Using Advanced Encryption Standard Counter Mode (AES-CTR) with the Internet Key Exchange version 02 (IKEv2) Protocol
RFC 5930

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Internet Engineering Task Force (IETF)                           S. Shen
Request for Comments: 5930                                        Huawei
Category: Informational                                           Y. Mao
ISSN: 2070-1721                             Hangzhou H3C Tech. Co., Ltd.
                                                             NSS. Murthy
                                                 Freescale Semiconductor
                                                               July 2010

       Using Advanced Encryption Standard Counter Mode (AES-CTR)
       with the Internet Key Exchange version 02 (IKEv2) Protocol

Abstract

   This document describes the usage of Advanced Encryption Standard
   Counter Mode (AES-CTR), with an explicit Initialization Vector, by
   the Internet Key Exchange version 2 (IKEv2) protocol, for encrypting
   the IKEv2 exchanges that follow the IKE_SA_INIT exchange.

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/rfc5930.

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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
   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.

Table of Contents

   1. Introduction ....................................................2
      1.1. Conventions Used in This Document ..........................3
   2. IKEv2 Encrypted Payload .........................................3
   3. IKEv2 Conventions ...............................................4
   4. Security Considerations .........................................4
   5. IANA Considerations .............................................4
   6. Acknowledgments .................................................4
   7. References ......................................................5
      7.1. Normative References .......................................5
      7.2. Informative References .....................................5

1.  Introduction

   The Internet Key Exchange version 2 (IKEv2) protocol [RFC4306] is a
   component of IPsec used for performing mutual authentication and
   establishing and maintaining security associations (SAs).  [RFC4307]
   defines the set of algorithms that are mandatory to implement as part
   of IKEv2, as well as algorithms that should be implemented because
   they may be promoted to mandatory at some future time.  [RFC4307]
   requires that an implementation "SHOULD" support Advanced Encryption
   Standard [AES] Counter Mode [MODES] (AES-CTR) as a Transform Type 1
   algorithm (encryption).

   Although [RFC4307] specifies that the AES-CTR encryption algorithm
   feature SHOULD be supported by IKEv2, no existing document specifies
   how IKEv2 can support the feature.  This document provides the
   specification and usage of AES-CTR Counter Mode by IKEv2.

   Implementers need to carefully consider the use of AES-CTR over the
   mandatory-to-implement algorithms in [RFC4307], because the
   performance improvements of AES-CTR are minimal in the context of

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RFC 5930                    AES-CTR for IKEv2                  July 2010

   IKEv2.  Furthermore, these performance improvements may be offset by
   the Counter Mode specific risk of a minor, hard-to-detect
   implementation issue resulting in total security failure.

1.1.  Conventions Used in This Document

   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].

2.  IKEv2 Encrypted Payload

   Section 3.14 of IKEv2 [RFC4306] explains the IKEv2 Encrypted Payload.