIFIER ::= {
         iso(1) member-body(2) us(840) rsadsi(113549)
         digestAlgorithm(2) 10 }

       id-hmacWithSHA512 OBJECT IDENTIFIER ::= {
         iso(1) member-body(2) us(840) rsadsi(113549)
         digestAlgorithm(2) 11 }

    Turner & Brown                Informational                    [Page 41]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       --
       -- Originator Public Key Algorithms: Imported from [PKI-ALG]
       --

       -- id-ecPublicKey Parameters are absent, NULL, or ECParameters

       -- Format for both ephemeral and static public keys: Imported from
       -- [PKI-ALG]

       -- ECPoint ::= OCTET STRING

       -- ECParameters ::= CHOICE {
       --   namedCurve      OBJECT IDENTIFIER
       --   commented out in [PKI-ALG]  implicitCurve   NULL
       --   commented out in [PKI-ALG]  specifiedCurve  SpecifiedECDomain
       --   commented out in [PKI-ALG]  ...
       -- }
           -- implicitCurve and specifiedCurve MUST NOT be used in PKIX.
           -- Details for SpecifiedECDomain can be found in [X9.62].
           -- Any future additions to this CHOICE should be coordinated
           -- with ANSI X9.

       -- Format of KeyAgreeRecipientInfo ukm field when used with
       -- ECMQV

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

       -- 'SharedInfo' for input to KDF when using ECDH and ECMQV with
       -- EnvelopedData, AuthenticatedData, or AuthEnvelopedData

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

       --
       -- S/MIME Capabilities
       -- An identifier followed by type.
       --

    Turner & Brown                Informational                    [Page 42]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       --
       -- S/MIME Capabilities: Message Digest Algorithms
       --

       -- Found in [CMS-SHA2].

       --
       -- S/MIME Capabilities: Signature Algorithms
       --

       -- ecdsa-with-SHA1 Type NULL
       -- ecdsa-with-SHA224 Type absent
       -- ecdsa-with-SHA256 Type absent
       -- ecdsa-with-SHA384 Type absent
       -- ecdsa-with-SHA512 Type absent

       --
       -- S/MIME Capabilities: ECDH, Single Pass, Standard
       --

       -- dhSinglePass-stdDH-sha1kdf Type is the KeyWrapAlgorithm
       -- dhSinglePass-stdDH-sha224kdf Type is the KeyWrapAlgorithm
       -- dhSinglePass-stdDH-sha256kdf Type is the KeyWrapAlgorithm
       -- dhSinglePass-stdDH-sha384kdf Type is the KeyWrapAlgorithm
       -- dhSinglePass-stdDH-sha512kdf Type is the KeyWrapAlgorithm

       --
       -- S/MIME Capabilities: ECDH, Single Pass, Cofactor
       --

       -- dhSinglePass-cofactorDH-sha1kdf Type is the KeyWrapAlgorithm
       -- dhSinglePass-cofactorDH-sha224kdf Type is the KeyWrapAlgorithm
       -- dhSinglePass-cofactorDH-sha256kdf Type is the KeyWrapAlgorithm
       -- dhSinglePass-cofactorDH-sha384kdf Type is the KeyWrapAlgorithm
       -- dhSinglePass-cofactorDH-sha512kdf Type is the KeyWrapAlgorithm

       --
       -- S/MIME Capabilities: ECMQV, Single Pass, Standard
       --

       -- mqvSinglePass-sha1kdf Type is the KeyWrapAlgorithm
       -- mqvSinglePass-sha224kdf Type is the KeyWrapAlgorithm
       -- mqvSinglePass-sha256kdf Type is the KeyWrapAlgorithm
       -- mqvSinglePass-sha384kdf Type is the KeyWrapAlgorithm
       -- mqvSinglePass-sha512kdf Type is the KeyWrapAlgorithm

    Turner & Brown                Informational                    [Page 43]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       --
       -- S/MIME Capabilities: Message Authentication Code Algorithms
       --

