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