1 /* Kernel cryptographic api. 2 * cast6.c - Cast6 cipher algorithm [rfc2612]. 3 * 4 * CAST-256 (*cast6*) is a DES like Substitution-Permutation Network (SPN) 5 * cryptosystem built upon the CAST-128 (*cast5*) [rfc2144] encryption 6 * algorithm. 7 * 8 * Copyright (C) 2003 Kartikey Mahendra Bhatt <kartik_me@hotmail.com>. 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * under the terms of GNU General Public License as published by the Free 12 * Software Foundation; either version 2 of the License, or (at your option) 13 * any later version. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA 18 */ 19 20 21 #include <asm/byteorder.h> 22 #include <linux/init.h> 23 #include <linux/crypto.h> 24 #include <linux/module.h> 25 #include <linux/errno.h> 26 #include <linux/string.h> 27 #include <linux/types.h> 28 #include <crypto/cast6.h> 29 30 #define s1 cast_s1 31 #define s2 cast_s2 32 #define s3 cast_s3 33 #define s4 cast_s4 34 35 #define F1(D, r, m) ((I = ((m) + (D))), (I = rol32(I, (r))), \ 36 (((s1[I >> 24] ^ s2[(I>>16)&0xff]) - s3[(I>>8)&0xff]) + s4[I&0xff])) 37 #define F2(D, r, m) ((I = ((m) ^ (D))), (I = rol32(I, (r))), \ 38 (((s1[I >> 24] - s2[(I>>16)&0xff]) + s3[(I>>8)&0xff]) ^ s4[I&0xff])) 39 #define F3(D, r, m) ((I = ((m) - (D))), (I = rol32(I, (r))), \ 40 (((s1[I >> 24] + s2[(I>>16)&0xff]) ^ s3[(I>>8)&0xff]) - s4[I&0xff])) 41 42 static const u32 Tm[24][8] = { 43 { 0x5a827999, 0xc95c653a, 0x383650db, 0xa7103c7c, 0x15ea281d, 44 0x84c413be, 0xf39dff5f, 0x6277eb00 } , 45 { 0xd151d6a1, 0x402bc242, 0xaf05ade3, 0x1ddf9984, 0x8cb98525, 46 0xfb9370c6, 0x6a6d5c67, 0xd9474808 } , 47 { 0x482133a9, 0xb6fb1f4a, 0x25d50aeb, 0x94aef68c, 0x0388e22d, 48 0x7262cdce, 0xe13cb96f, 0x5016a510 } , 49 { 0xbef090b1, 0x2dca7c52, 0x9ca467f3, 0x0b7e5394, 0x7a583f35, 50 0xe9322ad6, 0x580c1677, 0xc6e60218 } , 51 { 0x35bfedb9, 0xa499d95a, 0x1373c4fb, 0x824db09c, 0xf1279c3d, 52 0x600187de, 0xcedb737f, 0x3db55f20 } , 53 { 0xac8f4ac1, 0x1b693662, 0x8a432203, 0xf91d0da4, 0x67f6f945, 54 0xd6d0e4e6, 0x45aad087, 0xb484bc28 } , 55 { 0x235ea7c9, 0x9238936a, 0x01127f0b, 0x6fec6aac, 0xdec6564d, 56 0x4da041ee, 0xbc7a2d8f, 0x2b541930 } , 57 { 0x9a2e04d1, 0x0907f072, 0x77e1dc13, 0xe6bbc7b4, 0x5595b355, 58 0xc46f9ef6, 0x33498a97, 0xa2237638 } , 59 { 0x10fd61d9, 0x7fd74d7a, 0xeeb1391b, 0x5d8b24bc, 0xcc65105d, 60 0x3b3efbfe, 0xaa18e79f, 0x18f2d340 } , 61 { 0x87ccbee1, 0xf6a6aa82, 0x65809623, 0xd45a81c4, 0x43346d65, 62 0xb20e5906, 0x20e844a7, 0x8fc23048 } , 63 { 0xfe9c1be9, 0x6d76078a, 0xdc4ff32b, 0x4b29decc, 0xba03ca6d, 64 0x28ddb60e, 0x97b7a1af, 0x06918d50 } , 65 { 