sys/opencrypto/cast.c

   1 /*      $FreeBSD: src/sys/opencrypto/cast.c,v 1.1.2.1 2002/11/21 23:34:23 sam Exp $     */
   2 /*      $DragonFly: src/sys/opencrypto/cast.c,v 1.2 2003/06/17 04:28:54 dillon Exp $    */
   3 /*      $OpenBSD: cast.c,v 1.2 2000/06/06 06:49:47 deraadt Exp $       */
   4
   5 /*
   6  *      CAST-128 in C
   7  *      Written by Steve Reid <sreid@sea-to-sky.net>
   8  *      100% Public Domain - no warranty
   9  *      Released 1997.10.11
  10  */
  11
  12 #include <sys/types.h>
  13 #include <opencrypto/cast.h>
  14 #include <opencrypto/castsb.h>
  15
  16 /* Macros to access 8-bit bytes out of a 32-bit word */
  17 #define U_INT8_Ta(x) ( (u_int8_t) (x>>24) )
  18 #define U_INT8_Tb(x) ( (u_int8_t) ((x>>16)&255) )
  19 #define U_INT8_Tc(x) ( (u_int8_t) ((x>>8)&255) )
  20 #define U_INT8_Td(x) ( (u_int8_t) ((x)&255) )
  21
  22 /* Circular left shift */
  23 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) )
  24
  25 /* CAST-128 uses three different round functions */
  26 #define F1(l, r, i) \
  27         t = ROL(key->xkey[i] + r, key->xkey[i+16]); \
  28         l ^= ((cast_sbox1[U_INT8_Ta(t)] ^ cast_sbox2[U_INT8_Tb(t)]) - \
  29          cast_sbox3[U_INT8_Tc(t)]) + cast_sbox4[U_INT8_Td(t)];
  30 #define F2(l, r, i) \
  31         t = ROL(key->xkey[i] ^ r, key->xkey[i+16]); \
  32         l ^= ((cast_sbox1[U_INT8_Ta(t)] - cast_sbox2[U_INT8_Tb(t)]) + \
  33          cast_sbox3[U_INT8_Tc(t)]) ^ cast_sbox4[U_INT8_Td(t)];
  34 #define F3(l, r, i) \
  35         t = ROL(key->xkey[i] - r, key->xkey[i+16]); \
  36         l ^= ((cast_sbox1[U_INT8_Ta(t)] + cast_sbox2[U_INT8_Tb(t)]) ^ \
  37          cast_sbox3[U_INT8_Tc(t)]) - cast_sbox4[U_INT8_Td(t)];
  38
  39
  40 /***** Encryption Function *****/
  41
  42 void cast_encrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
  43 {
  44 u_int32_t t, l, r;
  45
  46         /* Get inblock into l,r */
  47         l = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
  48          ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
  49         r = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
  50          ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
  51         /* Do the work */
  52         F1(l, r,  0);
  53         F2(r, l,  1);
  54         F3(l, r,  2);
  55         F1(r, l,  3);
  56         F2(l, r,  4);
  57         F3(r, l,  5);
  58         F1(l, r,  6);
  59         F2(r, l,  7);
  60         F3(l, r,  8);
  61         F1(r, l,  9);
  62         F2(l, r, 10);
  63         F3(r, l, 11);
  64         /* Only do full 16 rounds if key length > 80 bits */
  65         if (key->rounds > 12) {
  66                 F1(l, r, 12);
  67                 F2(r, l, 13);
  68                 F3(l, r, 14);
  69                 F1(r, l, 15);
  70         }
  71         /* Put l,r into outblock */
  72         outblock[0] = U_INT8_Ta(r);
  73         outblock[1] = U_INT8_Tb(r);
  74         outblock[2] = U_INT8_Tc(r);
  75         outblock[3] = U_INT8_Td(r);
  76         outblock[4] = U_INT8_Ta(l);
  77         outblock[5] = U_INT8_Tb(l);
  78         outblock[6] = U_INT8_Tc(l);
  79         outblock[7] = U_INT8_Td(l);
  80         /* Wipe clean */
  81         t = l = r = 0;
  82 }
  83
  84
  85 /***** Decryption Function *****/
  86
  87 void cast_decrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
  88 {
  89 u_int32_t t, l, r;
  90
  91         /* Get inblock into l,r */
  92         r = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
  93          ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
  94         l = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
  95          ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
  96         /* Do the work */
  97         /* Only do full 16 rounds if key length > 80 bits */
  98         if (key->rounds > 12) {
  99                 F1(r, l, 15);
 100                 F3(l, r, 14);