       -- hMACSHA1 Type is preferred absent
       -- id-hmacWithSHA224 Type is absent
       -- if-hmacWithSHA256 Type is absent
       -- id-hmacWithSHA384 Type is absent
       -- id-hmacWithSHA512 Type is absent

       END

    Turner & Brown                Informational                    [Page 44]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    A.2.  2004 ASN.1 Module

    CMSECCAlgs-2009-02
      { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
        smime(16) modules(0) id-mod-cms-ecc-alg-2009-02(46) }

    DEFINITIONS IMPLICIT TAGS ::=

    BEGIN

    -- EXPORTS ALL

    IMPORTS

    -- From [PKI-ASN]

    mda-sha1, sa-ecdsaWithSHA1, sa-ecdsaWithSHA224, sa-ecdsaWithSHA256,
    sa-ecdsaWithSHA384, sa-ecdsaWithSHA512, id-ecPublicKey,
    ECDSA-Sig-Value, ECPoint, ECParameters
      FROM PKIXAlgs-2009
        { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) pkix(7) id-mod(0)
          id-mod-pkix1-algorithms2008-02(56) }

    -- From [PKI-ASN]

    mda-sha224, mda-sha256, mda-sha384, mda-sha512
      FROM PKIX1-PSS-OAEP-Algorithms-2009
        { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) pkix(7) id-mod(0)
          id-mod-pkix1-rsa-pkalgs-02(54) }

    -- FROM [CMS-ASN]

    KEY-WRAP, SIGNATURE-ALGORITHM, DIGEST-ALGORITHM, ALGORITHM,
    PUBLIC-KEY, MAC-ALGORITHM, CONTENT-ENCRYPTION, KEY-AGREE, SMIME-CAPS,
    AlgorithmIdentifier{}
      FROM AlgorithmInformation-2009
        { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) pkix(7) id-mod(0)
          id-mod-algorithmInformation-02(58) }

    -- From [CMS-ASN]

    OriginatorPublicKey, UserKeyingMaterial
      FROM CryptographicMessageSyntax-2009
        { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
          smime(16) modules(0) id-mod-cms-2004-02(41) }

    Turner & Brown                Informational                    [Page 45]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    -- From [CMS-ASN]

    maca-hMAC-SHA1, cea-3DES-cbc, kwa-3DESWrap, CBCParameter
      FROM CryptographicMessageSyntaxAlgorithms-2009
        { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
          smime(16) modules(0) id-mod-cmsalg-2001-02(37) }

    -- From [CMS-ASN]

    cea-aes128-cbc, cea-aes192-cbc, cea-aes256-cbc, kwa-aes128-wrap,
    kwa-aes192-wrap, kwa-aes256-wrap
      FROM CMSAesRsaesOaep-2009
        { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
          smime(16) modules(0) id-mod-cms-aes-02(38) }

    -- From [CMS-ASN]

    cea-aes128-CCM, cea-aes192-CCM, cea-aes256-CCM, cea-aes128-GCM,
    cea-aes192-GCM, cea-aes256-GCM
      FROM CMS-AES-CCM-and-AES-GCM-2009
        { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
          smime(16) modules(0) id-mod-cms-aes-ccm-gcm-02(44) }

    ;

    -- Constrains the SignedData digestAlgorithms field
    -- Constrains the SignedData SignerInfo digestAlgorithm field
    -- Constrains the AuthenticatedData digestAlgorithm field

    -- Message Digest Algorithms: Imported from [PKI-ASN]

    -- MessageDigestAlgs DIGEST-ALGORITHM ::= {
    --  mda-sha1   |
    --  mda-sha224 |
    --  mda-sha256 |
    --  mda-sha384 |
    --  mda-sha512,
    --  ...
    -- }

    -- Constrains the SignedData SignerInfo signatureAlgorithm field

    -- Signature Algorithms: Imported from [PKI-ASN]

