sys/opencrypto/cast.c

   1 /*      $FreeBSD: src/sys/opencrypto/cast.c,v 1.4 2007/07/05 06:59:14 peter Exp $       */
   2 /*      $OpenBSD: cast.c,v 1.2 2000/06/06 06:49:47 deraadt Exp $       */
   3 /*-
   4  *      CAST-128 in C
   5  *      Written by Steve Reid <sreid@sea-to-sky.net>
   6  *      100% Public Domain - no warranty
   7  *      Released 1997.10.11
   8  */
   9
  10 #include <sys/types.h>
  11 #include <opencrypto/cast.h>
  12 #include <opencrypto/castsb.h>
  13
  14 /* Macros to access 8-bit bytes out of a 32-bit word */
  15 #define U_INT8_Ta(x) ( (u_int8_t) (x>>24) )
  16 #define U_INT8_Tb(x) ( (u_int8_t) ((x>>16)&255) )
  17 #define U_INT8_Tc(x) ( (u_int8_t) ((x>>8)&255) )
  18 #define U_INT8_Td(x) ( (u_int8_t) ((x)&255) )
  19
  20 /* Circular left shift */
  21 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) )
  22
  23 /* CAST-128 uses three different round functions */
  24 #define F1(l, r, i) \
  25         t = ROL(key->xkey[i] + r, key->xkey[i+16]); \
  26         l ^= ((cast_sbox1[U_INT8_Ta(t)] ^ cast_sbox2[U_INT8_Tb(t)]) - \
  27          cast_sbox3[U_INT8_Tc(t)]) + cast_sbox4[U_INT8_Td(t)];
  28 #define F2(l, r, i) \
  29         t = ROL(key->xkey[i] ^ r, key->xkey[i+16]); \
  30         l ^= ((cast_sbox1[U_INT8_Ta(t)] - cast_sbox2[U_INT8_Tb(t)]) + \
  31          cast_sbox3[U_INT8_Tc(t)]) ^ cast_sbox4[U_INT8_Td(t)];
  32 #define F3(l, r, i) \
  33         t = ROL(key->xkey[i] - r, key->xkey[i+16]); \
  34         l ^= ((cast_sbox1[U_INT8_Ta(t)] + cast_sbox2[U_INT8_Tb(t)]) ^ \
  35          cast_sbox3[U_INT8_Tc(t)]) - cast_sbox4[U_INT8_Td(t)];
  36
  37
  38 /***** Encryption Function *****/
  39
  40 void cast_encrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
  41 {
  42 u_int32_t t, l, r;
  43
  44         /* Get inblock into l,r */
  45         l = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
  46          ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
  47         r = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
  48          ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
  49         /* Do the work */
  50         F1(l, r,  0);
  51         F2(r, l,  1);
  52         F3(l, r,  2);
  53         F1(r, l,  3);
  54         F2(l, r,  4);
  55         F3(r, l,  5);
  56         F1(l, r,  6);
  57         F2(r, l,  7);
  58         F3(l, r,  8);
  59         F1(r, l,  9);
  60         F2(l, r, 10);
  61         F3(r, l, 11);
  62         /* Only do full 16 rounds if key length > 80 bits */
  63         if (key->rounds > 12) {
  64                 F1(l, r, 12);
  65                 F2(r, l, 13);
  66                 F3(l, r, 14);
  67                 F1(r, l, 15);
  68         }
  69         /* Put l,r into outblock */
  70         outblock[0] = U_INT8_Ta(r);
  71         outblock[1] = U_INT8_Tb(r);
  72         outblock[2] = U_INT8_Tc(r);
  73         outblock[3] = U_INT8_Td(r);
  74         outblock[4] = U_INT8_Ta(l);
  75         outblock[5] = U_INT8_Tb(l);
  76         outblock[6] = U_INT8_Tc(l);
  77         outblock[7] = U_INT8_Td(l);
  78         /* Wipe clean */
  79         t = l = r = 0;
  80 }
  81
  82
  83 /***** Decryption Function *****/
  84
  85 void cast_decrypt(cast_key* key, u_int8_t* inblock, u_int8_t* outblock)
  86 {
  87 u_int32_t t, l, r;
  88
  89         /* Get inblock into l,r */
  90         r = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) |
  91          ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3];
  92         l = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) |
  93          ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7];
  94         /* Do the work */
  95         /* Only do full 16 rounds if key length > 80 bits */
  96         if (key->rounds > 12) {
  97                 F1(r, l, 15);
  98                 F3(l, r, 14);
  99                 F2(r, l, 13);
 100                 F1(l, r, 12);
