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

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