0x756b78f1, 0xe4456492, 0x531f5033, 0xc1f93bd4, 0x30d32775, 66 0x9fad1316, 0x0e86feb7, 0x7d60ea58 } , 67 { 0xec3ad5f9, 0x5b14c19a, 0xc9eead3b, 0x38c898dc, 0xa7a2847d, 68 0x167c701e, 0x85565bbf, 0xf4304760 } , 69 { 0x630a3301, 0xd1e41ea2, 0x40be0a43, 0xaf97f5e4, 0x1e71e185, 70 0x8d4bcd26, 0xfc25b8c7, 0x6affa468 } , 71 { 0xd9d99009, 0x48b37baa, 0xb78d674b, 0x266752ec, 0x95413e8d, 72 0x041b2a2e, 0x72f515cf, 0xe1cf0170 } , 73 { 0x50a8ed11, 0xbf82d8b2, 0x2e5cc453, 0x9d36aff4, 0x0c109b95, 74 0x7aea8736, 0xe9c472d7, 0x589e5e78 } , 75 { 0xc7784a19, 0x365235ba, 0xa52c215b, 0x14060cfc, 0x82dff89d, 76 0xf1b9e43e, 0x6093cfdf, 0xcf6dbb80 } , 77 { 0x3e47a721, 0xad2192c2, 0x1bfb7e63, 0x8ad56a04, 0xf9af55a5, 78 0x68894146, 0xd7632ce7, 0x463d1888 } , 79 { 0xb5170429, 0x23f0efca, 0x92cadb6b, 0x01a4c70c, 0x707eb2ad, 80 0xdf589e4e, 0x4e3289ef, 0xbd0c7590 } , 81 { 0x2be66131, 0x9ac04cd2, 0x099a3873, 0x78742414, 0xe74e0fb5, 82 0x5627fb56, 0xc501e6f7, 0x33dbd298 } , 83 { 0xa2b5be39, 0x118fa9da, 0x8069957b, 0xef43811c, 0x5e1d6cbd, 84 0xccf7585e, 0x3bd143ff, 0xaaab2fa0 } , 85 { 0x19851b41, 0x885f06e2, 0xf738f283, 0x6612de24, 0xd4ecc9c5, 86 0x43c6b566, 0xb2a0a107, 0x217a8ca8 } , 87 { 0x90547849, 0xff2e63ea, 0x6e084f8b, 0xdce23b2c, 0x4bbc26cd, 88 0xba96126e, 0x296ffe0f, 0x9849e9b0 } , 89 { 0x0723d551, 0x75fdc0f2, 0xe4d7ac93, 0x53b19834, 0xc28b83d5, 90 0x31656f76, 0xa03f5b17, 0x0f1946b8 } 91 }; 92 93 static const u8 Tr[4][8] = { 94 { 0x13, 0x04, 0x15, 0x06, 0x17, 0x08, 0x19, 0x0a } , 95 { 0x1b, 0x0c, 0x1d, 0x0e, 0x1f, 0x10, 0x01, 0x12 } , 96 { 0x03, 0x14, 0x05, 0x16, 0x07, 0x18, 0x09, 0x1a } , 97 { 0x0b, 0x1c, 0x0d, 0x1e, 0x0f, 0x00, 0x11, 0x02 } 98 }; 99 100 /* forward octave */ 101 static inline void W(u32 *key, unsigned int i) 102 { 103 u32 I; 104 key[6] ^= F1(key[7], Tr[i % 4][0], Tm[i][0]); 105 key[5] ^= F2(key[6], Tr[i % 4][1], Tm[i][1]); 106 key[4] ^= F3(key[5], Tr[i % 4][2], Tm[i][2]); 107 key[3] ^= F1(key[4], Tr[i % 4][3], Tm[i][3]); 108 key[2] ^= F2(key[3], Tr[i % 4][4], Tm[i][4]); 109 key[1] ^= F3(key[2], Tr[i % 4][5], Tm[i][5]); 110 key[0] ^= F1(key[1], Tr[i % 4][6], Tm[i][6]); 111 key[7] ^= F2(key[0], Tr[i % 4][7], Tm[i][7]); 112 } 113 114 int __cast6_setkey(struct cast6_ctx *c, const u8 *in_key, 115 unsigned key_len, u32 *flags) 116 { 117 int i; 118 u32 key[8]; 119 __be32 p_key[8]; /* padded key */ 120 121 if (key_len % 4 != 0) { 122 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 123 return -EINVAL; 124 } 125 126 memset(p_key, 0, 32); 127 memcpy(p_key, in_key, key_len); 128 129 key[0] = be32_to_cpu(p_key[0]); /* A */ 130 