 101         }
 102         F3(r, l, 11);
 103         F2(l, r, 10);
 104         F1(r, l,  9);
 105         F3(l, r,  8);
 106         F2(r, l,  7);
 107         F1(l, r,  6);
 108         F3(r, l,  5);
 109         F2(l, r,  4);
 110         F1(r, l,  3);
 111         F3(l, r,  2);
 112         F2(r, l,  1);
 113         F1(l, r,  0);
 114         /* Put l,r into outblock */
 115         outblock[0] = U_INT8_Ta(l);
 116         outblock[1] = U_INT8_Tb(l);
 117         outblock[2] = U_INT8_Tc(l);
 118         outblock[3] = U_INT8_Td(l);
 119         outblock[4] = U_INT8_Ta(r);
 120         outblock[5] = U_INT8_Tb(r);
 121         outblock[6] = U_INT8_Tc(r);
 122         outblock[7] = U_INT8_Td(r);
 123         /* Wipe clean */
 124         t = l = r = 0;
 125 }
 126
 127
 128 /***** Key Schedual *****/
 129
 130 void cast_setkey(cast_key* key, u_int8_t* rawkey, int keybytes)
 131 {
 132         u_int32_t t[4] = {0, 0, 0, 0}, z[4] = {0, 0, 0, 0}, x[4];
 133         int i;
 134
 135         /* Set number of rounds to 12 or 16, depending on key length */
 136         key->rounds = (keybytes <= 10 ? 12 : 16);
 137
 138         /* Copy key to workspace x */
 139         for (i = 0; i < 4; i++) {
 140                 x[i] = 0;
 141                 if ((i*4+0) < keybytes) x[i] = (u_int32_t)rawkey[i*4+0] << 24;
 142                 if ((i*4+1) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+1] << 16;
 143                 if ((i*4+2) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+2] << 8;
 144                 if ((i*4+3) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+3];
 145         }
 146         /* Generate 32 subkeys, four at a time */
 147         for (i = 0; i < 32; i+=4) {
 148                 switch (i & 4) {
 149                  case 0:
 150                         t[0] = z[0] = x[0] ^ cast_sbox5[U_INT8_Tb(x[3])] ^
 151                          cast_sbox6[U_INT8_Td(x[3])] ^ cast_sbox7[U_INT8_Ta(x[3])] ^
 152                          cast_sbox8[U_INT8_Tc(x[3])] ^ cast_sbox7[U_INT8_Ta(x[2])];
 153                         t[1] = z[1] = x[2] ^ cast_sbox5[U_INT8_Ta(z[0])] ^
 154                          cast_sbox6[U_INT8_Tc(z[0])] ^ cast_sbox7[U_INT8_Tb(z[0])] ^
 155                          cast_sbox8[U_INT8_Td(z[0])] ^ cast_sbox8[U_INT8_Tc(x[2])];
 156                         t[2] = z[2] = x[3] ^ cast_sbox5[U_INT8_Td(z[1])] ^
 157                          cast_sbox6[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Tb(z[1])] ^
 158                          cast_sbox8[U_INT8_Ta(z[1])] ^ cast_sbox5[U_INT8_Tb(x[2])];
 159                         t[3] = z[3] = x[1] ^ cast_sbox5[U_INT8_Tc(z[2])] ^
 160                          cast_sbox6[U_INT8_Tb(z[2])] ^ cast_sbox7[U_INT8_Td(z[2])] ^
 161                          cast_sbox8[U_INT8_Ta(z[2])] ^ cast_sbox6[U_INT8_Td(x[2])];
 162                         break;
 163                  case 4:
 164                         t[0] = x[0] = z[2] ^ cast_sbox5[U_INT8_Tb(z[1])] ^
 165                          cast_sbox6[U_INT8_Td(z[1])] ^ cast_sbox7[U_INT8_Ta(z[1])] ^
 166                          cast_sbox8[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Ta(z[0])];
 167                         t[1] = x[1] = z[0] ^ cast_sbox5[U_INT8_Ta(x[0])] ^
 168                          cast_sbox6[U_INT8_Tc(x[0])] ^ cast_sbox7[U_INT8_Tb(x[0])] ^
 169                          cast_sbox8[U_INT8_Td(x[0])] ^ cast_sbox8[U_INT8_Tc(z[0])];
 170                         t[2] = x[2] = z[1] ^ cast_sbox5[U_INT8_Td(x[1])] ^
 171                          cast_sbox6[U_INT8_Tc(x[1])] ^ cast_sbox7[U_INT8_Tb(x[1])] ^
 172                          cast_sbox8[U_INT8_Ta(x[1])] ^ cast_sbox5[U_INT8_Tb(z[0])];
 173                         t[3] = x[3] = z[3] ^ cast_sbox5[U_INT8_Tc(x[2])] ^
 174                          cast_sbox6[U_INT8_Tb(x[2])] ^ cast_sbox7[U_INT8_Td(x[2])] ^
 175                          cast_sbox8[U_INT8_Ta(x[2])] ^ cast_sbox6[U_INT8_Td(z[0])];
