Using the Elliptic Curve Cryptography (ECC) Brainpool Curves for the Internet Key Exchange Protocol Version 2 (IKEv2)
RFC 6954

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Internet Engineering Task Force (IETF)                         J. Merkle
Request for Comments: 6954                     secunet Security Networks
Category: Informational                                       M. Lochter
ISSN: 2070-1721                                                      BSI
                                                               July 2013

      Using the Elliptic Curve Cryptography (ECC) Brainpool Curves
        for the Internet Key Exchange Protocol Version 2 (IKEv2)

Abstract

   This document specifies use of the Elliptic Curve Cryptography (ECC)
   Brainpool elliptic curve groups for key exchange in the Internet Key
   Exchange Protocol version 2 (IKEv2).

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/rfc6954.

Copyright Notice

   Copyright (c) 2013 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.

Merkle & Lochter              Informational                     [Page 1]
RFC 6954         Brainpool Curves for IKEv2 Key Exchange       July 2013

Table of Contents

   1. Introduction ....................................................2
      1.1. Requirements Language ......................................2
   2. IKEv2 Key Exchange Using the ECC Brainpool Curves ...............3
      2.1. Diffie-Hellman Group Transform IDs .........................3
      2.2. Using the Twisted Brainpool Curves Internally ..............3
      2.3. Key Exchange Payload and Shared Secret .....................3
   3. Security Considerations .........................................4
   4. IANA Considerations .............................................5
   5. References ......................................................5
      5.1. Normative References .......................................5
      5.2. Informative References .....................................6
   Appendix A. Test Vectors ...........................................8
     A.1. 224-Bit Curve ...............................................8
     A.2. 256-Bit Curve ...............................................9
     A.3. 384-Bit Curve ...............................................9
     A.4. 512-Bit Curve ..............................................10

1.  Introduction

   [RFC5639] specified a new set of elliptic curve groups over finite
   prime fields for use in cryptographic applications.  These groups,
   denoted as ECC Brainpool curves, were generated in a verifiably
   pseudo-random way and comply with the security requirements of
   relevant standards from ISO [ISO1] [ISO2], ANSI [ANSI1], NIST [FIPS],
   and the Standards for Efficient Cryptography Group [SEC2].

   While the ASN.1 object identifiers defined in RFC 5639 allow usage of
   the ECC Brainpool curves in certificates and certificate revocation
   lists, their utilization for key exchange in IKEv2 [RFC5996] requires
   the definition and assignment of additional Diffie-Hellman Group
   Transform IDs in the respective IANA registry.  This document
   specifies transform IDs for four curves from RFC 5639, as well as the
   encoding of the key exchange payload and derivation of the shared
   secret when using one of these curves.

1.1.  Requirements Language

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

Merkle & Lochter              Informational                     [Page 2]
RFC 6954         Brainpool Curves for IKEv2 Key Exchange       July 2013

2.  IKEv2 Key Exchange Using the ECC Brainpool Curves

2.1.  Diffie-Hellman Group Transform IDs

   In order to use the ECC Brainpool curves for key exchange within
   IKEv2, the Diffie-Hellman Group Transform IDs (Transform Type 4)