key[1] = be32_to_cpu(p_key[1]); /* B */ 131 key[2] = be32_to_cpu(p_key[2]); /* C */ 132 key[3] = be32_to_cpu(p_key[3]); /* D */ 133 key[4] = be32_to_cpu(p_key[4]); /* E */ 134 key[5] = be32_to_cpu(p_key[5]); /* F */ 135 key[6] = be32_to_cpu(p_key[6]); /* G */ 136 key[7] = be32_to_cpu(p_key[7]); /* H */ 137 138 for (i = 0; i < 12; i++) { 139 W(key, 2 * i); 140 W(key, 2 * i + 1); 141 142 c->Kr[i][0] = key[0] & 0x1f; 143 c->Kr[i][1] = key[2] & 0x1f; 144 c->Kr[i][2] = key[4] & 0x1f; 145 c->Kr[i][3] = key[6] & 0x1f; 146 147 c->Km[i][0] = key[7]; 148 c->Km[i][1] = key[5]; 149 c->Km[i][2] = key[3]; 150 c->Km[i][3] = key[1]; 151 } 152 153 return 0; 154 } 155 EXPORT_SYMBOL_GPL(__cast6_setkey); 156 157 int cast6_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) 158 { 159 return __cast6_setkey(crypto_tfm_ctx(tfm), key, keylen, 160 &tfm->crt_flags); 161 } 162 EXPORT_SYMBOL_GPL(cast6_setkey); 163 164 /*forward quad round*/ 165 static inline void Q(u32 *block, u8 *Kr, u32 *Km) 166 { 167 u32 I; 168 block[2] ^= F1(block[3], Kr[0], Km[0]); 169 block[1] ^= F2(block[2], Kr[1], Km[1]); 170 block[0] ^= F3(block[1], Kr[2], Km[2]); 171 block[3] ^= F1(block[0], Kr[3], Km[3]); 172 } 173 174 /*reverse quad round*/ 175 static inline void QBAR(u32 *block, u8 *Kr, u32 *Km) 176 { 177 u32 I; 178 block[3] ^= F1(block[0], Kr[3], Km[3]); 179 block[0] ^= F3(block[1], Kr[2], Km[2]); 180 block[1] ^= F2(block[2], Kr[1], Km[1]); 181 block[2] ^= F1(block[3], Kr[0], Km[0]); 182 } 183 184 void __cast6_encrypt(struct cast6_ctx *c, u8 *outbuf, const u8 *inbuf) 185 { 186 const __be32 *src = (const __be32 *)inbuf; 187 __be32 *dst = (__be32 *)outbuf; 188 u32 block[4]; 189 u32 *Km; 190 u8 *Kr; 191 192 block[0] = be32_to_cpu(src[0]); 193 block[1] = be32_to_cpu(src[1]); 194 block[2] = be32_to_cpu(src[2]); 195 block[3] = be32_to_cpu(src[3]); 196 197 Km = c->Km[0]; Kr = c->Kr[0]; Q(block, Kr, Km); 198 Km = c->Km[1]; Kr = c->Kr[1]; Q(block, Kr, Km); 199 Km = c->Km[2]; Kr = c->Kr[2]; Q(block, Kr, Km); 200 Km = c->Km[3]; Kr = c->Kr[3]; Q(block, Kr, Km); 201 Km = c->Km[4]; Kr = c->Kr[4]; Q(block, Kr, Km); 202 Km = c->Km[5]; Kr = c->Kr[5]; Q(block, Kr, Km); 203 Km = c->Km[6]; Kr = c->Kr[6]; QBAR(block, Kr, Km); 204 Km = c->Km[7]; Kr = c->Kr[7]; QBAR(block, Kr, Km); 205 Km = c->Km[8]; Kr = c->Kr[8]; QBAR(block, Kr, Km); 206 Km = c->Km[9]; Kr = c->Kr[9]; QBAR(block, Kr, Km); 207 Km = c->Km[10]; Kr = c->Kr[10]; QBAR(block, Kr, Km); 208 Km = c->Km[11]; Kr = c->Kr[11]; QBAR(block, Kr, Km); 209 210 dst[0] = cpu_to_be32(block[0]); 211 dst[1] = cpu_to_be32(block[1]); 212 dst[2] = cpu_to_be32(block[2]); 