 176                         break;
 177                 }
 178                 switch (i & 12) {
 179                  case 0:
 180                  case 12:
 181                         key->xkey[i+0] = cast_sbox5[U_INT8_Ta(t[2])] ^ cast_sbox6[U_INT8_Tb(t[2])] ^
 182                          cast_sbox7[U_INT8_Td(t[1])] ^ cast_sbox8[U_INT8_Tc(t[1])];
 183                         key->xkey[i+1] = cast_sbox5[U_INT8_Tc(t[2])] ^ cast_sbox6[U_INT8_Td(t[2])] ^
 184                          cast_sbox7[U_INT8_Tb(t[1])] ^ cast_sbox8[U_INT8_Ta(t[1])];
 185                         key->xkey[i+2] = cast_sbox5[U_INT8_Ta(t[3])] ^ cast_sbox6[U_INT8_Tb(t[3])] ^
 186                          cast_sbox7[U_INT8_Td(t[0])] ^ cast_sbox8[U_INT8_Tc(t[0])];
 187                         key->xkey[i+3] = cast_sbox5[U_INT8_Tc(t[3])] ^ cast_sbox6[U_INT8_Td(t[3])] ^
 188                          cast_sbox7[U_INT8_Tb(t[0])] ^ cast_sbox8[U_INT8_Ta(t[0])];
 189                         break;
 190                  case 4:
 191                  case 8:
 192                         key->xkey[i+0] = cast_sbox5[U_INT8_Td(t[0])] ^ cast_sbox6[U_INT8_Tc(t[0])] ^
 193                          cast_sbox7[U_INT8_Ta(t[3])] ^ cast_sbox8[U_INT8_Tb(t[3])];
 194                         key->xkey[i+1] = cast_sbox5[U_INT8_Tb(t[0])] ^ cast_sbox6[U_INT8_Ta(t[0])] ^
 195                          cast_sbox7[U_INT8_Tc(t[3])] ^ cast_sbox8[U_INT8_Td(t[3])];
 196                         key->xkey[i+2] = cast_sbox5[U_INT8_Td(t[1])] ^ cast_sbox6[U_INT8_Tc(t[1])] ^
 197                          cast_sbox7[U_INT8_Ta(t[2])] ^ cast_sbox8[U_INT8_Tb(t[2])];
 198                         key->xkey[i+3] = cast_sbox5[U_INT8_Tb(t[1])] ^ cast_sbox6[U_INT8_Ta(t[1])] ^
 199                          cast_sbox7[U_INT8_Tc(t[2])] ^ cast_sbox8[U_INT8_Td(t[2])];
 200                         break;
 201                 }
 202                 switch (i & 12) {
 203                  case 0:
 204                         key->xkey[i+0] ^= cast_sbox5[U_INT8_Tc(z[0])];
 205                         key->xkey[i+1] ^= cast_sbox6[U_INT8_Tc(z[1])];
 206                         key->xkey[i+2] ^= cast_sbox7[U_INT8_Tb(z[2])];
 207                         key->xkey[i+3] ^= cast_sbox8[U_INT8_Ta(z[3])];
 208                         break;
 209                  case 4:
 210                         key->xkey[i+0] ^= cast_sbox5[U_INT8_Ta(x[2])];
 211                         key->xkey[i+1] ^= cast_sbox6[U_INT8_Tb(x[3])];
 212                         key->xkey[i+2] ^= cast_sbox7[U_INT8_Td(x[0])];
 213                         key->xkey[i+3] ^= cast_sbox8[U_INT8_Td(x[1])];
 214                         break;
 215                  case 8:
 216                         key->xkey[i+0] ^= cast_sbox5[U_INT8_Tb(z[2])];
 217                         key->xkey[i+1] ^= cast_sbox6[U_INT8_Ta(z[3])];
 218                         key->xkey[i+2] ^= cast_sbox7[U_INT8_Tc(z[0])];
 219                         key->xkey[i+3] ^= cast_sbox8[U_INT8_Tc(z[1])];
 220                         break;
 221                  case 12:
 222                         key->xkey[i+0] ^= cast_sbox5[U_INT8_Td(x[0])];
 223                         key->xkey[i+1] ^= cast_sbox6[U_INT8_Td(x[1])];
 224                         key->xkey[i+2] ^= cast_sbox7[U_INT8_Ta(x[2])];
 225                         key->xkey[i+3] ^= cast_sbox8[U_INT8_Tb(x[3])];
 226                         break;
 227                 }
 228                 if (i >= 16) {
 229                         key->xkey[i+0] &= 31;
 230                         key->xkey[i+1] &= 31;
 231                         key->xkey[i+2] &= 31;
 232                         key->xkey[i+3] &= 31;
 233                 }
 234         }
 235         /* Wipe clean */
 236         for (i = 0; i < 4; i++) {
 237                 t[i] = x[i] = z[i] = 0;
 238         }
 239 }
 240
 241 /* Made in Canada */
 242