    -- SignatureAlgs SIGNATURE-ALGORITHM ::= {
    --  sa-ecdsaWithSHA1   |
    --  sa-ecdsaWithSHA224 |
    --  sa-ecdsaWithSHA256 |

    Turner & Brown                Informational                    [Page 46]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    --  sa-ecdsaWithSHA384 |
    --  sa-ecdsaWithSHA512,
    --  ...
    -- }

    -- ECDSA Signature Value: Imported from [PKI-ALG]
    -- Contents of SignatureValue OCTET STRING

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

    --
    -- Key Agreement Algorithms
    --

    -- Constrains the EnvelopedData RecipientInfo KeyAgreeRecipientInfo
    --   keyEncryption Algorithm field
    -- Constrains the AuthenticatedData RecipientInfo
    --   KeyAgreeRecipientInfo keyEncryption Algorithm field
    -- Constrains the AuthEnvelopedData RecipientInfo
    --   KeyAgreeRecipientInfo keyEncryption Algorithm field

    -- DH variants are not used with AuthenticatedData or
    -- AuthEnvelopedData

    KeyAgreementAlgs KEY-AGREE ::= {
      kaa-dhSinglePass-stdDH-sha1kdf-scheme        |
      kaa-dhSinglePass-stdDH-sha224kdf-scheme      |
      kaa-dhSinglePass-stdDH-sha256kdf-scheme      |
      kaa-dhSinglePass-stdDH-sha384kdf-scheme      |
      kaa-dhSinglePass-stdDH-sha512kdf-scheme      |
      kaa-dhSinglePass-cofactorDH-sha1kdf-scheme   |
      kaa-dhSinglePass-cofactorDH-sha224kdf-scheme |
      kaa-dhSinglePass-cofactorDH-sha256kdf-scheme |
      kaa-dhSinglePass-cofactorDH-sha384kdf-scheme |
      kaa-dhSinglePass-cofactorDH-sha512kdf-scheme |
      kaa-mqvSinglePass-sha1kdf-scheme             |
      kaa-mqvSinglePass-sha224kdf-scheme           |
      kaa-mqvSinglePass-sha256kdf-scheme           |
      kaa-mqvSinglePass-sha384kdf-scheme           |
      kaa-mqvSinglePass-sha512kdf-scheme,
      ...
    }

    Turner & Brown                Informational                    [Page 47]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

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

    secg-scheme OBJECT IDENTIFIER ::= {
      iso(1) identified-organization(3) certicom(132) schemes(1) }

    --
    -- Diffie-Hellman Single Pass, Standard, with KDFs
    --

    -- Parameters are always present and indicate the Key Wrap Algorithm

    kaa-dhSinglePass-stdDH-sha1kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-stdDH-sha1kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-stdDH-sha1kdf-scheme
    }

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

    kaa-dhSinglePass-stdDH-sha224kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-stdDH-sha224kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-stdDH-sha224kdf-scheme
    }

    dhSinglePass-stdDH-sha224kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 11 0 }

    kaa-dhSinglePass-stdDH-sha256kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-stdDH-sha256kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-stdDH-sha256kdf-scheme
    }

    dhSinglePass-stdDH-sha256kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 11 1 }

    Turner & Brown                Informational                    [Page 48]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    kaa-dhSinglePass-stdDH-sha384kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-stdDH-sha384kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-stdDH-sha384kdf-scheme
    }

    dhSinglePass-stdDH-sha384kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 11 2 }

    kaa-dhSinglePass-stdDH-sha512kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-stdDH-sha512kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-stdDH-sha512kdf-scheme
    }

    dhSinglePass-stdDH-sha512kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 11 3 }

    --
    -- Diffie-Hellman Single Pass, Cofactor, with KDFs
    --

    kaa-dhSinglePass-cofactorDH-sha1kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-cofactorDH-sha1kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-cofactorDH-sha1kdf-scheme
    }

