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

   1 /* -*-c-*-
   2  *
   3  * $Id: mars.c,v 1.2 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * The MARS block cipher
   6  *
   7  * (c) 2001 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 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <assert.h>
  33 #include <stdio.h>
  34
  35 #include <mLib/bits.h>
  36
  37 #include "blkc.h"
  38 #include "gcipher.h"
  39 #include "mars.h"
  40 #include "mars-tab.h"
  41 #include "paranoia.h"
  42
  43 /*----- Global variables --------------------------------------------------*/
  44
  45 const octet mars_keysz[] = { KSZ_RANGE, MARS_KEYSZ, 0, 56, 4 };
  46
  47 /*----- Useful tables -----------------------------------------------------*/
  48
  49 static const uint32 s[512] = MARS_S;
  50 #define s0 (s +   0)
  51 #define s1 (s + 256)
  52 #define bb (s + 265)
  53
  54 /*----- Main code ---------------------------------------------------------*/
  55
  56 /* --- @mars_init@ --- *
  57  *
  58  * Arguments:   @mars_ctx *k@ = pointer to key block to fill in
  59  *              @const void *buf@ = pointer to buffer of key material
  60  *              @size_t sz@ = size of key material
  61  *
  62  * Returns:     ---
  63  *
  64  * Use:         Initializes a MARS key buffer.  MARS accepts key sizes
  65  *              between 128 and 448 bits which are a multiple of 32 bits.
  66  */
  67
  68 void mars_init(mars_ctx *k, const void *buf, size_t sz)
  69 {
  70   uint32 t[15];
  71   uint32 *kk = k->k;
  72   const octet *p;
  73   unsigned i, j, ii;
  74
  75   KSZ_ASSERT(mars, sz);
  76
  77   /* --- Copy the key into the temporary buffer --- */
  78
  79   p = buf;
  80   for (i = 0; i < sz/4; i++) {
  81     t[i] = LOAD32_L(p);
  82     p += 4;
  83   }
  84   t[i++] = sz/4;
  85   for (; i < 15; i++)
  86     t[i] = 0;
  87
  88   /* --- Now spit out the actual key material --- */
  89
  90   for (j = 0; j < 4; j++) {
  91     uint32 x;
  92
  93     /* --- Do the linear mixing stage --- */
  94
  95     for (i = 0; i < 15; i++) {
  96       x = t[(i + 8)%15] ^ t[(i + 13)%15];
  97       t[i] ^= ROL32(x, 3) ^ ((i << 2) | j);
  98     }
  99
 100     /* --- Now do the Feistel stirring stage --- */
 101
 102     x = t[14];
 103     for (ii = 0; ii < 4; ii++) {
 104       for (i = 0; i < 15; i++) {
 105         x = t[i] + s[x & 511u];
 106         t[i] = x = ROL32(x, 9);
 107       }
 108     }
 109
 110     /* --- And spit out the key material --- */
 111
 112     for (i = 0; i < 10; i++)
 113       *kk++ = t[(4 * i)%15];
 114   }
 115
 116   /* --- Finally, fix up the multiplicative entries --- */
 117
 118   for (i = 5; i < 37; i += 2) {
 119     uint32 w, m, x;
 120     j = k->k[i] & 3u;
 121     w = k->k[i] | 3u;
 122
 123     /* --- Compute the magic mask value --- */
 124
 125     m = 0;
 126     for (ii = 0; ii <= 22; ii++) {
 127       x = w >> ii;
 128       if ((x & 0x3ff) == 0x3ff || (x & 0x3ff) == 0)
 129         m |= 0x3ff << ii;
 130     }
 131     m &= ~(((w ^ (w << 1)) | (w ^ (w >> 1))) | 0x80000003);
 132
 133     /* --- Add in the bias entry to fix up the key --- */
 134
 135     x = ROL32(bb[j], k->k[i - 1]);
 136     k->k[i] = w ^ (x & m);
 137   }
 138 }
 139
 140 /* --- @mars_eblk@, @mars_dblk@ --- *
 141  *
 142  * Arguments:   @const mars_ctx *k@ = pointer to key block
 143  *              @const uint32 s[4]@ = pointer to source block
 144  *              @uint32 d[4]@ = pointer to destination block
 145  *
 146  * Returns:     ---
 147  *
 148  * Use:         Low-level block encryption and decryption.
