AES-CCM Elliptic Curve Cryptography (ECC) Cipher Suites for TLS
RFC 7251

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Internet Engineering Task Force (IETF)                         D. McGrew
Request for Comments: 7251                                 Cisco Systems
Category: Informational                                        D. Bailey
ISSN: 2070-1721                                   Ruhr-University Bochum
                                                             M. Campagna
                                                                R. Dugal
                                                          Certicom Corp.
                                                               June 2014

    AES-CCM Elliptic Curve Cryptography (ECC) Cipher Suites for TLS

Abstract

   This memo describes the use of the Advanced Encryption Standard (AES)
   in the Counter and CBC-MAC Mode (CCM) of operation within Transport
   Layer Security (TLS) to provide confidentiality and data-origin
   authentication.  The AES-CCM algorithm is amenable to compact
   implementations, making it suitable for constrained environments,
   while at the same time providing a high level of security.  The
   cipher suites defined in this document use Elliptic Curve
   Cryptography (ECC) and are advantageous in networks with limited
   bandwidth.

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/rfc7251.

McGrew, et al.                Informational                     [Page 1]
RFC 7251                     AES-CCM ECC TLS                   June 2014

Copyright Notice

   Copyright (c) 2014 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Conventions Used in This Document . . . . . . . . . . . .   3
   2.  ECC-Based AES-CCM Cipher Suites . . . . . . . . . . . . . . .   3
     2.1.  AEAD Algorithms . . . . . . . . . . . . . . . . . . . . .   5
     2.2.  Requirements on Curves and Hashes . . . . . . . . . . . .   5
   3.  TLS Versions  . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
     5.1.  Perfect Forward Secrecy . . . . . . . . . . . . . . . . .   6
     5.2.  Counter Reuse . . . . . . . . . . . . . . . . . . . . . .   6
     5.3.  Hardware Security Modules . . . . . . . . . . . . . . . .   6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Appendix A.  Recommended Curves and Algorithms  . . . . . . . . .   9

McGrew, et al.                Informational                     [Page 2]
RFC 7251                     AES-CCM ECC TLS                   June 2014

1.  Introduction

   This document describes the use of Advanced Encryption Standard (AES)
   [AES] in Counter with CBC-MAC Mode (CCM) [CCM] in several TLS cipher
   suites.  AES-CCM provides both authentication and confidentiality
   (encryption and decryption) and uses as its only primitive the AES
   encrypt block cipher operation.  This makes it amenable to compact
   implementations, which are advantageous in constrained environments.
   Of course, adoption outside of constrained environments is necessary
   to enable interoperability, such as that between web clients and
   embedded servers, or between embedded clients and web servers.  The
   use of AES-CCM has been specified for the IPsec Encapsulating
   Security Payload (ESP) [RFC4309] and 802.15.4 wireless networks
   [IEEE802154].

   Authenticated encryption, in addition to providing confidentiality