git.distorted.org.uk Git - u/mdw/catacomb/blob - cast128.c

   1 /* -*-c-*-
   2  *
   3  * $Id: cast128.c,v 1.1 2000/06/17 10:49:14 mdw Exp $
   4  *
   5  * The CAST-128 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: cast128.c,v $
  33  * Revision 1.1  2000/06/17 10:49:14  mdw
  34  * New cipher.
  35  *
  36  */
  37
  38 /*----- Header files ------------------------------------------------------*/
  39
  40 #include <assert.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44
  45 #include <mLib/bits.h>
  46
  47 #include "blkc.h"
  48 #include "cast-base.h"
  49 #include "cast128.h"
  50 #include "gcipher.h"
  51 #include "paranoia.h"
  52
  53 /*----- Global variables --------------------------------------------------*/
  54
  55 const octet cast128_keysz[] = { KSZ_RANGE, CAST128_KEYSZ, 0, 16, 1 };
  56
  57 /*----- Main code ---------------------------------------------------------*/
  58
  59 /* --- @cast128_init@ --- *
  60  *
  61  * Arguments:   @cast128_ctx *k@ = pointer to key block to fill in
  62  *              @const void *buf@ = pointer to buffer of key material
  63  *              @size_t sz@ = size of key material
  64  *
  65  * Returns:     ---
  66  *
  67  * Use:         Initializes a CAST-128 key buffer.  CAST-128 accepts
  68  *              128-bit keys or shorter.
  69  */
  70
  71 void cast128_init(cast128_ctx *k, const void *buf, size_t sz)
  72 {
  73   const octet *p = buf;
  74   uint32 kk[4];
  75   unsigned i;
  76   uint32 a, b, c, d,  aa, bb, cc, dd;
  77
  78   /* --- Fiddle with the key size a bit --- */
  79
  80   KSZ_ASSERT(cast128, sz);
  81
  82   if (sz > 10)
  83     k->r = 16;
  84   else
  85     k->r = 12;
  86
  87   /* --- Read the key into the array --- */
  88
  89   i = 0;
  90   b = 32; aa = 0;
  91   for (;;) {
  92     if (!sz)
  93       break;
  94     b -= 8;
  95     aa |= ((uint32)*p++ << b);
  96     sz--;
  97     if (b == 0) {
  98       kk[i++] = aa;
  99       if (i == 4)
 100         break;
 101       aa = 0;
 102       b = 32;
 103     }
 104   }
 105
 106   for (; i < 4; i++) {
 107     kk[i] = aa;
 108     aa = 0;
 109   }
 110
 111   /* --- Read the key words out --- */
 112
 113   a = kk[0]; b = kk[1]; c = kk[2]; d = kk[3];
 114
 115 #define X_0123 a
 116 #define X_4567 b
 117 #define X_89ab c
 118 #define X_cdef d
 119
 120 #define X_0 U8(X_0123 >> 24)
 121 #define X_1 U8(X_0123 >> 16)
 122 #define X_2 U8(X_0123 >>  8)
 123 #define X_3 U8(X_0123 >>  0)
 124 #define X_4 U8(X_4567 >> 24)
 125 #define X_5 U8(X_4567 >> 16)
 126 #define X_6 U8(X_4567 >>  8)
 127 #define X_7 U8(X_4567 >>  0)
 128 #define X_8 U8(X_89ab >> 24)
 129 #define X_9 U8(X_89ab >> 16)
 130 #define X_a U8(X_89ab >>  8)
 131 #define X_b U8(X_89ab >>  0)
 132 #define X_c U8(X_cdef >> 24)
 133 #define X_d U8(X_cdef >> 16)
 134 #define X_e U8(X_cdef >>  8)
 135 #define X_f U8(X_cdef >>  0)
 136
 137 #define Z_0123 aa
 138 #define Z_4567 bb
 139 #define Z_89ab cc
 140 #define Z_cdef dd
 141
 142 #define Z_0 U8(Z_0123 >> 24)
 143 #define Z_1 U8(Z_0123 >> 16)
 144 #define Z_2 U8(Z_0123 >>  8)
 145 #define Z_3 U8(Z_0123 >>  0)
 146 #define Z_4 U8(Z_4567 >> 24)
 147 #define Z_5 U8(Z_4567 >> 16)
 148 #define Z_6 U8(Z_4567 >>  8)
 149 #define Z_7 U8(Z_4567 >>  0)
 150 #define Z_8 U8(Z_89ab >> 24)
 151 #define Z_9 U8(Z_89ab >> 16)
 152 #define Z_a U8(Z_89ab >>  8)
 153 #define Z_b U8(Z_89ab >>  0)
 154 #define Z_c U8(Z_cdef >> 24)
 155 #define Z_d U8(Z_cdef >> 16)
