camellia256-set-encrypt-key.c 3.88 KB
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/* camellia256-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"

static void
_camellia256_set_encrypt_key (struct camellia256_ctx *ctx,
			      uint64_t k0, uint64_t k1,
			      uint64_t k2, uint64_t k3)
{
  uint64_t subkey[_CAMELLIA256_NKEYS + 2];
  uint64_t w;
  
  /* generate KL dependent subkeys */
  subkey[0] = k0; subkey[1] = k1;
  ROTL128(45, k0, k1);
  subkey[12] = k0; subkey[13] = k1;
  ROTL128(15, k0, k1);
  subkey[16] = k0; subkey[17] = k1;
  ROTL128(17, k0, k1);
  subkey[22] = k0; subkey[23] = k1;
  ROTL128(34, k0, k1);
  subkey[30] = k0; subkey[31] = k1;

  /* generate KR dependent subkeys */
  ROTL128(15, k2, k3);
  subkey[4] = k2; subkey[5] = k3;
  ROTL128(15, k2, k3);
  subkey[8] = k2; subkey[9] = k3;
  ROTL128(30, k2, k3);
  subkey[18] = k2; subkey[19] = k3;
  ROTL128(34, k2, k3);
  subkey[26] = k2; subkey[27] = k3;
  ROTL128(34, k2, k3);

  /* generate KA */
  /* The construction of KA is done as

     D1 = (KL ^ KR) >> 64
     D2 = (KL ^ KR) & MASK64
     W = F(D1, SIGMA1)
     D2 = D2 ^ W
     D1 = F(D2, SIGMA2) ^ (KR >> 64)
     D2 = F(D1, SIGMA3) ^ W ^ (KR & MASK64)
     D1 = D1 ^ F(W, SIGMA2)
     D2 = D2 ^ F(D1, SIGMA3)
     D1 = D1 ^ F(D2, SIGMA4)
  */

  k0 = subkey[0] ^ k2;
  k1 = subkey[1] ^ k3;

  CAMELLIA_F(k0, SIGMA1, w);
  k1 ^= w;

  CAMELLIA_F(k1, SIGMA2, k0);
  k0 ^= k2;

  CAMELLIA_F(k0, SIGMA3, k1);
  k1 ^= w ^ k3;

  CAMELLIA_F(k1, SIGMA4, w);
  k0 ^= w;

  /* generate KB */
  k2 ^= k0; k3 ^= k1;
  CAMELLIA_F(k2, SIGMA5, w);
  k3 ^= w;
  CAMELLIA_F(k3, SIGMA6, w);
  k2 ^= w;

  /* generate KA dependent subkeys */
  ROTL128(15, k0, k1);
  subkey[6] = k0; subkey[7] = k1;
  ROTL128(30, k0, k1);
  subkey[14] = k0; subkey[15] = k1;
  ROTL128(32, k0, k1);
  subkey[24] = k0; subkey[25] = k1;
  ROTL128(17, k0, k1);
  subkey[28] = k0; subkey[29] = k1;

  /* generate KB dependent subkeys */
  subkey[2] = k2; subkey[3] = k3;
  ROTL128(30, k2, k3);
  subkey[10] = k2; subkey[11] = k3;
  ROTL128(30, k2, k3);
  subkey[20] = k2; subkey[21] = k3;
  ROTL128(51, k2, k3);
  subkey[32] = k2; subkey[33] = k3;

  /* Common final processing */
  _camellia_absorb (_CAMELLIA256_NKEYS, ctx->keys, subkey);
}

void
camellia256_set_encrypt_key(struct camellia256_ctx *ctx,
			    const uint8_t *key)
{
  uint64_t k0, k1, k2, k3;
  k0 = READ_UINT64(key);
  k1 = READ_UINT64(key +  8);
  k2 = READ_UINT64(key + 16);
  k3 = READ_UINT64(key + 24);

  _camellia256_set_encrypt_key (ctx, k0, k1, k2, k3);
}

void
camellia192_set_encrypt_key(struct camellia256_ctx *ctx,
			    const uint8_t *key)
{
  uint64_t k0, k1, k2;
  k0 = READ_UINT64(key);
  k1 = READ_UINT64(key +  8);
  k2 = READ_UINT64(key + 16);

  _camellia256_set_encrypt_key (ctx, k0, k1, k2, ~k2);
}