git.distorted.org.uk Git - u/mdw/catacomb/blob - rijndael.c

   1 /* -*-c-*-
   2  *
   3  * $Id: rijndael.c,v 1.4 2001/05/07 17:31:53 mdw Exp $
   4  *
   5  * The Rijndael block cipher
   6  *
   7  * (c) 2000 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: rijndael.c,v $
  33  * Revision 1.4  2001/05/07 17:31:53  mdw
  34  * Separate out key scheduling.
  35  *
  36  * Revision 1.3  2001/05/07 15:44:46  mdw
  37  * Fix unusual numbers of rounds.  Simplify implementation.
  38  *
  39  * Revision 1.2  2000/12/06 20:32:59  mdw
  40  * Fix round count for weird key sizes.
  41  *
  42  * Revision 1.1  2000/06/17 11:56:07  mdw
  43  * New cipher.
  44  *
  45  */
  46
  47 /*----- Header files ------------------------------------------------------*/
  48
  49 #include <assert.h>
  50 #include <stdio.h>
  51
  52 #include <mLib/bits.h>
  53
  54 #include "blkc.h"
  55 #include "gcipher.h"
  56 #include "rijndael.h"
  57 #include "rijndael-base.h"
  58
  59 /*----- Main code ---------------------------------------------------------*/
  60
  61 /* --- @rijndael_init@ --- *
  62  *
  63  * Arguments:   @rijndael_ctx *k@ = pointer to context to initialize
  64  *              @const void *buf@ = pointer to buffer of key material
  65  *              @size_t sz@ = size of the key material
  66  *
  67  * Returns:     ---
  68  *
  69  * Use:         Initializes a Rijndael context with a particular key.  This
  70  *              implementation of Rijndael doesn't impose any particular
  71  *              limits on the key size except that it must be multiple of 4
  72  *              bytes long.  256 bits seems sensible, though.
  73  */
  74
  75 void rijndael_init(rijndael_ctx *k, const void *buf, size_t sz)
  76 {
  77   rijndael_setup(k, RIJNDAEL_BLKSZ / 4, buf, sz);
  78 }
  79
  80 /* --- @rijndael_eblk@, @rijndael_dblk@ --- *
  81  *
  82  * Arguments:   @const rijndael_ctx *k@ = pointer to Rijndael context
  83  *              @const uint32 s[4]@ = pointer to source block
  84  *              @uint32 d[4]@ = pointer to destination block
  85  *
  86  * Returns:     ---
  87  *
  88  * Use:         Low-level block encryption and decryption.
  89  */
  90
  91 #define DO(what, t, aa, bb, cc, dd, a, b, c, d, w) do {                 \
  92   aa = what(t, a, b, c, d) ^ *w++;                                      \
  93   bb = what(t, b, c, d, a) ^ *w++;                                      \
  94   cc = what(t, c, d, a, b) ^ *w++;                                      \
  95   dd = what(t, d, a, b, c) ^ *w++;                                      \
  96 } while (0)
  97
  98 #define UNDO(what, t, aa, bb, cc, dd, a, b, c, d, w) do {               \
  99   aa = what(t, a, d, c, b) ^ *w++;                                      \
 100   bb = what(t, b, a, d, c) ^ *w++;                                      \
 101   cc = what(t, c, b, a, d) ^ *w++;                                      \
 102   dd = what(t, d, c, b, a) ^ *w++;                                      \
 103 } while (0)
 104
 105 void rijndael_eblk(const rijndael_ctx *k, const uint32 *s, uint32 *dst)
 106 {
 107   uint32 a = s[0], b = s[1], c = s[2], d = s[3];
 108   uint32 aa, bb, cc, dd;
 109   uint32 *w = k->w;
 110
 111   a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++;
 112   aa = a; bb = b; cc = c; dd = d;
 113
 114   switch (k->nr) {
 115     case 14:
 116       DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w);
 117     case 13:
 118       DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w);
 119     case 12:
 120       DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w);
 121     case 11:
 122       DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w);
 123     case 10:
 124     default:
 125       DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w);
 126       DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w);
 127       DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w);
 128       DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w);
 129       DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w);
 130       DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w);
 131       DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w);
 132       DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w);
 133       DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w);
 134   }
 135   DO(SUB, S, a, b, c, d, aa, bb, cc, dd, w);
 136
 137   dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d;
 138 }
 139
 140 void rijndael_dblk(const rijndael_ctx *k, const uint32 *s, uint32 *dst)
 141 {
 142   uint32 a = s[0], b = s[1], c = s[2], d = s[3];
 143   uint32 aa, bb, cc, dd;
 144   uint32 *w = k->wi;
 145
 146   a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++;
 147   aa = a; bb = b; cc = c; dd = d;
 148
 149   switch (k->nr) {
 150     case 14:
 151       UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w);
 152     case 13:
 153       UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w);
 154     case 12:
 155       UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w);
 156     case 11:
 157       UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w);
 158     case 10:
 159     default:
 160       UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w);
 161       UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w);
 162       UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w);
 163       UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w);
 164       UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w);
 165       UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w);
 166       UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w);
 167       UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w);
 168       UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w);
 169   }
 170   UNDO(SUB, SI, a, b, c, d, aa, bb, cc, dd, w);
 171
 172   dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d;
 173 }
 174
 175 BLKC_TEST(RIJNDAEL, rijndael)
 176
 177 /*----- That's all, folks -------------------------------------------------*/