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

    kaa-dhSinglePass-cofactorDH-sha224kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-cofactorDH-sha224kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-cofactorDH-sha224kdf-scheme
    }

    dhSinglePass-cofactorDH-sha224kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 14 0 }

    Turner & Brown                Informational                    [Page 49]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    kaa-dhSinglePass-cofactorDH-sha256kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-cofactorDH-sha256kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-cofactorDH-sha256kdf-scheme
    }

    dhSinglePass-cofactorDH-sha256kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 14 1 }

    kaa-dhSinglePass-cofactorDH-sha384kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-cofactorDH-sha384kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-cofactorDH-sha384kdf-scheme
    }

    dhSinglePass-cofactorDH-sha384kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 14 2 }

    kaa-dhSinglePass-cofactorDH-sha512kdf-scheme KEY-AGREE ::= {
      IDENTIFIER dhSinglePass-cofactorDH-sha512kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-dhSinglePass-cofactorDH-sha512kdf-scheme
    }

    dhSinglePass-cofactorDH-sha512kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 14 3 }

    --
    -- MQV Single Pass, Cofactor, with KDFs
    --

    kaa-mqvSinglePass-sha1kdf-scheme KEY-AGREE ::= {
      IDENTIFIER mqvSinglePass-sha1kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-mqvSinglePass-sha1kdf-scheme
    }

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

    Turner & Brown                Informational                    [Page 50]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    kaa-mqvSinglePass-sha224kdf-scheme KEY-AGREE ::= {
      IDENTIFIER mqvSinglePass-sha224kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-mqvSinglePass-sha224kdf-scheme
    }

    mqvSinglePass-sha224kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 15 0 }

    kaa-mqvSinglePass-sha256kdf-scheme KEY-AGREE ::= {
      IDENTIFIER mqvSinglePass-sha256kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-mqvSinglePass-sha256kdf-scheme
    }

    mqvSinglePass-sha256kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 15 1 }

    kaa-mqvSinglePass-sha384kdf-scheme KEY-AGREE ::= {
      IDENTIFIER mqvSinglePass-sha384kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-mqvSinglePass-sha384kdf-scheme
    }

    mqvSinglePass-sha384kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 15 2 }

    kaa-mqvSinglePass-sha512kdf-scheme KEY-AGREE ::= {
      IDENTIFIER mqvSinglePass-sha512kdf-scheme
      PARAMS TYPE KeyWrapAlgorithm ARE required
      UKM -- TYPE unencoded data -- ARE preferredPresent
      SMIME-CAPS cap-kaa-mqvSinglePass-sha512kdf-scheme
    }

    mqvSinglePass-sha512kdf-scheme OBJECT IDENTIFIER ::= {
      secg-scheme 15 3 }

    --
    -- Key Wrap Algorithms: Imported from [CMS-ASN]
    --

    Turner & Brown                Informational                    [Page 51]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    KeyWrapAlgorithm ::= AlgorithmIdentifier { KEY-WRAP, { KeyWrapAlgs } }

    KeyWrapAlgs KEY-WRAP ::= {
      kwa-3DESWrap    |
      kwa-aes128-wrap |
      kwa-aes192-wrap |
      kwa-aes256-wrap,
      ...
    }

    --
    -- Content Encryption Algorithms: Imported from [CMS-ASN]
    --

    -- Constrains the EnvelopedData EncryptedContentInfo encryptedContent
    -- field and the AuthEnvelopedData EncryptedContentInfo
    -- contentEncryptionAlgorithm field

    -- ContentEncryptionAlgs CONTENT-ENCRYPTION ::= {
    --   cea-3DES-cbc |
    --   cea-aes128-cbc   |
    --   cea-aes192-cbc   |
    --   cea-aes256-cbc   |
    --   cea-aes128-ccm   |
    --   cea-aes192-ccm   |
    --   cea-aes256-ccm   |
    --   cea-aes128-gcm   |
    --   cea-aes192-gcm   |
    --   cea-aes256-gcm,
    --   ...
    --   }

