1 /* $NetBSD: cast128.c,v 1.10 2014/01/01 15:18:57 pgoyette 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 (at) sea-to-sky.net> 7 * 100% Public Domain - no warranty 8 * Released 1997.10.11 9 */ 10 11 #include <sys/cdefs.h> 12 __KERNEL_RCSID(0, "$NetBSD: cast128.c,v 1.10 2014/01/01 15:18:57 pgoyette Exp $"); 13 14 #include <sys/types.h> 15 #include <sys/errno.h> 16 #include <sys/module.h> 17 18 #include <crypto/cast128/cast128.h> 19 #include <crypto/cast128/cast128sb.h> 20 21 /* Macros to access 8-bit bytes out of a 32-bit word */ 22 #define U_INT8_Ta(x) ( (u_int8_t) (x>>24) ) 23 #define U_INT8_Tb(x) ( (u_int8_t) ((x>>16)&255) ) 24 #define U_INT8_Tc(x) ( (u_int8_t) ((x>>8)&255) ) 25 #define U_INT8_Td(x) ( (u_int8_t) ((x)&255) ) 26 27 /* Circular left shift */ 28 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) ) 29 30 /* CAST-128 uses three different round functions */ 31 #define F1(l, r, i) \ 32 t = ROL(key->xkey[i] + r, key->xkey[i+16]); \ 33 l ^= ((cast_sbox1[U_INT8_Ta(t)] ^ cast_sbox2[U_INT8_Tb(t)]) - \ 34 cast_sbox3[U_INT8_Tc(t)]) + cast_sbox4[U_INT8_Td(t)]; 35 #define F2(l, r, i) \ 36 t = ROL(key->xkey[i] ^ r, key->xkey[i+16]); \ 37 l ^= ((cast_sbox1[U_INT8_Ta(t)] - cast_sbox2[U_INT8_Tb(t)]) + \ 38 cast_sbox3[U_INT8_Tc(t)]) ^ cast_sbox4[U_INT8_Td(t)]; 39 #define F3(l, r, i) \ 40 t = ROL(key->xkey[i] - r, key->xkey[i+16]); \ 41 l ^= ((cast_sbox1[U_INT8_Ta(t)] + cast_sbox2[U_INT8_Tb(t)]) ^ \ 42 cast_sbox3[U_INT8_Tc(t)]) - cast_sbox4[U_INT8_Td(t)]; 43 44 45 /***** Encryption Function *****/ 46 47 void cast128_encrypt(const cast128_key* key, const u_int8_t* inblock, 48 u_int8_t* outblock) 49 { 50 u_int32_t t, l, r; 51 52 /* Get inblock into l,r */ 53 l = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) | 54 ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3]; 55 r = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) | 56 ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7]; 57 /* Do the work */ 58 F1(l, r, 0); 59 F2(r, l, 1); 60 F3(l, r, 2); 61 F1(r, l, 3); 62 F2(l, r, 4); 63 F3(r, l, 5); 64 F1(l, r, 6); 65 F2(r, l, 7); 66 F3(l, r, 8); 67 F1(r, l, 9); 68 F2(l, r, 10); 69 F3(r, l, 11); 70 /* Only do full 16 rounds if key length > 80 bits */ 71 if (key->rounds > 12) { 72 F1(l, r, 12); 73 F2(r, l, 13); 74 F3(l, r, 14); 75 F1(r, l, 15); 76 } 77 /* Put l,r into outblock */ 78 outblock[0] = U_INT8_Ta(r); 79 outblock[1] = U_INT8_Tb(r); 80 outblock[2] = U_INT8_Tc(r); 81 outblock[3] = U_INT8_Td(r); 82 outblock[4] = U_INT8_Ta(l); 83 outblock[5] = U_INT8_Tb(l); 84 outblock[6] = U_INT8_Tc(l); 85 outblock[7] = U_INT8_Td(l); 86 /* Wipe clean */ 87 t = l = r = 0; 88 } 89 90 91 /***** Decryption Function *****/ 92 93 void cast128_decrypt(const cast128_key* key, const u_int8_t* inblock, 94 u_int8_t* outblock) 95 { 96 u_int32_t t, l, r; 97 98 /* Get inblock into l,r */ 99 r = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) | 100 ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3]; 101 l = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) | 