aes-invert-internal.c 5.35 KB
Newer Older
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156
/* aes-invert-internal.c
 *
 * Inverse key setup for the aes/rijndael block cipher.
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2000, 2001, 2002, Rafael R. Sevilla, Niels Möller
 * Copyright (C) 2013 Niels Möller
 *  
 * The nettle 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.
 * 
 * The nettle 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 the nettle library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02111-1301, USA.
 */

/* Originally written by Rafael R. Sevilla <dido@pacific.net.ph> */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include "aes-internal.h"

#include "macros.h"

/* NOTE: We don't include rotated versions of the table. */
static const uint32_t mtable[0x100] =
{
  0x00000000,0x0b0d090e,0x161a121c,0x1d171b12,
  0x2c342438,0x27392d36,0x3a2e3624,0x31233f2a,
  0x58684870,0x5365417e,0x4e725a6c,0x457f5362,
  0x745c6c48,0x7f516546,0x62467e54,0x694b775a,
  0xb0d090e0,0xbbdd99ee,0xa6ca82fc,0xadc78bf2,
  0x9ce4b4d8,0x97e9bdd6,0x8afea6c4,0x81f3afca,
  0xe8b8d890,0xe3b5d19e,0xfea2ca8c,0xf5afc382,
  0xc48cfca8,0xcf81f5a6,0xd296eeb4,0xd99be7ba,
  0x7bbb3bdb,0x70b632d5,0x6da129c7,0x66ac20c9,
  0x578f1fe3,0x5c8216ed,0x41950dff,0x4a9804f1,
  0x23d373ab,0x28de7aa5,0x35c961b7,0x3ec468b9,
  0x0fe75793,0x04ea5e9d,0x19fd458f,0x12f04c81,
  0xcb6bab3b,0xc066a235,0xdd71b927,0xd67cb029,
  0xe75f8f03,0xec52860d,0xf1459d1f,0xfa489411,
  0x9303e34b,0x980eea45,0x8519f157,0x8e14f859,
  0xbf37c773,0xb43ace7d,0xa92dd56f,0xa220dc61,
  0xf66d76ad,0xfd607fa3,0xe07764b1,0xeb7a6dbf,
  0xda595295,0xd1545b9b,0xcc434089,0xc74e4987,
  0xae053edd,0xa50837d3,0xb81f2cc1,0xb31225cf,
  0x82311ae5,0x893c13eb,0x942b08f9,0x9f2601f7,
  0x46bde64d,0x4db0ef43,0x50a7f451,0x5baafd5f,
  0x6a89c275,0x6184cb7b,0x7c93d069,0x779ed967,
  0x1ed5ae3d,0x15d8a733,0x08cfbc21,0x03c2b52f,
  0x32e18a05,0x39ec830b,0x24fb9819,0x2ff69117,
  0x8dd64d76,0x86db4478,0x9bcc5f6a,0x90c15664,
  0xa1e2694e,0xaaef6040,0xb7f87b52,0xbcf5725c,
  0xd5be0506,0xdeb30c08,0xc3a4171a,0xc8a91e14,
  0xf98a213e,0xf2872830,0xef903322,0xe49d3a2c,
  0x3d06dd96,0x360bd498,0x2b1ccf8a,0x2011c684,
  0x1132f9ae,0x1a3ff0a0,0x0728ebb2,0x0c25e2bc,
  0x656e95e6,0x6e639ce8,0x737487fa,0x78798ef4,
  0x495ab1de,0x4257b8d0,0x5f40a3c2,0x544daacc,
  0xf7daec41,0xfcd7e54f,0xe1c0fe5d,0xeacdf753,
  0xdbeec879,0xd0e3c177,0xcdf4da65,0xc6f9d36b,
  0xafb2a431,0xa4bfad3f,0xb9a8b62d,0xb2a5bf23,
  0x83868009,0x888b8907,0x959c9215,0x9e919b1b,
  0x470a7ca1,0x4c0775af,0x51106ebd,0x5a1d67b3,
  0x6b3e5899,0x60335197,0x7d244a85,0x7629438b,
  0x1f6234d1,0x146f3ddf,0x097826cd,0x02752fc3,
  0x335610e9,0x385b19e7,0x254c02f5,0x2e410bfb,
  0x8c61d79a,0x876cde94,0x9a7bc586,0x9176cc88,
  0xa055f3a2,0xab58faac,0xb64fe1be,0xbd42e8b0,
  0xd4099fea,0xdf0496e4,0xc2138df6,0xc91e84f8,
  0xf83dbbd2,0xf330b2dc,0xee27a9ce,0xe52aa0c0,
  0x3cb1477a,0x37bc4e74,0x2aab5566,0x21a65c68,
  0x10856342,0x1b886a4c,0x069f715e,0x0d927850,
  0x64d90f0a,0x6fd40604,0x72c31d16,0x79ce1418,
  0x48ed2b32,0x43e0223c,0x5ef7392e,0x55fa3020,
  0x01b79aec,0x0aba93e2,0x17ad88f0,0x1ca081fe,
  0x2d83bed4,0x268eb7da,0x3b99acc8,0x3094a5c6,
  0x59dfd29c,0x52d2db92,0x4fc5c080,0x44c8c98e,
  0x75ebf6a4,0x7ee6ffaa,0x63f1e4b8,0x68fcedb6,
  0xb1670a0c,0xba6a0302,0xa77d1810,0xac70111e,
  0x9d532e34,0x965e273a,0x8b493c28,0x80443526,
  0xe90f427c,0xe2024b72,0xff155060,0xf418596e,
  0xc53b6644,0xce366f4a,0xd3217458,0xd82c7d56,
  0x7a0ca137,0x7101a839,0x6c16b32b,0x671bba25,
  0x5638850f,0x5d358c01,0x40229713,0x4b2f9e1d,
  0x2264e947,0x2969e049,0x347efb5b,0x3f73f255,
  0x0e50cd7f,0x055dc471,0x184adf63,0x1347d66d,
  0xcadc31d7,0xc1d138d9,0xdcc623cb,0xd7cb2ac5,
  0xe6e815ef,0xede51ce1,0xf0f207f3,0xfbff0efd,
  0x92b479a7,0x99b970a9,0x84ae6bbb,0x8fa362b5,
  0xbe805d9f,0xb58d5491,0xa89a4f83,0xa397468d,
};

