1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis 2 * 3 * LibTomCrypt is a library that provides various cryptographic 4 * algorithms in a highly modular and flexible manner. 5 * 6 * The library is free for all purposes without any express 7 * guarantee it works. 8 * 9 * Tom St Denis, tomstdenis (at) gmail.com, http://libtomcrypt.com 10 */ 11 12 /** 13 @file rc6.c 14 RC6 code by Tom St Denis 15 */ 16 #include "tomcrypt.h" 17 18 #ifdef RC6 19 20 const struct ltc_cipher_descriptor rc6_desc = 21 { 22 "rc6", 23 3, 24 8, 128, 16, 20, 25 &rc6_setup, 26 &rc6_ecb_encrypt, 27 &rc6_ecb_decrypt, 28 &rc6_test, 29 &rc6_done, 30 &rc6_keysize, 31 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL 32 }; 33 34 static const ulong32 stab[44] = { 35 0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL, 36 0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL, 37 0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL, 38 0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL, 39 0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL, 40 0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL }; 41 42 /** 43 Initialize the RC6 block cipher 44 @param key The symmetric key you wish to pass 45 @param keylen The key length in bytes 46 @param num_rounds The number of rounds desired (0 for default) 47 @param skey The key in as scheduled by this function. 48 @return CRYPT_OK if successful 49 */ 50 #ifdef LTC_CLEAN_STACK 51 static int _rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) 52 #else 53 int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) 54 #endif 55 { 56 ulong32 L[64], S[50], A, B, i, j, v, s, l; 57 58 LTC_ARGCHK(key != NULL); 59 LTC_ARGCHK(skey != NULL); 60 61 /* test parameters */ 62 if (num_rounds != 0 && num_rounds != 20) { 63 return CRYPT_INVALID_ROUNDS; 64 } 65 66 /* key must be between 64 and 1024 bits */ 67 if (keylen < 8 || keylen > 128) { 68 return CRYPT_INVALID_KEYSIZE; 69 } 70 71 /* copy the key into the L array */ 72 for (A = i = j = 0; i < (ulong32)keylen; ) { 73 A = (A << 8) | ((ulong32)(key[i++] & 255)); 74 if (!(i & 3)) { 75 L[j++] = BSWAP(A); 76 A = 0; 77 } 78 } 79 80 /* handle odd sized keys */ 81 if (keylen & 3) { 82 A <<= (8 * (4 - (keylen&3))); 83 L[j++] = BSWAP(A); 84 } 85 86 /* setup the S array */ 87 XMEMCPY(S, stab, 44 * sizeof(stab[0])); 88 89 /* mix buffer */ 90 s = 3 * MAX(44, j); 91 l = j; 92 for (A = B = i = j = v = 0; v < s; v++) { 93 A = S[i] = ROLc(S[i] + A + B, 3); 94 B = L[j] = ROL(L[j] + A + B, (A+B)); 95 if (++i == 44) { i = 0; } 96 if (++j == l) { j = 0; } 97 } 98 99 /* copy to key */ 100 for (i = 0; i < 44; i++) { 101 skey->rc6.K[i] = S[i]; 102 } 103 return CRYPT_OK; 104 } 105 106 #ifdef LTC_CLEAN_STACK 107 int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) 108 { 109 int x; 110 x = _rc6_setup(key, keylen, num_rounds, skey); 111 burn_stack(sizeof(ulong32) * 122); 112 return x; 113 } 114 #endif 115 116 /** 117 Encrypts a block of text with RC6 118 @param pt The input plaintext (16 bytes) 119 @param ct The output ciphertext (16 bytes) 120 @param skey The key as scheduled 121 */ 122 #ifdef LTC_CLEAN_STACK 123 static int _rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) 