camellia-absorb.c 3.74 KB
Newer Older
Niels Möller's avatar
Niels Möller committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135
/* camellia-absorb.c
 *
 * Final key setup processing for the camellia block cipher.
 */
/*
 * Copyright (C) 2006,2007
 * NTT (Nippon Telegraph and Telephone Corporation).
 *
 * Copyright (C) 2010 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 "camellia-internal.h"

#include "macros.h"

void
_camellia_absorb(unsigned nkeys, uint64_t *dst, uint64_t *subkey)
{
  uint64_t kw2, kw4;
  uint32_t dw, tl, tr;
  unsigned i;
  
  /* At this point, the subkey array contains the subkeys as described
     in the spec, 26 for short keys and 34 for large keys. */

  /* absorb kw2 to other subkeys */
  kw2 = subkey[1];

  subkey[3] ^= kw2;
  subkey[5] ^= kw2;
  subkey[7] ^= kw2;
  for (i = 8; i < nkeys; i += 8)
    {
      /* FIXME: gcc for x86_32 is smart enough to fetch the 32 low bits
	 and xor the result into the 32 high bits, but it still generates
	 worse code than for explicit 32-bit operations. */
      kw2 ^= (kw2 & ~subkey[i+1]) << 32;
      dw = (kw2 & subkey[i+1]) >> 32; kw2 ^= ROTL32(1, dw); 

      subkey[i+3] ^= kw2;
      subkey[i+5] ^= kw2;
      subkey[i+7] ^= kw2;
    }
  subkey[i] ^= kw2;
  
  /* absorb kw4 to other subkeys */  
  kw4 = subkey[nkeys + 1];

  for (i = nkeys - 8; i > 0; i -= 8)
    {
      subkey[i+6] ^= kw4;
      subkey[i+4] ^= kw4;
      subkey[i+2] ^= kw4;
      kw4 ^= (kw4 & ~subkey[i]) << 32;
      dw = (kw4 & subkey[i]) >> 32; kw4 ^= ROTL32(1, dw);      
    }

  subkey[6] ^= kw4;
  subkey[4] ^= kw4;
  subkey[2] ^= kw4;
  subkey[0] ^= kw4;

  /* key XOR is end of F-function */
  dst[0] = subkey[0] ^ subkey[2];
  dst[1] = subkey[3];

  dst[2] = subkey[2] ^ subkey[4];
  dst[3] = subkey[3] ^ subkey[5];
  dst[4] = subkey[4] ^ subkey[6];
  dst[5] = subkey[5] ^ subkey[7];

  for (i = 8; i < nkeys; i += 8)
    {
      tl = (subkey[i+2] >> 32) ^ (subkey[i+2] & ~subkey[i]);
      dw = tl & (subkey[i] >> 32);
      tr = subkey[i+2] ^ ROTL32(1, dw);
      dst[i-2] = subkey[i-2] ^ ( ((uint64_t) tl << 32) | tr);

      dst[i-1] = subkey[i];
      dst[i] = subkey[i+1];

      tl = (subkey[i-1] >> 32) ^ (subkey[i-1] & ~subkey[i+1]);
      dw = tl & (subkey[i+1] >> 32);
      tr = subkey[i-1] ^ ROTL32(1, dw);
      dst[i+1] = subkey[i+3] ^ ( ((uint64_t) tl << 32) | tr);

      dst[i+2] = subkey[i+2] ^ subkey[i+4];
      dst[i+3] = subkey[i+3] ^ subkey[i+5];
      dst[i+4] = subkey[i+4] ^ subkey[i+6];
      dst[i+5] = subkey[i+5] ^ subkey[i+7];
    }
  dst[i-2] = subkey[i-2];
  dst[i-1] = subkey[i] ^ subkey[i-1];

#if !HAVE_NATIVE_64_BIT
  for (i = 0; i < nkeys; i += 8)
    {
      /* apply the inverse of the last half of F-function */
      CAMELLIA_F_HALF_INV(dst[i+1]);
      CAMELLIA_F_HALF_INV(dst[i+2]);
      CAMELLIA_F_HALF_INV(dst[i+3]);
      CAMELLIA_F_HALF_INV(dst[i+4]);
      CAMELLIA_F_HALF_INV(dst[i+5]);
      CAMELLIA_F_HALF_INV(dst[i+6]);
    }
#endif
  
}