camellia128-set-encrypt-key.c

/* camellia128-set-encrypt-key.c
 *
 * Key setup for the camellia block cipher.
 */
/*
 * Copyright (C) 2006,2007
 * NTT (Nippon Telegraph and Telephone Corporation).
 *
 * Copyright (C) 2010, 2013 Niels Möller
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

/*
 * Algorithm Specification 
 *  http://info.isl.ntt.co.jp/crypt/eng/camellia/specifications.html
 */

/* Based on camellia.c ver 1.2.0, see
   http://info.isl.ntt.co.jp/crypt/eng/camellia/dl/camellia-LGPL-1.2.0.tar.gz.
 */
#if HAVE_CONFIG_H
# include "config.h"
#endif

#include <assert.h>
#include <limits.h>

#include "camellia-internal.h"

#include "macros.h"

void
camellia128_set_encrypt_key (struct camellia128_ctx *ctx,
			     const uint8_t *key)
{
  uint64_t k0, k1;

  uint64_t subkey[_CAMELLIA128_NKEYS + 2];
  uint64_t w;

  k0 = READ_UINT64(key);
  k1 = READ_UINT64(key +  8);
  
  /**
   * generate KL dependent subkeys
   */
  subkey[0] = k0; subkey[1] = k1;
  ROTL128(15, k0, k1);
  subkey[4] = k0; subkey[5] = k1;
  ROTL128(30, k0, k1);
  subkey[10] = k0; subkey[11] = k1;
  ROTL128(15, k0, k1);
  subkey[13] = k1;
  ROTL128(17, k0, k1);
  subkey[16] = k0; subkey[17] = k1;
  ROTL128(17, k0, k1);
  subkey[18] = k0; subkey[19] = k1;
  ROTL128(17, k0, k1);
  subkey[22] = k0; subkey[23] = k1;

  /* generate KA. D1 is k0, d2 is k1. */
  /* FIXME: Make notation match the spec better. */
  /* For the 128-bit case, KR = 0, the construction of KA reduces to:

     D1 = KL >> 64;
     W = KL & MASK64;
     D2 = F(D1, Sigma1);
     W = D2 ^ W
     D1 = F(W, Sigma2)
     D2 = D2 ^ F(D1, Sigma3);
     D1 = D1 ^ F(D2, Sigma4);
     KA = (D1 << 64) | D2;
  */
  k0 = subkey[0]; w = subkey[1];
  CAMELLIA_F(k0, SIGMA1, k1);
  w ^= k1;
  CAMELLIA_F(w, SIGMA2, k0);
  CAMELLIA_F(k0, SIGMA3, w);
  k1 ^= w;
  CAMELLIA_F(k1, SIGMA4, w);
  k0 ^= w;

  /* generate KA dependent subkeys */
  subkey[2] = k0; subkey[3] = k1;
  ROTL128(15, k0, k1);
  subkey[6] = k0; subkey[7] = k1;
  ROTL128(15, k0, k1);
  subkey[8] = k0; subkey[9] = k1;
  ROTL128(15, k0, k1);
  subkey[12] = k0;
  ROTL128(15, k0, k1);
  subkey[14] = k0; subkey[15] = k1;
  ROTL128(34, k0, k1);
  subkey[20] = k0; subkey[21] = k1;
  ROTL128(17, k0, k1);
  subkey[24] = k0; subkey[25] = k1;

  /* Common final processing */
  _camellia_absorb (_CAMELLIA128_NKEYS, ctx->keys, subkey);
}