    -- des-ede3-cbc and aes*-cbc are used with EnvelopedData and
    -- EncryptedData
    -- aes*-ccm are used with AuthEnvelopedData
    -- aes*-gcm are used with AuthEnvelopedData
    -- (where * is 128, 192, and 256)

    --
    -- Message Authentication Code Algorithms
    --

    -- Constrains the AuthenticatedData
    -- MessageAuthenticationCodeAlgorithm field
    --

    Turner & Brown                Informational                    [Page 52]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    MessageAuthAlgs MAC-ALGORITHM ::= {
    --  maca-hMAC-SHA1 |
      maca-hMAC-SHA224 |
      maca-hMAC-SHA256 |
      maca-hMAC-SHA384 |
      maca-hMAC-SHA512,
      ...
    }

    maca-hMAC-SHA224 MAC-ALGORITHM ::= {
      IDENTIFIER id-hmacWithSHA224
      PARAMS ARE absent
      IS-KEYED-MAC TRUE
      SMIME-CAPS cap-hMAC-SHA224
    }

    id-hmacWithSHA224 OBJECT IDENTIFIER ::= {
      iso(1) member-body(2) us(840) rsadsi(113549)
      digestAlgorithm(2) 8 }

    maca-hMAC-SHA256 MAC-ALGORITHM ::= {
      IDENTIFIER id-hmacWithSHA256
      PARAMS ARE absent
      IS-KEYED-MAC TRUE
      SMIME-CAPS cap-hMAC-SHA256
    }

    id-hmacWithSHA256 OBJECT IDENTIFIER ::= {
      iso(1) member-body(2) us(840) rsadsi(113549)
      digestAlgorithm(2) 9 }

    maca-hMAC-SHA384 MAC-ALGORITHM ::= {
      IDENTIFIER id-hmacWithSHA384
      PARAMS ARE absent
      IS-KEYED-MAC TRUE
      SMIME-CAPS cap-hMAC-SHA384
    }

    id-hmacWithSHA384 OBJECT IDENTIFIER ::= {
      iso(1) member-body(2) us(840) rsadsi(113549)
      digestAlgorithm(2) 10 }

    maca-hMAC-SHA512 MAC-ALGORITHM ::= {
      IDENTIFIER id-hmacWithSHA512
      PARAMS ARE absent
      IS-KEYED-MAC TRUE
      SMIME-CAPS cap-hMAC-SHA512
    }

    Turner & Brown                Informational                    [Page 53]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    id-hmacWithSHA512 OBJECT IDENTIFIER ::= {
      iso(1) member-body(2) us(840) rsadsi(113549)
      digestAlgorithm(2) 11 }

    --
    -- Originator Public Key Algorithms
    --

    -- Constraints on KeyAgreeRecipientInfo OriginatorIdentifierOrKey
    -- OriginatorPublicKey algorithm field

    OriginatorPKAlgorithms PUBLIC-KEY ::= {
      opka-ec,
      ...
    }

    opka-ec PUBLIC-KEY ::={
      IDENTIFIER id-ecPublicKey
      KEY ECPoint
      PARAMS TYPE CHOICE { n NULL, p ECParameters } ARE preferredAbsent
    }

    -- Format for both ephemeral and static public keys: Imported from
    -- [PKI-ALG]

    -- ECPoint ::= OCTET STRING

    -- ECParameters ::= CHOICE {
    --   namedCurve      CURVE.&id({NamedCurve})
    --   commented out in [PKI-ALG] implicitCurve   NULL
    --   commented out in [PKI-ALG] specifiedCurve  SpecifiedECDomain
    --   commented out in [PKI-ALG] ...
    -- }
      -- implicitCurve and specifiedCurve MUST NOT be used in PKIX.
      -- Details for SpecifiedECDomain can be found in [X9.62].
      -- Any future additions to this CHOICE should be coordinated
      -- with ANSI X.9.

