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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/rfc6161.

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 [RFC6032].  Specifically, it
 includes conventions necessary to implement the following CMS content
 types: EnvelopedData [RFC5652] and SignedData [RFC5652].  This
 document amends [RFC6033].  Familiarity with [RFC6033] and [RFC5753]
 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
 [RFC2119].

2. EnvelopedData

 When key agreement is used, standard (as opposed to cofactor) ECDH
 [RFC6090][RFC5753] MAY be supported.

3. SignedData

 If an implementation encapsulates EncryptedKeyPackage with SignedData
 [RFC5652], then it MAY support the signature scheme ECDSA
 [RFC6090][RFC5753].

4. Public Key Sizes

 The easiest way to implement SignedData and EnvelopedData is with
 public key certificates [RFC5280][RFC5480].  If an implementation
 supports ECDSA or ECDH, then it MUST support keys on the P-256 curve.

5. Security Considerations

 The security considerations from [RFC5280], [RFC5480], [RFC5652],
 [RFC5753], [RFC6033], and [RFC6090] apply.

6. Normative References

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

Turner Standards Track [Page 2] RFC 6161 EC Algorithms for CMS Encrypted Key Packages April 2011

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

 [RFC5480]  Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
            "Elliptic Curve Cryptography Subject Public Key
            Information", RFC 5480, March 2009.

 [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
            RFC 5652, September 2009.

 [RFC5753]  Turner, S. and D. Brown, "Use of Elliptic Curve
            Cryptography (ECC) Algorithms in Cryptographic Message
            Syntax (CMS)", RFC 5753, January 2010.

 [RFC6032]  Turner, S. and R. Housley, "Cryptographic Message Syntax
            (CMS) Encrypted Key Package Content Type", RFC 6032,
            December 2010.

 [RFC6033]  Turner, S., "Algorithms for Cryptographic Message Syntax
            (CMS) Encrypted Key Package Content Type", RFC 6033,
            December 2010.

 [RFC6090]  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]