Hash-Encrypt-Hash, a block cipher mode of operation
draft-cope-heh-01

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Crypto Forum Research Group                                      A. Cope
Internet-Draft                                                    Google
Intended status: Informational                         December 21, 2016
Expires: June 24, 2017

          Hash-Encrypt-Hash, a block cipher mode of operation
                           draft-cope-heh-01

Abstract

   This memo describes a block cipher mode of operation known as Hash-
   Encrypt-Hash (HEH).

Status of This Memo

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   This Internet-Draft will expire on June 24, 2017.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Cope                      Expires June 24, 2017                 [Page 1]
Internet-Draft                     HEH                     December 2016

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Notation  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Key size  . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Block cipher  . . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  Nonce and AAD . . . . . . . . . . . . . . . . . . . . . .   4
   4.  GF(2^128) math  . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  GF(2^128) . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  Multiplication in GF(2^128) . . . . . . . . . . . . . . .   4
     4.3.  Addition in GF(2^128) . . . . . . . . . . . . . . . . . .   5
   5.  Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     5.1.  generate_keys . . . . . . . . . . . . . . . . . . . . . .   5
     5.2.  generate_betas  . . . . . . . . . . . . . . . . . . . . .   6
     5.3.  poly_hash . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.4.  HEH_hash  . . . . . . . . . . . . . . . . . . . . . . . .   7
     5.5.  HEH_hash_inv  . . . . . . . . . . . . . . . . . . . . . .   8
     5.6.  CTS_2ECB_encrypt  . . . . . . . . . . . . . . . . . . . .   9
     5.7.  CTS_2ECB_decrypt  . . . . . . . . . . . . . . . . . . . .   9
     5.8.  HEH_encrypt . . . . . . . . . . . . . . . . . . . . . . .  10
     5.9.  HEH_decrypt . . . . . . . . . . . . . . . . . . . . . . .  10
   6.  HEH as an AEAD  . . . . . . . . . . . . . . . . . . . . . . .  10
     6.1.  HEH_AEAD_encrypt  . . . . . . . . . . . . . . . . . . . .  10
     6.2.  HEH_AEAD_decrypt  . . . . . . . . . . . . . . . . . . . .  11
   7.  Security considerations . . . . . . . . . . . . . . . . . . .  11
     7.1.  Security implementations of nonce use . . . . . . . . . .  11
     7.2.  Authentication  . . . . . . . . . . . . . . . . . . . . .  12
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Appendix A.  Test Vectors . . . . . . . . . . . . . . . . . . . .  12
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   This memo describes the implementation of the Hash Encrypt Hash (HEH)
   block cipher mode of operation as both an encryption algorithm and an
   AEAD.  The primary benefit of HEH is that it extends the strong
   pseudorandom permutation property of block ciphers to arbitrary-
   length messages.  This means that if any bit of the plaintext is
   flipped, each bit in the ciphertext will flip with 50% probability.
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