Internet Engineering Task Force (IETF)                         S. Turner
Request for Comments: 6161                                          IECA
Updates: 6033                                                 April 2011
Category: Standards Track
ISSN: 2070-1721

    Elliptic Curve Algorithms for Cryptographic Message Syntax (CMS)
                   Encrypted Key Package Content Type

Abstract

   This document describes the conventions for using several Elliptic
   Curve cryptographic algorithms with the Cryptographic Message Syntax
   (CMS) encrypted key package content type.  Specifically, it includes
   conventions necessary to implement Elliptic Curve Diffie-Hellman
   (ECDH) with EnvelopedData and Elliptic Curve Digital Signature
   Algorithm (ECDSA) with SignedData.  This document extends RFC 6033.

Status of This Memo

   This is an Internet Standards Track document.

   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).  Further information on
   Internet Standards is available in 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/RFC 6161.

Copyright Notice

   Copyright (c) 2011 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
   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.

Turner                       Standards Track                    [Page 1]

RFC 6161      EC Algorithms for CMS Encrypted Key Packages    April 2011

1.  Introduction

   This document describes the conventions for using Elliptic Curve
   cryptographic algorithms with the Cryptographic Message Syntax (CMS)
   encrypted key package content type [RFC 6032].  Specifically, it
   includes conventions necessary to implement the following CMS content
   types: EnvelopedData [RFC 5652] and SignedData [RFC 5652].  This
   document amends [RFC 6033].  Familiarity with [RFC 6033] and [RFC 5753]
   is assumed.

   This document does not define any new algorithms; instead, it refers
   to previously defined algorithms.

1.1  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC 2119].

2.  EnvelopedData

   When key agreement is used, standard (as opposed to cofactor) ECDH
   [RFC 6090][RFC 5753] MAY be supported.

3.  SignedData

   If an implementation encapsulates EncryptedKeyPackage with SignedData
   [RFC 5652], then it MAY support the signature scheme ECDSA
   [RFC 6090][RFC 5753].

4.  Public Key Sizes

   The easiest way to implement SignedData and EnvelopedData is with
   public key certificates [RFC 5280][RFC 5480].  If an implementation
   supports ECDSA or ECDH, then it MUST support keys on the P-256 curve.

5.  Security Considerations

   The security considerations from [RFC 5280], [RFC 5480], [RFC 5652],
   [RFC 5753], [RFC 6033], and [RFC 6090] apply.

6.  Normative References

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

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RFC 6161      EC Algorithms for CMS Encrypted Key Packages    April 2011

   [RFC 5280]  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.

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

   [RFC 5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, September 2009.

   [RFC 5753]  Turner, S. and D. Brown, "Use of Elliptic Curve
              Cryptography (ECC) Algorithms in Cryptographic Message
              Syntax (CMS)", RFC 5753, January 2010.

   [RFC 6032]  Turner, S. and R. Housley, "Cryptographic Message Syntax
              (CMS) Encrypted Key Package Content Type", RFC 6032,
              December 2010.

   [RFC 6033]  Turner, S., "Algorithms for Cryptographic Message Syntax
              (CMS) Encrypted Key Package Content Type", RFC 6033,
              December 2010.

   [RFC 6090]  McGrew, D., Igoe, K., and M. Salter, "Fundamental Elliptic
              Curve Cryptography Algorithms", RFC 6090, February 2011.

Author's Address

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

   EMail: turners@ieca.com

Turner                       Standards Track                    [Page 3]