124 #else 125 int rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) 126 #endif 127 { 128 ulong32 a,b,c,d,t,u, *K; 129 int r; 130 131 LTC_ARGCHK(skey != NULL); 132 LTC_ARGCHK(pt != NULL); 133 LTC_ARGCHK(ct != NULL); 134 LOAD32L(a,&pt[0]);LOAD32L(b,&pt[4]);LOAD32L(c,&pt[8]);LOAD32L(d,&pt[12]); 135 136 b += skey->rc6.K[0]; 137 d += skey->rc6.K[1]; 138 139 #define RND(a,b,c,d) \ 140 t = (b * (b + b + 1)); t = ROLc(t, 5); \ 141 u = (d * (d + d + 1)); u = ROLc(u, 5); \ 142 a = ROL(a^t,u) + K[0]; \ 143 c = ROL(c^u,t) + K[1]; K += 2; 144 145 K = skey->rc6.K + 2; 146 for (r = 0; r < 20; r += 4) { 147 RND(a,b,c,d); 148 RND(b,c,d,a); 149 RND(c,d,a,b); 150 RND(d,a,b,c); 151 } 152 153 #undef RND 154 155 a += skey->rc6.K[42]; 156 c += skey->rc6.K[43]; 157 STORE32L(a,&ct[0]);STORE32L(b,&ct[4]);STORE32L(c,&ct[8]);STORE32L(d,&ct[12]); 158 return CRYPT_OK; 159 } 160 161 #ifdef LTC_CLEAN_STACK 162 int rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) 163 { 164 int err = _rc6_ecb_encrypt(pt, ct, skey); 165 burn_stack(sizeof(ulong32) * 6 + sizeof(int)); 166 return err; 167 } 168 #endif 169 170 /** 171 Decrypts a block of text with RC6 172 @param ct The input ciphertext (16 bytes) 173 @param pt The output plaintext (16 bytes) 174 @param skey The key as scheduled 175 */ 176 #ifdef LTC_CLEAN_STACK 177 static int _rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) 178 #else 179 int rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) 180 #endif 181 { 182 ulong32 a,b,c,d,t,u, *K; 183 int r; 184 185 LTC_ARGCHK(skey != NULL); 186 LTC_ARGCHK(pt != NULL); 187 LTC_ARGCHK(ct != NULL); 188 189 LOAD32L(a,&ct[0]);LOAD32L(b,&ct[4]);LOAD32L(c,&ct[8]);LOAD32L(d,&ct[12]); 190 a -= skey->rc6.K[42]; 191 c -= skey->rc6.K[43]; 192 193 #define RND(a,b,c,d) \ 194 t = (b * (b + b + 1)); t = ROLc(t, 5); \ 195 u = (d * (d + d + 1)); u = ROLc(u, 5); \ 196 c = ROR(c - K[1], t) ^ u; \ 197 a = ROR(a - K[0], u) ^ t; K -= 2; 198 199 K = skey->rc6.K + 40; 200 201 for (r = 0; r < 20; r += 4) { 202 RND(d,a,b,c); 203 RND(c,d,a,b); 204 RND(b,c,d,a); 205 RND(a,b,c,d); 206 } 207 208 #undef RND 209 210 b -= skey->rc6.K[0]; 211 d -= skey->rc6.K[1]; 212 STORE32L(a,&pt[0]);STORE32L(b,&pt[4]);STORE32L(c,&pt[8]);STORE32L(d,&pt[12]); 213 214 return CRYPT_OK; 215 } 216 217 #ifdef LTC_CLEAN_STACK 218 int rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) 219 { 220 int err = _rc6_ecb_decrypt(ct, pt, skey); 221 burn_stack(sizeof(ulong32) * 6 + sizeof(int)); 222 return err; 223 } 224 #endif 225 226 /** 227 Performs a self-test of the RC6 block cipher 228 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled 229 */ 230 int rc6_test(void) 231 { 232 #ifndef LTC_TEST 233 return CRYPT_NOP; 234 #else 235 static const struct { 236 int keylen; 237 unsigned char key[32], pt[16], ct[16]; 238 } tests[] = { 239 { 240 16, 241 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 242 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 243 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 244 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, 245 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 246 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, 247 { 0x52, 