AES-GCM-SIV: Nonce Misuse-Resistant Authenticated Encryption
draft-irtf-cfrg-gcmsiv-09

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CFRG                                                           S. Gueron
Internet-Draft               University of Haifa and Amazon Web Services
Intended status: Informational                                A. Langley
Expires: May 23, 2019                                         Google LLC
                                                              Y. Lindell
                                                     Bar Ilan University
                                                       November 19, 2018

      AES-GCM-SIV: Nonce Misuse-Resistant Authenticated Encryption
                       draft-irtf-cfrg-gcmsiv-09

Abstract

   This memo specifies two authenticated encryption algorithms that are
   nonce misuse-resistant - that is that they do not fail
   catastrophically if a nonce is repeated.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on May 23, 2019.

Copyright Notice

   Copyright (c) 2018 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
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   include Simplified BSD License text as described in Section 4.e of

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  POLYVAL . . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Encryption  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Decryption  . . . . . . . . . . . . . . . . . . . . . . . . .   7
   6.  AEADs . . . . . . . . . . . . . . . . . . . . . . . . . . . .  10
   7.  Field operation examples  . . . . . . . . . . . . . . . . . .  10
   8.  Worked example  . . . . . . . . . . . . . . . . . . . . . . .  10
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   11. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  15
     12.2.  Informative References . . . . . . . . . . . . . . . . .  15
   Appendix A.  The relationship between POLYVAL and GHASH . . . . .  16
   Appendix B.  Additional comparisons with AES-GCM  . . . . . . . .  18
   Appendix C.  Test vectors . . . . . . . . . . . . . . . . . . . .  18
     C.1.  AEAD_AES_128_GCM_SIV  . . . . . . . . . . . . . . . . . .  18
     C.2.  AEAD_AES_256_GCM_SIV  . . . . . . . . . . . . . . . . . .  28
     C.3.  Counter wrap tests  . . . . . . . . . . . . . . . . . . .  39
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  40

1.  Introduction

   The concept of "Authenticated encryption with additional data" (AEAD
   [RFC5116]) couples confidentiality and integrity in a single
   operation, avoiding the risks of the previously common practice of
   using ad-hoc constructions of block-cipher and hash primitives.  The
   most popular AEAD, AES-GCM [GCM], is seeing widespread use due to its
   attractive performance.

   However, some AEADs (including AES-GCM) suffer catastrophic failures
   of confidentiality and/or integrity when two distinct messages are
   encrypted with the same key and nonce.  While the requirements for
   AEADs specify that the pair of (key, nonce) shall only ever be used
   once, and thus prohibit this, in practice this is a worry.

   Nonce misuse-resistant AEADs do not suffer from this problem.  For
   this class of AEADs, encrypting two messages with the same nonce only
   discloses whether the messages were equal or not.  This is the
   minimum amount of information that a deterministic algorithm can leak
   in this situation.

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