102 ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7]; 103 /* Do the work */ 104 /* Only do full 16 rounds if key length > 80 bits */ 105 if (key->rounds > 12) { 106 F1(r, l, 15); 107 F3(l, r, 14); 108 F2(r, l, 13); 109 F1(l, r, 12); 110 } 111 F3(r, l, 11); 112 F2(l, r, 10); 113 F1(r, l, 9); 114 F3(l, r, 8); 115 F2(r, l, 7); 116 F1(l, r, 6); 117 F3(r, l, 5); 118 F2(l, r, 4); 119 F1(r, l, 3); 120 F3(l, r, 2); 121 F2(r, l, 1); 122 F1(l, r, 0); 123 /* Put l,r into outblock */ 124 outblock[0] = U_INT8_Ta(l); 125 outblock[1] = U_INT8_Tb(l); 126 outblock[2] = U_INT8_Tc(l); 127 outblock[3] = U_INT8_Td(l); 128 outblock[4] = U_INT8_Ta(r); 129 outblock[5] = U_INT8_Tb(r); 130 outblock[6] = U_INT8_Tc(r); 131 outblock[7] = U_INT8_Td(r); 132 /* Wipe clean */ 133 t = l = r = 0; 134 } 135 136 137 /***** Key Schedual *****/ 138 139 void cast128_setkey(cast128_key* key, const u_int8_t* rawkey, int keybytes) 140 { 141 u_int32_t t[4], z[4], x[4]; 142 int i; 143 144 /* Set number of rounds to 12 or 16, depending on key length */ 145 key->rounds = (keybytes <= 10 ? 12 : 16); 146 147 /* Copy key to workspace x */ 148 for (i = 0; i < 4; i++) { 149 x[i] = 0; 150 t[i] = z[i] = 0; /* XXX gcc */ 151 if ((i*4+0) < keybytes) x[i] = (u_int32_t)rawkey[i*4+0] << 24; 152 if ((i*4+1) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+1] << 16; 153 if ((i*4+2) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+2] << 8; 154 if ((i*4+3) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+3]; 155 } 156 /* Generate 32 subkeys, four at a time */ 157 for (i = 0; i < 32; i+=4) { 158 switch (i & 4) { 159 case 0: 160 t[0] = z[0] = x[0] ^ cast_sbox5[U_INT8_Tb(x[3])] ^ 161 cast_sbox6[U_INT8_Td(x[3])] ^ cast_sbox7[U_INT8_Ta(x[3])] ^ 162 cast_sbox8[U_INT8_Tc(x[3])] ^ cast_sbox7[U_INT8_Ta(x[2])]; 163 t[1] = z[1] = x[2] ^ cast_sbox5[U_INT8_Ta(z[0])] ^ 164 cast_sbox6[U_INT8_Tc(z[0])] ^ cast_sbox7[U_INT8_Tb(z[0])] ^ 165 cast_sbox8[U_INT8_Td(z[0])] ^ cast_sbox8[U_INT8_Tc(x[2])]; 166 t[2] = z[2] = x[3] ^ cast_sbox5[U_INT8_Td(z[1])] ^ 167 cast_sbox6[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Tb(z[1])] ^ 168 cast_sbox8[U_INT8_Ta(z[1])] ^ cast_sbox5[U_INT8_Tb(x[2])]; 169 t[3] = z[3] = x[1] ^ cast_sbox5[U_INT8_Tc(z[2])] ^ 170 cast_sbox6[U_INT8_Tb(z[2])] ^ cast_sbox7[U_INT8_Td(z[2])] ^ 171 cast_sbox8[U_INT8_Ta(z[2])] ^ cast_sbox6[U_INT8_Td(x[2])]; 172 break; 173 case 4: 174 t[0] = x[0] = z[2] ^ cast_sbox5[U_INT8_Tb(z[1])] ^ 175 cast_sbox6[U_INT8_Td(z[1])] ^ cast_sbox7[U_INT8_Ta(z[1])] ^ 176 cast_sbox8[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Ta(z[0])]; 177 t[1] = x[1] = z[0] ^ cast_sbox5[U_INT8_Ta(x[0])] ^ 178 cast_sbox6[U_INT8_Tc(x[0])] ^ cast_sbox7[U_INT8_Tb(x[0])] ^ 179 cast_sbox8[U_INT8_Td(x[0])] ^ cast_sbox8[U_INT8_Tc(z[0])]; 180 t[2] = x[2] = z[1] ^ cast_sbox5[U_INT8_Td(x[1])] ^ 181 cast_sbox6[U_INT8_Tc(x[1])] ^ cast_sbox7[U_INT8_Tb(x[1])] ^ 182 cast_sbox8[U_INT8_Ta(x[1])] ^ cast_sbox5[U_INT8_Tb(z[0])]; 183 t[3] = x[3] = z[3] ^ cast_sbox5[U_INT8_Tc(x[2])] ^ 184 cast_sbox6[U_INT8_Tb(x[2])] ^ cast_sbox7[U_INT8_Td(x[2])] ^ 185 cast_sbox8[U_INT8_Ta(x[2])] ^ cast_sbox6[U_INT8_Td(z[0])]; 186 break; 187 } 188 switch (i & 12) { 189 case 0: 190 case 12: 191 key->xkey[i+0] = cast_sbox5[U_INT8_Ta(t[2])] ^ cast_sbox6[U_INT8_Tb(t[2])] ^ 192 cast_sbox7[U_INT8_Td(t[1])] ^ cast_sbox8[U_INT8_Tc(t[1])]; 193 key->xkey[i+1] = cast_sbox5[U_INT8_Tc(t[2])] ^ cast_sbox6[U_INT8_Td(t[2])] ^ 194 cast_sbox7[U_INT8_Tb(t[1])] ^ cast_sbox8[U_INT8_Ta(t[1])]; 195 key->xkey[i+2] = cast_sbox5[U_INT8_Ta(t[3])] ^ cast_sbox6[U_INT8_Tb(t[3])] ^ 196 cast_sbox7[U_INT8_Td(t[0])] ^ cast_sbox8[U_INT8_Tc(t[0])]; 197 key->xkey[i+3] = cast_sbox5[U_INT8_Tc(t[3])] ^ cast_sbox6[U_INT8_Td(t[3])] ^ 198 cast_sbox7[U_INT8_Tb(t[0])] ^ cast_sbox8[U_INT8_Ta(t[0])]; 199 break; 200 case 4: 201 case 8: 202 key->xkey[i+0] = cast_sbox5[U_INT8_Td(t[0])] ^ cast_sbox6[U_INT8_Tc(t[0])] ^ 203 cast_sbox7[U_INT8_Ta(t[3])] ^ cast_sbox8[U_INT8_Tb(t[3])]; 204 key->xkey[i+1] = cast_sbox5[U_INT8_Tb(t[0])] ^ cast_sbox6[U_INT8_Ta(t[0])] ^ 205 cast_sbox7[U_INT8_Tc(t[3])] ^ cast_sbox8[U_INT8_Td(t[3])]; 206 key->xkey[i+2] = cast_sbox5[U_INT8_Td(t[1])] ^ cast_sbox6[U_INT8_Tc(t[1])] ^ 207 cast_sbox7[U_INT8_Ta(t[2])] ^ cast_sbox8[U_INT8_Tb(t[2])]; 208 key->xkey[i+3] = cast_sbox5[U_INT8_Tb(t[1])] ^ cast_sbox6[U_INT8_Ta(t[1])] ^ 209 cast_sbox7[U_INT8_Tc(t[2])] ^ cast_sbox8[U_INT8_Td(t[2])]; 210 break; 211 } 212 switch (i & 12) { 213 case 0: 214 key->xkey[i+0] ^= cast_sbox5[U_INT8_Tc(z[0])]; 215 key->xkey[i+1] ^= cast_sbox6[U_INT8_Tc(z[1])]; 216 key->xkey[i+2] ^= cast_sbox7[U_INT8_Tb(z[2])]; 217 key->xkey[i+3] ^= cast_sbox8[U_INT8_Ta(z[3])]; 218 break; 219 case 4: 220 key->xkey[i+0] ^= cast_sbox5[U_INT8_Ta(x[2])]; 221 key->xkey[i+1] ^= cast_sbox6[U_INT8_Tb(x[3])]; 222 key->xkey[i+2] ^= cast_sbox7[U_INT8_Td(x[0])]; 223 key->xkey[i+3] ^= cast_sbox8[U_INT8_Td(x[1])]; 224 break; 225 case 8: 226 key->xkey[i+0] ^= cast_sbox5[U_INT8_Tb(z[2])]; 227 key->xkey[i+1] ^= cast_sbox6[U_INT8_Ta(z[3])]; 228 key->xkey[i+2] ^= cast_sbox7[U_INT8_Tc(z[0])]; 229 key->xkey[i+3] ^= cast_sbox8[U_INT8_Tc(z[1])]; 230 break; 231 case 12: 232 key->xkey[i+0] ^= cast_sbox5[U_INT8_Td(x[0])]; 233 key->xkey[i+1] ^= cast_sbox6[U_INT8_Td(x[1])]; 234 key->xkey[i+2] ^= cast_sbox7[U_INT8_Ta(x[2])]; 235 key->xkey[i+3] ^= cast_sbox8[U_INT8_Tb(x[3])]; 236 break; 237 } 238 if (i >= 16) { 239 key->xkey[i+0] &= 31; 240 key->xkey[i+1] &= 31; 241 key->xkey[i+2] &= 31; 242 key->xkey[i+3] &= 31; 243 } 244 } 245 /* Wipe clean */ 246 for (i = 0; i < 4; i++) { 247 t[i] = x[i] = z[i] = 0; 248 } 249 } 250 251 /* Made in Canada */ 252 253 #if defined(_KERNEL) 254 255 MODULE(MODULE_CLASS_MISC, cast128, NULL); 256 257 static int 258 cast128_modcmd(modcmd_t cmd, void *opaque) 259 { 260 261 switch (cmd) { 262 case MODULE_CMD_INIT: 263 return 0; 264 case MODULE_CMD_FINI: 265 return 0; 266 default: 267 return ENOTTY; 268 } 269 } 270 271 #endif /* defined(KERNEL) */ 272
Indexes created Mon Sep 22 10:09:38 GMT 2025