 156 #define Z_e U8(Z_cdef >>  8)
 157 #define Z_f U8(Z_cdef >>  0)
 158
 159 #define SK(w, x, y, z)                                                  \
 160   cast_sk[0][w] ^ cast_sk[1][x] ^ cast_sk[2][y] ^ cast_sk[3][z]
 161
 162   i = 0;
 163   Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8];
 164   Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a];
 165   Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9];
 166   Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b];
 167   k->km[i++] = SK(Z_8, Z_9, Z_7, Z_6) ^ cast_sk[0][Z_2];
 168   k->km[i++] = SK(Z_a, Z_b, Z_5, Z_4) ^ cast_sk[1][Z_6];
 169   k->km[i++] = SK(Z_c, Z_d, Z_3, Z_2) ^ cast_sk[2][Z_9];
 170   k->km[i++] = SK(Z_e, Z_f, Z_1, Z_0) ^ cast_sk[3][Z_c];
 171   X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0];
 172   X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2];
 173   X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1];
 174   X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3];
 175   k->km[i++] = SK(X_3, X_2, X_c, X_d) ^ cast_sk[0][X_8];
 176   k->km[i++] = SK(X_1, X_0, X_e, X_f) ^ cast_sk[1][X_d];
 177   k->km[i++] = SK(X_7, X_6, X_8, X_9) ^ cast_sk[2][X_3];
 178   k->km[i++] = SK(X_5, X_4, X_a, X_b) ^ cast_sk[3][X_7];
 179   Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8];
 180   Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a];
 181   Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9];
 182   Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b];
 183   k->km[i++] = SK(Z_3, Z_2, Z_c, Z_d) ^ cast_sk[0][Z_9];
 184   k->km[i++] = SK(Z_1, Z_0, Z_e, Z_f) ^ cast_sk[1][Z_c];
 185   k->km[i++] = SK(Z_7, Z_6, Z_8, Z_9) ^ cast_sk[2][Z_2];
 186   k->km[i++] = SK(Z_5, Z_4, Z_a, Z_b) ^ cast_sk[3][Z_6];
 187   X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0];
 188   X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2];
 189   X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1];
 190   X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3];
 191   k->km[i++] = SK(X_8, X_9, X_7, X_6) ^ cast_sk[0][X_3];
 192   k->km[i++] = SK(X_a, X_b, X_5, X_4) ^ cast_sk[1][X_7];
 193   k->km[i++] = SK(X_c, X_d, X_3, X_2) ^ cast_sk[2][X_8];
 194   k->km[i++] = SK(X_e, X_f, X_1, X_0) ^ cast_sk[3][X_d];
 195
 196   i = 0;
 197   Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8];
 198   Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a];
 199   Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9];
 200   Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b];
 201   k->kr[i++] = (SK(Z_8, Z_9, Z_7, Z_6) ^ cast_sk[0][Z_2]) & 0x1f;
 202   k->kr[i++] = (SK(Z_a, Z_b, Z_5, Z_4) ^ cast_sk[1][Z_6]) & 0x1f;
 203   k->kr[i++] = (SK(Z_c, Z_d, Z_3, Z_2) ^ cast_sk[2][Z_9]) & 0x1f;
 204   k->kr[i++] = (SK(Z_e, Z_f, Z_1, Z_0) ^ cast_sk[3][Z_c]) & 0x1f;
 205   X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0];
 206   X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2];
 207   X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1];
 208   X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3];
 209   k->kr[i++] = (SK(X_3, X_2, X_c, X_d) ^ cast_sk[0][X_8]) & 0x1f;
 210   k->kr[i++] = (SK(X_1, X_0, X_e, X_f) ^ cast_sk[1][X_d]) & 0x1f;
 211   k->kr[i++] = (SK(X_7, X_6, X_8, X_9) ^ cast_sk[2][X_3]) & 0x1f;
 212   k->kr[i++] = (SK(X_5, X_4, X_a, X_b) ^ cast_sk[3][X_7]) & 0x1f;
 213   Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8];
 214   Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a];