 101                 F2(r, l, 13);
 102                 F1(l, r, 12);
 103         }
 104         F3(r, l, 11);
 105         F2(l, r, 10);
 106         F1(r, l,  9);
 107         F3(l, r,  8);
 108         F2(r, l,  7);
 109         F1(l, r,  6);
 110         F3(r, l,  5);
 111         F2(l, r,  4);
 112         F1(r, l,  3);
 113         F3(l, r,  2);
 114         F2(r, l,  1);
 115         F1(l, r,  0);
 116         /* Put l,r into outblock */
 117         outblock[0] = U_INT8_Ta(l);
 118         outblock[1] = U_INT8_Tb(l);
 119         outblock[2] = U_INT8_Tc(l);
 120         outblock[3] = U_INT8_Td(l);
 121         outblock[4] = U_INT8_Ta(r);
 122         outblock[5] = U_INT8_Tb(r);
 123         outblock[6] = U_INT8_Tc(r);
 124         outblock[7] = U_INT8_Td(r);
 125         /* Wipe clean */
 126         t = l = r = 0;
 127 }
 128
 129
 130 /***** Key Schedual *****/
 131
 132 void cast_setkey(cast_key* key, u_int8_t* rawkey, int keybytes)
 133 {
 134 u_int32_t t[4], z[4], x[4];
 135 int i;
 136
 137         /* Set number of rounds to 12 or 16, depending on key length */
 138         key->rounds = (keybytes <= 10 ? 12 : 16);
 139
 140         /* Copy key to workspace x */
 141         for (i = 0; i < 4; i++) {
 142                 x[i] = 0;
 143                 if ((i*4+0) < keybytes) x[i] = (u_int32_t)rawkey[i*4+0] << 24;
 144                 if ((i*4+1) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+1] << 16;
 145                 if ((i*4+2) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+2] << 8;
 146                 if ((i*4+3) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+3];
 147         }
 148         /* Generate 32 subkeys, four at a time */
 149         for (i = 0; i < 32; i+=4) {
 150                 switch (i & 4) {
 151                  case 0:
 152                         t[0] = z[0] = x[0] ^ cast_sbox5[U_INT8_Tb(x[3])] ^
 153                          cast_sbox6[U_INT8_Td(x[3])] ^ cast_sbox7[U_INT8_Ta(x[3])] ^
 154                          cast_sbox8[U_INT8_Tc(x[3])] ^ cast_sbox7[U_INT8_Ta(x[2])];
 155                         t[1] = z[1] = x[2] ^ cast_sbox5[U_INT8_Ta(z[0])] ^
 156                          cast_sbox6[U_INT8_Tc(z[0])] ^ cast_sbox7[U_INT8_Tb(z[0])] ^
 157                          cast_sbox8[U_INT8_Td(z[0])] ^ cast_sbox8[U_INT8_Tc(x[2])];
 158                         t[2] = z[2] = x[3] ^ cast_sbox5[U_INT8_Td(z[1])] ^
 159                          cast_sbox6[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Tb(z[1])] ^
 160                          cast_sbox8[U_INT8_Ta(z[1])] ^ cast_sbox5[U_INT8_Tb(x[2])];
 161                         t[3] = z[3] = x[1] ^ cast_sbox5[U_INT8_Tc(z[2])] ^
 162                          cast_sbox6[U_INT8_Tb(z[2])] ^ cast_sbox7[U_INT8_Td(z[2])] ^
 163                          cast_sbox8[U_INT8_Ta(z[2])] ^ cast_sbox6[U_INT8_Td(x[2])];
 164                         break;
 165                  case 4:
 166                         t[0] = x[0] = z[2] ^ cast_sbox5[U_INT8_Tb(z[1])] ^
 167                          cast_sbox6[U_INT8_Td(z[1])] ^ cast_sbox7[U_INT8_Ta(z[1])] ^
 168                          cast_sbox8[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Ta(z[0])];
 169                         t[1] = x[1] = z[0] ^ cast_sbox5[U_INT8_Ta(x[0])] ^
 170                          cast_sbox6[U_INT8_Tc(x[0])] ^ cast_sbox7[U_INT8_Tb(x[0])] ^
 171                          cast_sbox8[U_INT8_Td(x[0])] ^ cast_sbox8[U_INT8_Tc(z[0])];
 172                         t[2] = x[2] = z[1] ^ cast_sbox5[U_INT8_Td(x[1])] ^
 173                          cast_sbox6[U_INT8_Tc(x[1])] ^ cast_sbox7[U_INT8_Tb(x[1])] ^
 174                          cast_sbox8[U_INT8_Ta(x[1])] ^ cast_sbox5[U_INT8_Tb(z[0])];
 175                         t[3] = x[3] = z[3] ^ cast_sbox5[U_INT8_Tc(x[2])] ^
 176                          cast_sbox6[U_INT8_Tb(x[2])] ^ cast_sbox7[U_INT8_Td(x[2])] ^