0x4e, 0x19, 0x2f, 0x47, 0x15, 0xc6, 0x23, 248 0x1f, 0x51, 0xf6, 0x36, 0x7e, 0xa4, 0x3f, 0x18 } 249 }, 250 { 251 24, 252 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 253 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 254 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0, 255 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, 256 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 257 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, 258 { 0x68, 0x83, 0x29, 0xd0, 0x19, 0xe5, 0x05, 0x04, 259 0x1e, 0x52, 0xe9, 0x2a, 0xf9, 0x52, 0x91, 0xd4 } 260 }, 261 { 262 32, 263 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 264 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 265 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0, 266 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe }, 267 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 268 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, 269 { 0xc8, 0x24, 0x18, 0x16, 0xf0, 0xd7, 0xe4, 0x89, 270 0x20, 0xad, 0x16, 0xa1, 0x67, 0x4e, 0x5d, 0x48 } 271 } 272 }; 273 unsigned char tmp[2][16]; 274 int x, y, err; 275 symmetric_key key; 276 277 for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) { 278 /* setup key */ 279 if ((err = rc6_setup(tests[x].key, tests[x].keylen, 0, &key)) != CRYPT_OK) { 280 return err; 281 } 282 283 /* encrypt and decrypt */ 284 rc6_ecb_encrypt(tests[x].pt, tmp[0], &key); 285 rc6_ecb_decrypt(tmp[0], tmp[1], &key); 286 287 /* compare */ 288 if (XMEMCMP(tmp[0], tests[x].ct, 16) || XMEMCMP(tmp[1], tests[x].pt, 16)) { 289 #if 0 290 printf("\n\nFailed test %d\n", x); 291 if (XMEMCMP(tmp[0], tests[x].ct, 16)) { 292 printf("Ciphertext: "); 293 for (y = 0; y < 16; y++) printf("%02x ", tmp[0][y]); 294 printf("\nExpected : "); 295 for (y = 0; y < 16; y++) printf("%02x ", tests[x].ct[y]); 296 printf("\n"); 297 } 298 if (XMEMCMP(tmp[1], tests[x].pt, 16)) { 299 printf("Plaintext: "); 300 for (y = 0; y < 16; y++) printf("%02x ", tmp[0][y]); 301 printf("\nExpected : "); 302 for (y = 0; y < 16; y++) printf("%02x ", tests[x].pt[y]); 303 printf("\n"); 304 } 305 #endif 306 return CRYPT_FAIL_TESTVECTOR; 307 } 308 309 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */ 310 for (y = 0; y < 16; y++) tmp[0][y] = 0; 311 for (y = 0; y < 1000; y++) rc6_ecb_encrypt(tmp[0], tmp[0], &key); 312 for (y = 0; y < 1000; y++) rc6_ecb_decrypt(tmp[0], tmp[0], &key); 313 for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR; 314 } 315 return CRYPT_OK; 316 #endif 317 } 318 319 /** Terminate the context 320 @param skey The scheduled key 321 */ 322 void rc6_done(symmetric_key *skey) 323 { 324 } 325 326 /** 327 Gets suitable key size 328 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable. 329 @return CRYPT_OK if the input key size is acceptable. 330 */ 331 int rc6_keysize(int *keysize) 332 { 333 LTC_ARGCHK(keysize != NULL); 334 if (*keysize < 8) { 335 return CRYPT_INVALID_KEYSIZE; 336 } else if (*keysize > 128) { 337 *keysize = 128; 338 } 339 return CRYPT_OK; 340 } 341 342 #endif /*RC6*/ 343 344 345 346 /* $Source: /cvs/libtom/libtomcrypt/src/ciphers/rc6.c,v $ */ 347 /* $Revision: 1.12 $ */ 348 /* $Date: 2006/11/08 23:01:06 $ */ 349