 149  */
 150
 151 #define KADD(k, a, b, c, d)  a += *k++, b += *k++, c += *k++, d += *k++
 152 #define KSUB(k, a, b, c, d)  a -= *k++, b -= *k++, c -= *k++, d -= *k++
 153 #define IKADD(k, a, b, c, d) d += *--k, c += *--k, b += *--k, a += *--k
 154 #define IKSUB(k, a, b, c, d) d -= *--k, c -= *--k, b -= *--k, a -= *--k
 155
 156 #define MIX(a, b, c, d) do {                                            \
 157   b ^= s0[(a >>  0) & 0xff];                                            \
 158   b += s1[(a >>  8) & 0xff];                                            \
 159   c += s0[(a >> 16) & 0xff];                                            \
 160   d ^= s1[(a >> 24) & 0xff];                                            \
 161   a = ROL32(a, 8);                                                      \
 162 } while (0)
 163
 164 #define IMIX(a, b, c, d) do {                                           \
 165   a = ROR32(a, 8);                                                      \
 166   d ^= s1[(a >> 24) & 0xff];                                            \
 167   c -= s0[(a >> 16) & 0xff];                                            \
 168   b -= s1[(a >>  8) & 0xff];                                            \
 169   b ^= s0[(a >>  0) & 0xff];                                            \
 170 } while (0)
 171
 172 #define E(x, y, z, k, a) do {                                           \
 173   uint32 kx = *k++, ky = *k++;                                          \
 174   y = a + kx;                                                           \
 175   a = ROL32(a, 13); z = a * ky; z = ROL32(z, 5);                        \
 176   x = s[y & 511u] ^ z; y = ROL32(y, z);                                 \
 177   z = ROL32(z, 5); x ^= z; x = ROL32(x, z);                             \
 178 } while (0)
 179
 180 #define IE(x, y, z, k, a) do {                                          \
 181   uint32 ky = *--k, kx = *--k;                                          \
 182   z = a * ky;                                                           \
 183   a = ROR32(a, 13); y = a + kx; z = ROL32(z, 5);                        \
 184   x = s[y & 511u] ^ z; y = ROL32(y, z);                                 \
 185   z = ROL32(z, 5); x ^= z; x = ROL32(x, z);                             \
 186 } while (0)
 187
 188 #define ROUND(k, a, b, c, d) do {                                       \
 189   uint32 x, y, z;                                                       \
 190   E(x, y, z, k, a);                                                     \
 191   b += x; c += y; d ^= z;                                               \
 192 } while (0)
 193
 194 #define IROUND(k, a, b, c, d) do {                                      \
 195   uint32 x, y, z;                                                       \
 196   IE(x, y, z, k, a);                                                    \
 197   b -= x; c -= y; d ^= z;                                               \
 198 } while (0)
 199
 200 void mars_eblk(const mars_ctx *k, const uint32 *src, uint32 *dst)
 201 {
 202   uint32 a, b, c, d;
 203   const uint32 *kk = k->k;
 204
 205   a = src[0], b = src[1], c = src[2], d = src[3];
 206   KADD(kk, a, b, c, d);
 207
 208   MIX(a, b, c, d); a += d; MIX(b, c, d, a); b += c;
 209   MIX(c, d, a, b); MIX(d, a, b, c);
 210   MIX(a, b, c, d); a += d; MIX(b, c, d, a); b += c;
 211   MIX(c, d, a, b); MIX(d, a, b, c);
 212
 213   ROUND(kk, a, b, c, d); ROUND(kk, b, c, d, a);
 214   ROUND(kk, c, d, a, b); ROUND(kk, d, a, b, c);
 215   ROUND(kk, a, b, c, d); ROUND(kk, b, c, d, a);
 216   ROUND(kk, c, d, a, b); ROUND(kk, d, a, b, c);
 217
 218   ROUND(kk, a, d, c, b); ROUND(kk, b, a, d, c);
 219   ROUND(kk, c, b, a, d); ROUND(kk, d, c, b, a);
 220   ROUND(kk, a, d, c, b); ROUND(kk, b, a, d, c);
 221   ROUND(kk, c, b, a, d); ROUND(kk, d, c, b, a);
 222
 223   IMIX(a, d, c, b); IMIX(b, a, d, c);
 224   c -= b; IMIX(c, b, a, d); d -= a; IMIX(d, c, b, a);
 225   IMIX(a, d, c, b); IMIX(b, a, d, c);
 226   c -= b; IMIX(c, b, a, d); d -= a; IMIX(d, c, b, a);
 227
 228   KSUB(kk, a, b, c, d);
 229   dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d;
 230 }
 231
 232 void mars_dblk(const mars_ctx *k, const uint32 *src, uint32 *dst)
 233 {
 234   uint32 a, b, c, d;
 235   const uint32 *kk = k->k + 40;
 236
 237   a = src[0], b = src[1], c = src[2], d = src[3];
 238   IKADD(kk, a, b, c, d);
 239
 240   MIX(d, c, b, a); d += a; MIX(c, b, a, d); c += b;
 241   MIX(b, a, d, c); MIX(a, d, c, b);
 242   MIX(d, c, b, a); d += a; MIX(c, b, a, d); c += b;
 243   MIX(b, a, d, c); MIX(a, d, c, b);
 244
 245   IROUND(kk, d, c, b, a); IROUND(kk, c, b, a, d);
 246   IROUND(kk, b, a, d, c); IROUND(kk, a, d, c, b);
 247   IROUND(kk, d, c, b, a); IROUND(kk, c, b, a, d);
 248   IROUND(kk, b, a, d, c); IROUND(kk, a, d, c, b);
 249
 250   IROUND(kk, d, a, b, c); IROUND(kk, c, d, a, b);
 251   IROUND(kk, b, c, d, a); IROUND(kk, a, b, c, d);
 252   IROUND(kk, d, a, b, c); IROUND(kk, c, d, a, b);
 253   IROUND(kk, b, c, d, a); IROUND(kk, a, b, c, d);
 254
 255   IMIX(d, a, b, c); IMIX(c, d, a, b);
 256   b -= c; IMIX(b, c, d, a); a -= d; IMIX(a, b, c, d);
 257   IMIX(d, a, b, c); IMIX(c, d, a, b);
 258   b -= c; IMIX(b, c, d, a); a -= d; IMIX(a, b, c, d);
 259
 260   IKSUB(kk, a, b, c, d);
 261   dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d;
 262 }
 263
 264 BLKC_TEST(MARS, mars)
 265
 266 /*----- That's all, folks -------------------------------------------------*/