 177                          cast_sbox8[U_INT8_Ta(x[2])] ^ cast_sbox6[U_INT8_Td(z[0])];
 178                         break;
 179                 }
 180                 switch (i & 12) {
 181                  case 0:
 182                  case 12:
 183                         key->xkey[i+0] = cast_sbox5[U_INT8_Ta(t[2])] ^ cast_sbox6[U_INT8_Tb(t[2])] ^
 184                          cast_sbox7[U_INT8_Td(t[1])] ^ cast_sbox8[U_INT8_Tc(t[1])];
 185                         key->xkey[i+1] = cast_sbox5[U_INT8_Tc(t[2])] ^ cast_sbox6[U_INT8_Td(t[2])] ^
 186                          cast_sbox7[U_INT8_Tb(t[1])] ^ cast_sbox8[U_INT8_Ta(t[1])];
 187                         key->xkey[i+2] = cast_sbox5[U_INT8_Ta(t[3])] ^ cast_sbox6[U_INT8_Tb(t[3])] ^
 188                          cast_sbox7[U_INT8_Td(t[0])] ^ cast_sbox8[U_INT8_Tc(t[0])];
 189                         key->xkey[i+3] = cast_sbox5[U_INT8_Tc(t[3])] ^ cast_sbox6[U_INT8_Td(t[3])] ^
 190                          cast_sbox7[U_INT8_Tb(t[0])] ^ cast_sbox8[U_INT8_Ta(t[0])];
 191                         break;
 192                  case 4:
 193                  case 8:
 194                         key->xkey[i+0] = cast_sbox5[U_INT8_Td(t[0])] ^ cast_sbox6[U_INT8_Tc(t[0])] ^
 195                          cast_sbox7[U_INT8_Ta(t[3])] ^ cast_sbox8[U_INT8_Tb(t[3])];
 196                         key->xkey[i+1] = cast_sbox5[U_INT8_Tb(t[0])] ^ cast_sbox6[U_INT8_Ta(t[0])] ^
 197                          cast_sbox7[U_INT8_Tc(t[3])] ^ cast_sbox8[U_INT8_Td(t[3])];
 198                         key->xkey[i+2] = cast_sbox5[U_INT8_Td(t[1])] ^ cast_sbox6[U_INT8_Tc(t[1])] ^
 199                          cast_sbox7[U_INT8_Ta(t[2])] ^ cast_sbox8[U_INT8_Tb(t[2])];
 200                         key->xkey[i+3] = cast_sbox5[U_INT8_Tb(t[1])] ^ cast_sbox6[U_INT8_Ta(t[1])] ^
 201                          cast_sbox7[U_INT8_Tc(t[2])] ^ cast_sbox8[U_INT8_Td(t[2])];
 202                         break;
 203                 }
 204                 switch (i & 12) {
 205                  case 0:
 206                         key->xkey[i+0] ^= cast_sbox5[U_INT8_Tc(z[0])];
 207                         key->xkey[i+1] ^= cast_sbox6[U_INT8_Tc(z[1])];
 208                         key->xkey[i+2] ^= cast_sbox7[U_INT8_Tb(z[2])];
 209                         key->xkey[i+3] ^= cast_sbox8[U_INT8_Ta(z[3])];
 210                         break;
 211                  case 4:
 212                         key->xkey[i+0] ^= cast_sbox5[U_INT8_Ta(x[2])];
 213                         key->xkey[i+1] ^= cast_sbox6[U_INT8_Tb(x[3])];
 214                         key->xkey[i+2] ^= cast_sbox7[U_INT8_Td(x[0])];
 215                         key->xkey[i+3] ^= cast_sbox8[U_INT8_Td(x[1])];
 216                         break;
 217                  case 8:
 218                         key->xkey[i+0] ^= cast_sbox5[U_INT8_Tb(z[2])];
 219                         key->xkey[i+1] ^= cast_sbox6[U_INT8_Ta(z[3])];
 220                         key->xkey[i+2] ^= cast_sbox7[U_INT8_Tc(z[0])];
 221                         key->xkey[i+3] ^= cast_sbox8[U_INT8_Tc(z[1])];
 222                         break;
 223                  case 12:
 224                         key->xkey[i+0] ^= cast_sbox5[U_INT8_Td(x[0])];
 225                         key->xkey[i+1] ^= cast_sbox6[U_INT8_Td(x[1])];
 226                         key->xkey[i+2] ^= cast_sbox7[U_INT8_Ta(x[2])];
 227                         key->xkey[i+3] ^= cast_sbox8[U_INT8_Tb(x[3])];
 228                         break;
 229                 }
 230                 if (i >= 16) {
 231                         key->xkey[i+0] &= 31;
 232                         key->xkey[i+1] &= 31;
 233                         key->xkey[i+2] &= 31;
 234                         key->xkey[i+3] &= 31;
 235                 }
 236         }
 237         /* Wipe clean */
 238         for (i = 0; i < 4; i++) {
 239                 t[i] = x[i] = z[i] = 0;
 240         }
 241 }
 242
 243 /* Made in Canada */
 244