213 dst[3] = cpu_to_be32(block[3]); 214 } 215 EXPORT_SYMBOL_GPL(__cast6_encrypt); 216 217 static void cast6_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf) 218 { 219 __cast6_encrypt(crypto_tfm_ctx(tfm), outbuf, inbuf); 220 } 221 222 void __cast6_decrypt(struct cast6_ctx *c, u8 *outbuf, const u8 *inbuf) 223 { 224 const __be32 *src = (const __be32 *)inbuf; 225 __be32 *dst = (__be32 *)outbuf; 226 u32 block[4]; 227 u32 *Km; 228 u8 *Kr; 229 230 block[0] = be32_to_cpu(src[0]); 231 block[1] = be32_to_cpu(src[1]); 232 block[2] = be32_to_cpu(src[2]); 233 block[3] = be32_to_cpu(src[3]); 234 235 Km = c->Km[11]; Kr = c->Kr[11]; Q(block, Kr, Km); 236 Km = c->Km[10]; Kr = c->Kr[10]; Q(block, Kr, Km); 237 Km = c->Km[9]; Kr = c->Kr[9]; Q(block, Kr, Km); 238 Km = c->Km[8]; Kr = c->Kr[8]; Q(block, Kr, Km); 239 Km = c->Km[7]; Kr = c->Kr[7]; Q(block, Kr, Km); 240 Km = c->Km[6]; Kr = c->Kr[6]; Q(block, Kr, Km); 241 Km = c->Km[5]; Kr = c->Kr[5]; QBAR(block, Kr, Km); 242 Km = c->Km[4]; Kr = c->Kr[4]; QBAR(block, Kr, Km); 243 Km = c->Km[3]; Kr = c->Kr[3]; QBAR(block, Kr, Km); 244 Km = c->Km[2]; Kr = c->Kr[2]; QBAR(block, Kr, Km); 245 Km = c->Km[1]; Kr = c->Kr[1]; QBAR(block, Kr, Km); 246 Km = c->Km[0]; Kr = c->Kr[0]; QBAR(block, Kr, Km); 247 248 dst[0] = cpu_to_be32(block[0]); 249 dst[1] = cpu_to_be32(block[1]); 250 dst[2] = cpu_to_be32(block[2]); 251 dst[3] = cpu_to_be32(block[3]); 252 } 253 EXPORT_SYMBOL_GPL(__cast6_decrypt); 254 255 static void cast6_decrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf) 256 { 257 __cast6_decrypt(crypto_tfm_ctx(tfm), outbuf, inbuf); 258 } 259 260 static struct crypto_alg alg = { 261 .cra_name = "cast6", 262 .cra_driver_name = "cast6-generic", 263 .cra_priority = 100, 264 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 265 .cra_blocksize = CAST6_BLOCK_SIZE, 266 .cra_ctxsize = sizeof(struct cast6_ctx), 267 .cra_alignmask = 3, 268 .cra_module = THIS_MODULE, 269 .cra_u = { 270 .cipher = { 271 .cia_min_keysize = CAST6_MIN_KEY_SIZE, 272 .cia_max_keysize = CAST6_MAX_KEY_SIZE, 273 .cia_setkey = cast6_setkey, 274 .cia_encrypt = cast6_encrypt, 275 .cia_decrypt = cast6_decrypt} 276 } 277 }; 278 279 static int __init cast6_mod_init(void) 280 { 281 return crypto_register_alg(&alg); 282 } 283 284 static void __exit cast6_mod_fini(void) 285 { 286 crypto_unregister_alg(&alg); 287 } 288 289 module_init(cast6_mod_init); 290 module_exit(cast6_mod_fini); 291 292 MODULE_LICENSE("GPL"); 293 MODULE_DESCRIPTION("Cast6 Cipher Algorithm"); 294 MODULE_ALIAS_CRYPTO("cast6"); 295 MODULE_ALIAS_CRYPTO("cast6-generic"); 296