cast128.c revision 1.7
1 /* $NetBSD: cast128.c,v 1.7 2003/08/26 20:03:57 thorpej 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 1.7 2003/08/26 20:03:57 thorpej Exp $"); 13 14 #include <sys/types.h> 15 #include <crypto/cast128/cast128.h> 16 #include <crypto/cast128/cast128sb.h> 17 18 /* Macros to access 8-bit bytes out of a 32-bit word */ 19 #define U_INT8_Ta(x) ( (u_int8_t) (x>>24) ) 20 #define U_INT8_Tb(x) ( (u_int8_t) ((x>>16)&255) ) 21 #define U_INT8_Tc(x) ( (u_int8_t) ((x>>8)&255) ) 22 #define U_INT8_Td(x) ( (u_int8_t) ((x)&255) ) 23 24 /* Circular left shift */ 25 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) ) 26 27 /* CAST-128 uses three different round functions */ 28 #define F1(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 F2(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 #define F3(l, r, i) \ 37 t = ROL(key->xkey[i] - r, key->xkey[i+16]); \ 38 l ^= ((cast_sbox1[U_INT8_Ta(t)] + cast_sbox2[U_INT8_Tb(t)]) ^ \ 39 cast_sbox3[U_INT8_Tc(t)]) - cast_sbox4[U_INT8_Td(t)]; 40 41 42 /***** Encryption Function *****/ 43 44 void cast128_encrypt(const cast128_key* key, const u_int8_t* inblock, 45 u_int8_t* outblock) 46 { 47 u_int32_t t, l, r; 48 49 /* Get inblock into l,r */ 50 l = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) | 51 ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3]; 52 r = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) | 53 ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7]; 54 /* Do the work */ 55 F1(l, r, 0); 56 F2(r, l, 1); 57 F3(l, r, 2); 58 F1(r, l, 3); 59 F2(l, r, 4); 60 F3(r, l, 5); 61 F1(l, r, 6); 62 F2(r, l, 7); 63 F3(l, r, 8); 64 F1(r, l, 9); 65 F2(l, r, 10); 66 F3(r, l, 11); 67 /* Only do full 16 rounds if key length > 80 bits */ 68 if (key->rounds > 12) { 69 F1(l, r, 12); 70 F2(r, l, 13); 71 F3(l, r, 14); 72 F1(r, l, 15); 73 } 74 /* Put l,r into outblock */ 75 outblock[0] = U_INT8_Ta(r); 76 outblock[1] = U_INT8_Tb(r); 77 outblock[2] = U_INT8_Tc(r); 78 outblock[3] = U_INT8_Td(r); 79 outblock[4] = U_INT8_Ta(l); 80 outblock[5] = U_INT8_Tb(l); 81 outblock[6] = U_INT8_Tc(l); 82 outblock[7] = U_INT8_Td(l); 83 /* Wipe clean */ 84 t = l = r = 0; 85 } 86 87 88 /***** Decryption Function *****/ 89 90 void cast128_decrypt(const cast128_key* key, const u_int8_t* inblock, 91 u_int8_t* outblock) 92 { 93 u_int32_t t, l, r; 94 95 /* Get inblock into l,r */ 96 r = ((u_int32_t)inblock[0] << 24) | ((u_int32_t)inblock[1] << 16) | 97 ((u_int32_t)inblock[2] << 8) | (u_int32_t)inblock[3]; 98 l = ((u_int32_t)inblock[4] << 24) | ((u_int32_t)inblock[5] << 16) | 99 ((u_int32_t)inblock[6] << 8) | (u_int32_t)inblock[7]; 100 /* Do the work */ 101 /* Only do full 16 rounds if key length > 80 bits */ 102 if (key->rounds > 12) { 103 F1(r, l, 15); 104 F3(l, r, 14); 105 F2(r, l, 13); 106 F1(l, r, 12); 107 } 108 F3(r, l, 11); 109 F2(l, r, 10); 110 F1(r, l, 9); 111 F3(l, r, 8); 112 F2(r, l, 7); 113 F1(l, r, 6); 114 F3(r, l, 5); 115 F2(l, r, 4); 116 F1(r, l, 3); 117 F3(l, r, 2); 118 F2(r, l, 1); 119 F1(l, r, 0); 120 /* Put l,r into outblock */ 121 outblock[0] = U_INT8_Ta(l); 122 outblock[1] = U_INT8_Tb(l); 123 outblock[2] = U_INT8_Tc(l); 124 outblock[3] = U_INT8_Td(l); 125 outblock[4] = U_INT8_Ta(r); 126 outblock[5] = U_INT8_Tb(r); 127 outblock[6] = U_INT8_Tc(r); 128 outblock[7] = U_INT8_Td(r); 129 /* Wipe clean */ 130 t = l = r = 0; 131 } 132 133 134 /***** Key Schedual *****/ 135 136 void cast128_setkey(cast128_key* key, const u_int8_t* rawkey, int keybytes) 137 { 138 u_int32_t t[4], z[4], x[4]; 139 int i; 140 141 /* Set number of rounds to 12 or 16, depending on key length */ 142 key->rounds = (keybytes <= 10 ? 12 : 16); 143 144 /* Copy key to workspace x */ 145 for (i = 0; i < 4; i++) { 146 x[i] = 0; 147 if ((i*4+0) < keybytes) x[i] = (u_int32_t)rawkey[i*4+0] << 24; 148 if ((i*4+1) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+1] << 16; 149 if ((i*4+2) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+2] << 8; 150 if ((i*4+3) < keybytes) x[i] |= (u_int32_t)rawkey[i*4+3]; 151 } 152 /* Generate 32 subkeys, four at a time */ 153 for (i = 0; i < 32; i+=4) { 154 switch (i & 4) { 155 case 0: 156 t[0] = z[0] = x[0] ^ cast_sbox5[U_INT8_Tb(x[3])] ^ 157 cast_sbox6[U_INT8_Td(x[3])] ^ cast_sbox7[U_INT8_Ta(x[3])] ^ 158 cast_sbox8[U_INT8_Tc(x[3])] ^ cast_sbox7[U_INT8_Ta(x[2])]; 159 t[1] = z[1] = x[2] ^ cast_sbox5[U_INT8_Ta(z[0])] ^ 160 cast_sbox6[U_INT8_Tc(z[0])] ^ cast_sbox7[U_INT8_Tb(z[0])] ^ 161 cast_sbox8[U_INT8_Td(z[0])] ^ cast_sbox8[U_INT8_Tc(x[2])]; 162 t[2] = z[2] = x[3] ^ cast_sbox5[U_INT8_Td(z[1])] ^ 163 cast_sbox6[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Tb(z[1])] ^ 164 cast_sbox8[U_INT8_Ta(z[1])] ^ cast_sbox5[U_INT8_Tb(x[2])]; 165 t[3] = z[3] = x[1] ^ cast_sbox5[U_INT8_Tc(z[2])] ^ 166 cast_sbox6[U_INT8_Tb(z[2])] ^ cast_sbox7[U_INT8_Td(z[2])] ^ 167 cast_sbox8[U_INT8_Ta(z[2])] ^ cast_sbox6[U_INT8_Td(x[2])]; 168 break; 169 case 4: 170 t[0] = x[0] = z[2] ^ cast_sbox5[U_INT8_Tb(z[1])] ^ 171 cast_sbox6[U_INT8_Td(z[1])] ^ cast_sbox7[U_INT8_Ta(z[1])] ^ 172 cast_sbox8[U_INT8_Tc(z[1])] ^ cast_sbox7[U_INT8_Ta(z[0])]; 173 t[1] = x[1] = z[0] ^ cast_sbox5[U_INT8_Ta(x[0])] ^ 174 cast_sbox6[U_INT8_Tc(x[0])] ^ cast_sbox7[U_INT8_Tb(x[0])] ^ 175 cast_sbox8[U_INT8_Td(x[0])] ^ cast_sbox8[U_INT8_Tc(z[0])]; 176 t[2] = x[2] = z[1] ^ cast_sbox5[U_INT8_Td(x[1])] ^ 177 cast_sbox6[U_INT8_Tc(x[1])] ^ cast_sbox7[U_INT8_Tb(x[1])] ^ 178 cast_sbox8[U_INT8_Ta(x[1])] ^ cast_sbox5[U_INT8_Tb(z[0])]; 179 t[3] = x[3] = z[3] ^ cast_sbox5[U_INT8_Tc(x[2])] ^ 180 cast_sbox6[U_INT8_Tb(x[2])] ^ cast_sbox7[U_INT8_Td(x[2])] ^ 181 cast_sbox8[U_INT8_Ta(x[2])] ^ cast_sbox6[U_INT8_Td(z[0])]; 182 break; 183 } 184 switch (i & 12) { 185 case 0: 186 case 12: 187 key->xkey[i+0] = cast_sbox5[U_INT8_Ta(t[2])] ^ cast_sbox6[U_INT8_Tb(t[2])] ^ 188 cast_sbox7[U_INT8_Td(t[1])] ^ cast_sbox8[U_INT8_Tc(t[1])]; 189 key->xkey[i+1] = cast_sbox5[U_INT8_Tc(t[2])] ^ cast_sbox6[U_INT8_Td(t[2])] ^ 190 cast_sbox7[U_INT8_Tb(t[1])] ^ cast_sbox8[U_INT8_Ta(t[1])]; 191 key->xkey[i+2] = cast_sbox5[U_INT8_Ta(t[3])] ^ cast_sbox6[U_INT8_Tb(t[3])] ^ 192 cast_sbox7[U_INT8_Td(t[0])] ^ cast_sbox8[U_INT8_Tc(t[0])]; 193 key->xkey[i+3] = cast_sbox5[U_INT8_Tc(t[3])] ^ cast_sbox6[U_INT8_Td(t[3])] ^ 194 cast_sbox7[U_INT8_Tb(t[0])] ^ cast_sbox8[U_INT8_Ta(t[0])]; 195 break; 196 case 4: 197 case 8: 198 key->xkey[i+0] = cast_sbox5[U_INT8_Td(t[0])] ^ cast_sbox6[U_INT8_Tc(t[0])] ^ 199 cast_sbox7[U_INT8_Ta(t[3])] ^ cast_sbox8[U_INT8_Tb(t[3])]; 200 key->xkey[i+1] = cast_sbox5[U_INT8_Tb(t[0])] ^ cast_sbox6[U_INT8_Ta(t[0])] ^ 201 cast_sbox7[U_INT8_Tc(t[3])] ^ cast_sbox8[U_INT8_Td(t[3])]; 202 key->xkey[i+2] = cast_sbox5[U_INT8_Td(t[1])] ^ cast_sbox6[U_INT8_Tc(t[1])] ^ 203 cast_sbox7[U_INT8_Ta(t[2])] ^ cast_sbox8[U_INT8_Tb(t[2])]; 204 key->xkey[i+3] = cast_sbox5[U_INT8_Tb(t[1])] ^ cast_sbox6[U_INT8_Ta(t[1])] ^ 205 cast_sbox7[U_INT8_Tc(t[2])] ^ cast_sbox8[U_INT8_Td(t[2])]; 206 break; 207 } 208 switch (i & 12) { 209 case 0: 210 key->xkey[i+0] ^= cast_sbox5[U_INT8_Tc(z[0])]; 211 key->xkey[i+1] ^= cast_sbox6[U_INT8_Tc(z[1])]; 212 key->xkey[i+2] ^= cast_sbox7[U_INT8_Tb(z[2])]; 213 key->xkey[i+3] ^= cast_sbox8[U_INT8_Ta(z[3])]; 214 break; 215 case 4: 216 key->xkey[i+0] ^= cast_sbox5[U_INT8_Ta(x[2])]; 217 key->xkey[i+1] ^= cast_sbox6[U_INT8_Tb(x[3])]; 218 key->xkey[i+2] ^= cast_sbox7[U_INT8_Td(x[0])]; 219 key->xkey[i+3] ^= cast_sbox8[U_INT8_Td(x[1])]; 220 break; 221 case 8: 222 key->xkey[i+0] ^= cast_sbox5[U_INT8_Tb(z[2])]; 223 key->xkey[i+1] ^= cast_sbox6[U_INT8_Ta(z[3])]; 224 key->xkey[i+2] ^= cast_sbox7[U_INT8_Tc(z[0])]; 225 key->xkey[i+3] ^= cast_sbox8[U_INT8_Tc(z[1])]; 226 break; 227 case 12: 228 key->xkey[i+0] ^= cast_sbox5[U_INT8_Td(x[0])]; 229 key->xkey[i+1] ^= cast_sbox6[U_INT8_Td(x[1])]; 230 key->xkey[i+2] ^= cast_sbox7[U_INT8_Ta(x[2])]; 231 key->xkey[i+3] ^= cast_sbox8[U_INT8_Tb(x[3])]; 232 break; 233 } 234 if (i >= 16) { 235 key->xkey[i+0] &= 31; 236 key->xkey[i+1] &= 31; 237 key->xkey[i+2] &= 31; 238 key->xkey[i+3] &= 31; 239 } 240 } 241 /* Wipe clean */ 242 for (i = 0; i < 4; i++) { 243 t[i] = x[i] = z[i] = 0; 244 } 245 } 246 247 /* Made in Canada */ 248
Indexes created Thu Oct 02 14:10:14 GMT 2025