    -- Format of KeyAgreeRecipientInfo ukm field when used with
    -- ECMQV

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

    Turner & Brown                Informational                    [Page 54]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    -- 'SharedInfo' for input to KDF when using ECDH and ECMQV with
    -- EnvelopedData, AuthenticatedData, or AuthEnvelopedData

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

    --
    -- S/MIME CAPS for algorithms in this document
    --

    Turner & Brown                Informational                    [Page 55]

    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    SMimeCAPS SMIME-CAPS ::= {
    --  mda-sha1.&smimeCaps                                   |
    --  mda-sha224.&smimeCaps                                 |
    --  mda-sha256.&smimeCaps                                 |
    --  mda-sha384.&smimeCaps                                 |
    --  mda-sha512.&smimeCaps                                 |
    --  sa-ecdsaWithSHA1.&smimeCaps                           |
    --  sa-ecdsaWithSHA224.&smimeCaps                         |
    --  sa-ecdsaWithSHA256.&smimeCaps                         |
    --  sa-ecdsaWithSHA384.&smimeCaps                         |
    --  sa-ecdsaWithSHA512.&smimeCaps                         |
      kaa-dhSinglePass-stdDH-sha1kdf-scheme.&smimeCaps        |
      kaa-dhSinglePass-stdDH-sha224kdf-scheme.&smimeCaps      |
      kaa-dhSinglePass-stdDH-sha256kdf-scheme.&smimeCaps      |
      kaa-dhSinglePass-stdDH-sha384kdf-scheme.&smimeCaps      |
      kaa-dhSinglePass-stdDH-sha512kdf-scheme.&smimeCaps      |
      kaa-dhSinglePass-cofactorDH-sha1kdf-scheme.&smimeCaps   |
      kaa-dhSinglePass-cofactorDH-sha224kdf-scheme.&smimeCaps |
      kaa-dhSinglePass-cofactorDH-sha256kdf-scheme.&smimeCaps |
      kaa-dhSinglePass-cofactorDH-sha384kdf-scheme.&smimeCaps |
      kaa-dhSinglePass-cofactorDH-sha512kdf-scheme.&smimeCaps |
      kaa-mqvSinglePass-sha1kdf-scheme.&smimeCaps             |
      kaa-mqvSinglePass-sha224kdf-scheme.&smimeCaps           |
      kaa-mqvSinglePass-sha256kdf-scheme.&smimeCaps           |
      kaa-mqvSinglePass-sha384kdf-scheme.&smimeCaps           |
      kaa-mqvSinglePass-sha512kdf-scheme.&smimeCaps           |
    --  kwa-3des.&smimeCaps                                   |
    --  kwa-aes128.&smimeCaps                                 |
    --  kwa-aes192.&smimeCaps                                 |
    --  kwa-aes256.&smimeCaps                                 |
    --  cea-3DES-cbc.&smimeCaps                               |
    --  cea-aes128-cbc.&smimeCaps                             |
    --  cea-aes192-cbc.&smimeCaps                             |
    --  cea-aes256-cbc.&smimeCaps                             |
    --  cea-aes128-ccm.&smimeCaps                             |
    --  cea-aes192-ccm.&smimeCaps                             |
    --  cea-aes256-ccm.&smimeCaps                             |
    --  cea-aes128-gcm.&smimeCaps                             |
    --  cea-aes192-gcm.&smimeCaps                             |
    --  cea-aes256-gcm.&smimeCaps                             |
    --  maca-hMAC-SHA1.&smimeCaps                             |
      maca-hMAC-SHA224.&smimeCaps                             |
      maca-hMAC-SHA256.&smimeCaps                             |
      maca-hMAC-SHA384.&smimeCaps                             |
      maca-hMAC-SHA512.&smimeCaps,
      ...
    }