#define MIX_COLUMN(T, key) do { \
    uint32_t _k, _nk, _t;	\
    _k = (key);			\
    _nk = T[_k & 0xff];		\
    _k >>= 8;			\
    _t = T[_k & 0xff];		\
    _nk ^= ROTL32(8, _t);	\
    _k >>= 8;			\
    _t = T[_k & 0xff];		\
    _nk ^= ROTL32(16, _t);	\
    _k >>= 8;			\
    _t = T[_k & 0xff];		\
    _nk ^= ROTL32(24, _t);	\
    (key) = _nk;		\
  } while(0)
  

#define SWAP(a, b) \
do { uint32_t t_swap = (a); (a) = (b); (b) = t_swap; } while(0)

void
_aes_invert(unsigned rounds, uint32_t *dst, const uint32_t *src)
{
  unsigned i;

  /* Reverse the order of subkeys, in groups of 4. */
  /* FIXME: Instead of reordering the subkeys, change the access order
     of aes_decrypt, since it's a separate function anyway? */
  if (src == dst)
    {
      unsigned j, k;

      for (i = 0, j = rounds * 4;
	   i < j;
	   i += 4, j -= 4)
	for (k = 0; k<4; k++)
	  SWAP(dst[i+k], dst[j+k]);
    }
  else
    {
      unsigned k;

      for (i = 0; i <= rounds * 4; i += 4)
	for (k = 0; k < 4; k++)
	  dst[i+k] = src[rounds * 4 - i + k];
    }

  /* Transform all subkeys but the first and last. */
  for (i = 4; i < 4 * rounds; i++)
    MIX_COLUMN (mtable, dst[i]);
}