1 // SPDX-License-Identifier: BSD-2-Clause 2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis 3 * 4 * LibTomCrypt is a library that provides various cryptographic 5 * algorithms in a highly modular and flexible manner. 6 * 7 * The library is free for all purposes without any express 8 * guarantee it works. 9 */ 10 11 /** 12 @file rc6.c 13 LTC_RC6 code by Tom St Denis 14 */ 15 #include "tomcrypt_private.h" 16 17 #ifdef LTC_RC6 18 19 const struct ltc_cipher_descriptor rc6_desc = 20 { 21 "rc6", 22 3, 23 8, 128, 16, 20, 24 &rc6_setup, 25 &rc6_ecb_encrypt, 26 &rc6_ecb_decrypt, 27 &rc6_test, 28 &rc6_done, 29 &rc6_keysize, 30 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL 31 }; 32 33 static const ulong32 stab[44] = { 34 0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL, 35 0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL, 36 0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL, 37 0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL, 38 0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL, 39 0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL }; 40 41 /** 42 Initialize the LTC_RC6 block cipher 43 @param key The symmetric key you wish to pass 44 @param keylen The key length in bytes 45 @param num_rounds The number of rounds desired (0 for default) 46 @param skey The key in as scheduled by this function. 47 @return CRYPT_OK if successful 48 */ 49 #ifdef LTC_CLEAN_STACK 50 static int _rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) 51 #else 52 int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) 53 #endif 54 { 55 ulong32 L[64], S[50], A, B, i, j, v, s, l; 56 57 LTC_ARGCHK(key != NULL); 58 LTC_ARGCHK(skey != NULL); 59 60 /* test parameters */ 61 if (num_rounds != 0 && num_rounds != 20) { 62 return CRYPT_INVALID_ROUNDS; 63 } 64 65 /* key must be between 64 and 1024 bits */ 66 if (keylen < 8 || keylen > 128) { 67 return CRYPT_INVALID_KEYSIZE; 68 } 69 70 /* copy the key into the L array */ 71 for (A = i = j = 0; i < (ulong32)keylen; ) { 72 A = (A << 8) | ((ulong32)(key[i++] & 255)); 73 if (!(i & 3)) { 74 L[j++] = BSWAP(A); 75 A = 0; 76 } 77 } 78 79 /* handle odd sized keys */ 80 if (keylen & 3) { 81 A <<= (8 * (4 - (keylen&3))); 82 L[j++] = BSWAP(A); 83 } 84 85 /* setup the S array */ 86 XMEMCPY(S, stab, 44 * sizeof(stab[0])); 87 88 /* mix buffer */ 89 s = 3 * MAX(44, j); 90 l = j; 91 for (A = B = i = j = v = 0; v < s; v++) { 92 A = S[i] = ROLc(S[i] + A + B, 3); 93 B = L[j] = ROL(L[j] + A + B, (A+B)); 94 if (++i == 44) { i = 0; } 95 if (++j == l) { j = 0; } 96 } 97 98 /* copy to key */ 99 for (i = 0; i < 44; i++) { 100 skey->rc6.K[i] = S[i]; 101 } 102 return CRYPT_OK; 103 } 104 105 #ifdef LTC_CLEAN_STACK 106 int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) 107 { 108 int x; 109 x = _rc6_setup(key, keylen, num_rounds, skey); 110 burn_stack(sizeof(ulong32) * 122); 111 return x; 112 } 113 #endif 114 115 /** 116 Encrypts a block of text with LTC_RC6 117 @param pt The input plaintext (16 bytes) 118 @param ct The output ciphertext (16 bytes) 119 @param skey The key as scheduled 120 */ 121 #ifdef LTC_CLEAN_STACK 122 static int _rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey) 123 #else 124 int rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey) 125 #endif 126 { 127 ulong32 a,b,c,d,t,u; 128 const ulong32 *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, const 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 LTC_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, const symmetric_key *skey) 178 #else 179 int rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey) 180 #endif 181 { 182 ulong32 a,b,c,d,t,u; 183 const ulong32 *K; 184 int r; 185 186 LTC_ARGCHK(skey != NULL); 187 LTC_ARGCHK(pt != NULL); 188 LTC_ARGCHK(ct != NULL); 189 190 LOAD32L(a,&ct[0]);LOAD32L(b,&ct[4]);LOAD32L(c,&ct[8]);LOAD32L(d,&ct[12]); 191 a -= skey->rc6.K[42]; 192 c -= skey->rc6.K[43]; 193 194 #define RND(a,b,c,d) \ 195 t = (b * (b + b + 1)); t = ROLc(t, 5); \ 196 u = (d * (d + d + 1)); u = ROLc(u, 5); \ 197 c = ROR(c - K[1], t) ^ u; \ 198 a = ROR(a - K[0], u) ^ t; K -= 2; 199 200 K = skey->rc6.K + 40; 201 202 for (r = 0; r < 20; r += 4) { 203 RND(d,a,b,c); 204 RND(c,d,a,b); 205 RND(b,c,d,a); 206 RND(a,b,c,d); 207 } 208 209 #undef RND 210 211 b -= skey->rc6.K[0]; 212 d -= skey->rc6.K[1]; 213 STORE32L(a,&pt[0]);STORE32L(b,&pt[4]);STORE32L(c,&pt[8]);STORE32L(d,&pt[12]); 214 215 return CRYPT_OK; 216 } 217 218 #ifdef LTC_CLEAN_STACK 219 int rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey) 220 { 221 int err = _rc6_ecb_decrypt(ct, pt, skey); 222 burn_stack(sizeof(ulong32) * 6 + sizeof(int)); 223 return err; 224 } 225 #endif 226 227 /** 228 Performs a self-test of the LTC_RC6 block cipher 229 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled 230 */ 231 int rc6_test(void) 232 { 233 #ifndef LTC_TEST 234 return CRYPT_NOP; 235 #else 236 static const struct { 237 int keylen; 238 unsigned char key[32], pt[16], ct[16]; 239 } tests[] = { 240 { 241 16, 242 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 243 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 244 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 245 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, 246 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 247 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, 248 { 0x52, 0x4e, 0x19, 0x2f, 0x47, 0x15, 0xc6, 0x23, 249 0x1f, 0x51, 0xf6, 0x36, 0x7e, 0xa4, 0x3f, 0x18 } 250 }, 251 { 252 24, 253 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 254 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 255 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0, 256 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, 257 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 258 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, 259 { 0x68, 0x83, 0x29, 0xd0, 0x19, 0xe5, 0x05, 0x04, 260 0x1e, 0x52, 0xe9, 0x2a, 0xf9, 0x52, 0x91, 0xd4 } 261 }, 262 { 263 32, 264 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 265 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 266 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0, 267 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe }, 268 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, 269 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, 270 { 0xc8, 0x24, 0x18, 0x16, 0xf0, 0xd7, 0xe4, 0x89, 271 0x20, 0xad, 0x16, 0xa1, 0x67, 0x4e, 0x5d, 0x48 } 272 } 273 }; 274 unsigned char tmp[2][16]; 275 int x, y, err; 276 symmetric_key key; 277 278 for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) { 279 /* setup key */ 280 if ((err = rc6_setup(tests[x].key, tests[x].keylen, 0, &key)) != CRYPT_OK) { 281 return err; 282 } 283 284 /* encrypt and decrypt */ 285 rc6_ecb_encrypt(tests[x].pt, tmp[0], &key); 286 rc6_ecb_decrypt(tmp[0], tmp[1], &key); 287 288 /* compare */ 289 if (compare_testvector(tmp[0], 16, tests[x].ct, 16, "RC6 Encrypt", x) || 290 compare_testvector(tmp[1], 16, tests[x].pt, 16, "RC6 Decrypt", x)) { 291 return CRYPT_FAIL_TESTVECTOR; 292 } 293 294 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */ 295 for (y = 0; y < 16; y++) tmp[0][y] = 0; 296 for (y = 0; y < 1000; y++) rc6_ecb_encrypt(tmp[0], tmp[0], &key); 297 for (y = 0; y < 1000; y++) rc6_ecb_decrypt(tmp[0], tmp[0], &key); 298 for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR; 299 } 300 return CRYPT_OK; 301 #endif 302 } 303 304 /** Terminate the context 305 @param skey The scheduled key 306 */ 307 void rc6_done(symmetric_key *skey) 308 { 309 LTC_UNUSED_PARAM(skey); 310 } 311 312 /** 313 Gets suitable key size 314 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable. 315 @return CRYPT_OK if the input key size is acceptable. 316 */ 317 int rc6_keysize(int *keysize) 318 { 319 LTC_ARGCHK(keysize != NULL); 320 if (*keysize < 8) { 321 return CRYPT_INVALID_KEYSIZE; 322 } 323 if (*keysize > 128) { 324 *keysize = 128; 325 } 326 return CRYPT_OK; 327 } 328 329 #endif /*LTC_RC6*/ 330 331 332 333 /* ref: $Format:%D$ */ 334 /* git commit: $Format:%H$ */ 335 /* commit time: $Format:%ai$ */ 336