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    cap-kaa-dhSinglePass-stdDH-sha1kdf-scheme SMIME-CAPS ::= {
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-stdDH-sha1kdf-scheme
    }

    cap-kaa-dhSinglePass-stdDH-sha224kdf-scheme SMIME-CAPS ::= {
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-stdDH-sha224kdf-scheme
    }

    cap-kaa-dhSinglePass-stdDH-sha256kdf-scheme SMIME-CAPS ::= {
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-stdDH-sha256kdf-scheme
    }

    cap-kaa-dhSinglePass-stdDH-sha384kdf-scheme SMIME-CAPS ::= {
       TYPE KeyWrapAlgorithm
       IDENTIFIED BY dhSinglePass-stdDH-sha384kdf-scheme
    }

    cap-kaa-dhSinglePass-stdDH-sha512kdf-scheme SMIME-CAPS ::= {
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-stdDH-sha512kdf-scheme
    }

    cap-kaa-dhSinglePass-cofactorDH-sha1kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-cofactorDH-sha1kdf-scheme
    }

    cap-kaa-dhSinglePass-cofactorDH-sha224kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-cofactorDH-sha224kdf-scheme
    }

    cap-kaa-dhSinglePass-cofactorDH-sha256kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-cofactorDH-sha256kdf-scheme
    }

    cap-kaa-dhSinglePass-cofactorDH-sha384kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-cofactorDH-sha384kdf-scheme
    }

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    cap-kaa-dhSinglePass-cofactorDH-sha512kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY dhSinglePass-cofactorDH-sha512kdf-scheme
    }

    cap-kaa-mqvSinglePass-sha1kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY mqvSinglePass-sha1kdf-scheme
    }

    cap-kaa-mqvSinglePass-sha224kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY mqvSinglePass-sha224kdf-scheme
    }

    cap-kaa-mqvSinglePass-sha256kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY mqvSinglePass-sha256kdf-scheme
    }

    cap-kaa-mqvSinglePass-sha384kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY mqvSinglePass-sha384kdf-scheme
    }

    cap-kaa-mqvSinglePass-sha512kdf-scheme SMIME-CAPS ::={
      TYPE KeyWrapAlgorithm
      IDENTIFIED BY mqvSinglePass-sha512kdf-scheme
    }

    cap-hMAC-SHA224 SMIME-CAPS ::={ IDENTIFIED BY id-hmacWithSHA224 }

    cap-hMAC-SHA256 SMIME-CAPS ::={ IDENTIFIED BY id-hmacWithSHA256 }

    cap-hMAC-SHA384 SMIME-CAPS ::={ IDENTIFIED BY id-hmacWithSHA384 }

    cap-hMAC-SHA512 SMIME-CAPS ::={ IDENTIFIED BY id-hmacWithSHA512 }

    END

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    Appendix B.  Changes since RFC 3278

       The following summarizes the changes:

       - Abstract: The basis of the document was changed to refer to NIST
         FIPS 186-3 and SP800-56A.  However, to maintain backwards
         compatibility the Key Derivation Function from ANSI/SEC1 is
         retained.

       - Section 1: A bullet was added to address AuthEnvelopedData.

       - Section 2.1: A sentence was added to indicate FIPS180-3 is used
         with ECDSA.  Replaced reference to ANSI X9.62 with FIPS186-3.

       - Section 2.1.1: The permitted digest algorithms were expanded from
         SHA-1 to SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512.

       - Section 2.1.2 and 2.1.3: The bullet addressing integer "e" was
         deleted.

       - Section 3: Added explanation of why static-static ECDH is not
         included.

       - Section 3.1: The reference for DH was changed from RFC 3852 to RFC
         3370.  Provided text to indicate fields of EnvelopedData are as in
         CMS.

       - Section 3.1.1: The text was updated to include description of all
         KeyAgreeRecipientInfo fields.  Parameters for id-ecPublicKey field
         changed from NULL to absent or ECParameter.  Additional information
         about ukm was added.

