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 */ 244 245