 215   Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9];
 216   Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b];
 217   k->kr[i++] = (SK(Z_3, Z_2, Z_c, Z_d) ^ cast_sk[0][Z_9]) & 0x1f;
 218   k->kr[i++] = (SK(Z_1, Z_0, Z_e, Z_f) ^ cast_sk[1][Z_c]) & 0x1f;
 219   k->kr[i++] = (SK(Z_7, Z_6, Z_8, Z_9) ^ cast_sk[2][Z_2]) & 0x1f;
 220   k->kr[i++] = (SK(Z_5, Z_4, Z_a, Z_b) ^ cast_sk[3][Z_6]) & 0x1f;
 221   X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0];
 222   X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2];
 223   X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1];
 224   X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3];
 225   k->kr[i++] = (SK(X_8, X_9, X_7, X_6) ^ cast_sk[0][X_3]) & 0x1f;
 226   k->kr[i++] = (SK(X_a, X_b, X_5, X_4) ^ cast_sk[1][X_7]) & 0x1f;
 227   k->kr[i++] = (SK(X_c, X_d, X_3, X_2) ^ cast_sk[2][X_8]) & 0x1f;
 228   k->kr[i++] = (SK(X_e, X_f, X_1, X_0) ^ cast_sk[3][X_d]) & 0x1f;
 229
 230   BURN(kk);
 231 }
 232
 233 /* --- @cast128_eblk@, @cast128_dblk@ --- *
 234  *
 235  * Arguments:   @const cast128_ctx *k@ = pointer to key block
 236  *              @const uint32 s[2]@ = pointer to source block
 237  *              @uint32 d[2]@ = pointer to destination block
 238  *
 239  * Returns:     ---
 240  *
 241  * Use:         Low-level block encryption and decryption.
 242  */
 243
 244 void cast128_eblk(const cast128_ctx *k, const uint32 *s, uint32 *d)
 245 {
 246   uint32 a = s[0], b = s[1];
 247   const uint32 *km = k->km;
 248   const octet *kr = k->kr;
 249
 250   switch (k->r) {
 251     default:
 252       CAST_R1(*km++, *kr++, a, b);
 253       CAST_R2(*km++, *kr++, b, a);
 254       CAST_R3(*km++, *kr++, a, b);
 255       CAST_R1(*km++, *kr++, b, a);
 256       CAST_R2(*km++, *kr++, a, b);
 257       CAST_R3(*km++, *kr++, b, a);
 258       CAST_R1(*km++, *kr++, a, b);
 259       CAST_R2(*km++, *kr++, b, a);
 260       CAST_R3(*km++, *kr++, a, b);
 261       CAST_R1(*km++, *kr++, b, a);
 262       CAST_R2(*km++, *kr++, a, b);
 263       CAST_R3(*km++, *kr++, b, a);
 264       if (k->r == 12)
 265         break;
 266       CAST_R1(*km++, *kr++, a, b);
 267       CAST_R2(*km++, *kr++, b, a);
 268       CAST_R3(*km++, *kr++, a, b);
 269       CAST_R1(*km++, *kr++, b, a);
 270       break;
 271   }
 272
 273   d[0] = b; d[1] = a;
 274 }
 275
 276 void cast128_dblk(const cast128_ctx *k, const uint32 *s, uint32 *d)
 277 {
 278   uint32 a = s[0], b = s[1];
 279   const uint32 *km = k->km + k->r;
 280   const octet *kr = k->kr + k->r;
 281
 282   switch (k->r) {
 283     case 16:
 284     default:
 285       CAST_R1(*--km, *--kr, a, b);
 286       CAST_R3(*--km, *--kr, b, a);
 287       CAST_R2(*--km, *--kr, a, b);
 288       CAST_R1(*--km, *--kr, b, a);
 289     case 12:
 290       CAST_R3(*--km, *--kr, a, b);
 291       CAST_R2(*--km, *--kr, b, a);
 292       CAST_R1(*--km, *--kr, a, b);
 293       CAST_R3(*--km, *--kr, b, a);
 294       CAST_R2(*--km, *--kr, a, b);
 295       CAST_R1(*--km, *--kr, b, a);
 296       CAST_R3(*--km, *--kr, a, b);
 297       CAST_R2(*--km, *--kr, b, a);
 298       CAST_R1(*--km, *--kr, a, b);
 299       CAST_R3(*--km, *--kr, b, a);
 300       CAST_R2(*--km, *--kr, a, b);
 301       CAST_R1(*--km, *--kr, b, a);
 302       break;
 303   }
 304
 305   d[0] = b; d[1] = a;
 306 }
 307
 308 BLKC_TEST(CAST128, cast128)
 309
 310 /*----- That's all, folks -------------------------------------------------*/