       - Section 3.2: The sentence describing the advantages of 1-Pass ECMQV
         was rewritten.

       - Section 3.2.1: The text was updated to include description of all
         fields.  Parameters for id-ecPublicKey field changed from NULL to
         absent or ECParameters.

       - Sections 3.2.2 and 4.1.2: The re-use of ephemeral keys paragraph
         was reworded.

       - Section 4.1:  The sentences describing the advantages of 1-Pass
         ECMQV was moved to Section 4.

       - Section 4.1.2: The note about the attack was moved to Section 4.

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

       - Section 4.2: This section was added to address AuthEnvelopedData
         with ECMQV.

       - Section 5: This section was moved to Section 8.  The 1st paragraph
         was modified to recommend both SignedData and EnvelopedData.  The
         requirements were updated for hash algorithms and recommendations
         for matching curves and hash algorithms.  Also, the requirements
         were expanded to indicate which ECDH and ECMQV variants, key wrap
         algorithms, and content encryption algorithms are required for each
         of the content types used in this document.  The permitted digest
         algorithms used in KDFs were expanded from SHA-1 to SHA-1, SHA-224,
         SHA-256, SHA-384, and SHA-512.

       - Section 6 (formerly 7): This section was updated to allow for
         SMIMECapabilities to be present in certificates.  The S/MIME
         capabilities for ECDSA with SHA-224, SHA-256, SHA-384, and SHA-512
         were added to the list of S/MIME Capabilities.  Also, updated to
         include S/MIME capabilities for ECDH and ECMQV using the SHA-224,
         SHA-256, SHA-384, and SHA-512 algorithms as the KDF.

       - Section 7.1 (formerly 8.1): Added sub-sections for digest,
         signature, originator public key, key agreement, content
         encryption, key wrap, and message authentication code algorithms.
         Pointed to algorithms and parameters in appropriate documents for:
         SHA-224, SHA-256, SHA-384, and SHA-512 as well as SHA-224, SHA-256,
         SHA-384, and SHA-512 with ECDSA.  Also, added algorithm identifiers
         for ECDH std, ECDH cofactor, and ECMQV with SHA-224, SHA-256,
         SHA-384, and SHA-512 algorithms as the KDF.  Changed id-ecPublicKey
         parameters to be absent, NULL, or ECParameters, and if present the
         originator's ECParameters must match the recipient's ECParameters.

       - Section 7.2 (formerly 8.2): Updated to include AuthEnvelopedData.
         Also, added text to address support requirement for compressed,
         uncompressed, and hybrid keys; changed pointers from ANSI X9.61 to
         PKIX (where ECDSA-Sig-Value is imported); changed pointers from
         SECG to NIST specs; and updated example of suppPubInfo to be
         AES-256.  keyInfo's parameters changed from NULL to any associated
         parameters (AES wraps have absent parameters).

       - Section 9: Replaced text, which was a summary paragraph, with an
         updated security considerations section.  Paragraph referring to
         definitions of SHA-224, SHA-256, SHA-384, and SHA-512 is deleted.

       - Updated references.

       - Added ASN.1 modules.

       - Updated acknowledgements section.

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    RFC 5753              Use of ECC Algorithms in CMS          January 2010

    Acknowledgements

       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.

       Many thanks go out to the other authors of RFC 3278: Simon Blake-
       Wilson and Paul Lambert.  Without RFC 3278, this version wouldn't
       exist.

       The authors also wish to thank Alfred Hoenes, Jonathan Herzog, Paul
       Hoffman, Russ Housley, and Jim Schaad for their valuable input.

    Authors' Addresses

       Sean Turner
       IECA, Inc.
       3057 Nutley Street, Suite 106
       Fairfax, VA 22031
       USA

       EMail: turners@ieca.com

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

       EMail: dbrown@certicom.com

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