cts128.c revision 279264
1/* ==================================================================== 2 * Copyright (c) 2008 The OpenSSL Project. All rights reserved. 3 * 4 * Rights for redistribution and usage in source and binary 5 * forms are granted according to the OpenSSL license. 6 */ 7 8#include <openssl/crypto.h> 9#include "modes_lcl.h" 10#include <string.h> 11 12#ifndef MODES_DEBUG 13# ifndef NDEBUG 14# define NDEBUG 15# endif 16#endif 17#include <assert.h> 18 19/* 20 * Trouble with Ciphertext Stealing, CTS, mode is that there is no 21 * common official specification, but couple of cipher/application 22 * specific ones: RFC2040 and RFC3962. Then there is 'Proposal to 23 * Extend CBC Mode By "Ciphertext Stealing"' at NIST site, which 24 * deviates from mentioned RFCs. Most notably it allows input to be 25 * of block length and it doesn't flip the order of the last two 26 * blocks. CTS is being discussed even in ECB context, but it's not 27 * adopted for any known application. This implementation provides 28 * two interfaces: one compliant with above mentioned RFCs and one 29 * compliant with the NIST proposal, both extending CBC mode. 30 */ 31 32size_t CRYPTO_cts128_encrypt_block(const unsigned char *in, unsigned char *out, 33 size_t len, const void *key, 34 unsigned char ivec[16], block128_f block) 35{ size_t residue, n; 36 37 assert (in && out && key && ivec); 38 39 if (len <= 16) return 0; 40 41 if ((residue=len%16) == 0) residue = 16; 42 43 len -= residue; 44 45 CRYPTO_cbc128_encrypt(in,out,len,key,ivec,block); 46 47 in += len; 48 out += len; 49 50 for (n=0; n<residue; ++n) 51 ivec[n] ^= in[n]; 52 (*block)(ivec,ivec,key); 53 memcpy(out,out-16,residue); 54 memcpy(out-16,ivec,16); 55 56 return len+residue; 57} 58 59size_t CRYPTO_nistcts128_encrypt_block(const unsigned char *in, unsigned char *out, 60 size_t len, const void *key, 61 unsigned char ivec[16], block128_f block) 62{ size_t residue, n; 63 64 assert (in && out && key && ivec); 65 66 if (len < 16) return 0; 67 68 residue=len%16; 69 70 len -= residue; 71 72 CRYPTO_cbc128_encrypt(in,out,len,key,ivec,block); 73 74 if (residue==0) return len; 75 76 in += len; 77 out += len; 78 79 for (n=0; n<residue; ++n) 80 ivec[n] ^= in[n]; 81 (*block)(ivec,ivec,key); 82 memcpy(out-16+residue,ivec,16); 83 84 return len+residue; 85} 86 87size_t CRYPTO_cts128_encrypt(const unsigned char *in, unsigned char *out, 88 size_t len, const void *key, 89 unsigned char ivec[16], cbc128_f cbc) 90{ size_t residue; 91 union { size_t align; unsigned char c[16]; } tmp; 92 93 assert (in && out && key && ivec); 94 95 if (len <= 16) return 0; 96 97 if ((residue=len%16) == 0) residue = 16; 98 99 len -= residue; 100 101 (*cbc)(in,out,len,key,ivec,1); 102 103 in += len; 104 out += len; 105 106#if defined(CBC_HANDLES_TRUNCATED_IO) 107 memcpy(tmp.c,out-16,16); 108 (*cbc)(in,out-16,residue,key,ivec,1); 109 memcpy(out,tmp.c,residue); 110#else 111 memset(tmp.c,0,sizeof(tmp)); 112 memcpy(tmp.c,in,residue); 113 memcpy(out,out-16,residue); 114 (*cbc)(tmp.c,out-16,16,key,ivec,1); 115#endif 116 return len+residue; 117} 118 119size_t CRYPTO_nistcts128_encrypt(const unsigned char *in, unsigned char *out, 120 size_t len, const void *key, 121 unsigned char ivec[16], cbc128_f cbc) 122{ size_t residue; 123 union { size_t align; unsigned char c[16]; } tmp; 124 125 assert (in && out && key && ivec); 126 127 if (len < 16) return 0; 128 129 residue=len%16; 130 131 len -= residue; 132 133 (*cbc)(in,out,len,key,ivec,1); 134 135 if (residue==0) return len; 136 137 in += len; 138 out += len; 139 140#if defined(CBC_HANDLES_TRUNCATED_IO) 141 (*cbc)(in,out-16+residue,residue,key,ivec,1); 142#else 143 memset(tmp.c,0,sizeof(tmp)); 144 memcpy(tmp.c,in,residue); 145 (*cbc)(tmp.c,out-16+residue,16,key,ivec,1); 146#endif 147 return len+residue; 148} 149 150size_t CRYPTO_cts128_decrypt_block(const unsigned char *in, unsigned char *out, 151 size_t len, const void *key, 152 unsigned char ivec[16], block128_f block) 153{ size_t residue, n; 154 union { size_t align; unsigned char c[32]; } tmp; 155 156 assert (in && out && key && ivec); 157 158 if (len<=16) return 0; 159 160 if ((residue=len%16) == 0) residue = 16; 161 162 len -= 16+residue; 163 164 if (len) { 165 CRYPTO_cbc128_decrypt(in,out,len,key,ivec,block); 166 in += len; 167 out += len; 168 } 169 170 (*block)(in,tmp.c+16,key); 171 172 memcpy(tmp.c,tmp.c+16,16); 173 memcpy(tmp.c,in+16,residue); 174 (*block)(tmp.c,tmp.c,key); 175 176 for(n=0; n<16; ++n) { 177 unsigned char c = in[n]; 178 out[n] = tmp.c[n] ^ ivec[n]; 179 ivec[n] = c; 180 } 181 for(residue+=16; n<residue; ++n) 182 out[n] = tmp.c[n] ^ in[n]; 183 184 return 16+len+residue; 185} 186 187size_t CRYPTO_nistcts128_decrypt_block(const unsigned char *in, unsigned char *out, 188 size_t len, const void *key, 189 unsigned char ivec[16], block128_f block) 190{ size_t residue, n; 191 union { size_t align; unsigned char c[32]; } tmp; 192 193 assert (in && out && key && ivec); 194 195 if (len<16) return 0; 196 197 residue=len%16; 198 199 if (residue==0) { 200 CRYPTO_cbc128_decrypt(in,out,len,key,ivec,block); 201 return len; 202 } 203 204 len -= 16+residue; 205 206 if (len) { 207 CRYPTO_cbc128_decrypt(in,out,len,key,ivec,block); 208 in += len; 209 out += len; 210 } 211 212 (*block)(in+residue,tmp.c+16,key); 213 214 memcpy(tmp.c,tmp.c+16,16); 215 memcpy(tmp.c,in,residue); 216 (*block)(tmp.c,tmp.c,key); 217 218 for(n=0; n<16; ++n) { 219 unsigned char c = in[n]; 220 out[n] = tmp.c[n] ^ ivec[n]; 221 ivec[n] = in[n+residue]; 222 tmp.c[n] = c; 223 } 224 for(residue+=16; n<residue; ++n) 225 out[n] = tmp.c[n] ^ tmp.c[n-16]; 226 227 return 16+len+residue; 228} 229 230size_t CRYPTO_cts128_decrypt(const unsigned char *in, unsigned char *out, 231 size_t len, const void *key, 232 unsigned char ivec[16], cbc128_f cbc) 233{ size_t residue; 234 union { size_t align; unsigned char c[32]; } tmp; 235 236 assert (in && out && key && ivec); 237 238 if (len<=16) return 0; 239 240 if ((residue=len%16) == 0) residue = 16; 241 242 len -= 16+residue; 243 244 if (len) { 245 (*cbc)(in,out,len,key,ivec,0); 246 in += len; 247 out += len; 248 } 249 250 memset(tmp.c,0,sizeof(tmp)); 251 /* this places in[16] at &tmp.c[16] and decrypted block at &tmp.c[0] */ 252 (*cbc)(in,tmp.c,16,key,tmp.c+16,0); 253 254 memcpy(tmp.c,in+16,residue); 255#if defined(CBC_HANDLES_TRUNCATED_IO) 256 (*cbc)(tmp.c,out,16+residue,key,ivec,0); 257#else 258 (*cbc)(tmp.c,tmp.c,32,key,ivec,0); 259 memcpy(out,tmp.c,16+residue); 260#endif 261 return 16+len+residue; 262} 263 264size_t CRYPTO_nistcts128_decrypt(const unsigned char *in, unsigned char *out, 265 size_t len, const void *key, 266 unsigned char ivec[16], cbc128_f cbc) 267{ size_t residue; 268 union { size_t align; unsigned char c[32]; } tmp; 269 270 assert (in && out && key && ivec); 271 272 if (len<16) return 0; 273 274 residue=len%16; 275 276 if (residue==0) { 277 (*cbc)(in,out,len,key,ivec,0); 278 return len; 279 } 280 281 len -= 16+residue; 282 283 if (len) { 284 (*cbc)(in,out,len,key,ivec,0); 285 in += len; 286 out += len; 287 } 288 289 memset(tmp.c,0,sizeof(tmp)); 290 /* this places in[16] at &tmp.c[16] and decrypted block at &tmp.c[0] */ 291 (*cbc)(in+residue,tmp.c,16,key,tmp.c+16,0); 292 293 memcpy(tmp.c,in,residue); 294#if defined(CBC_HANDLES_TRUNCATED_IO) 295 (*cbc)(tmp.c,out,16+residue,key,ivec,0); 296#else 297 (*cbc)(tmp.c,tmp.c,32,key,ivec,0); 298 memcpy(out,tmp.c,16+residue); 299#endif 300 return 16+len+residue; 301} 302 303#if defined(SELFTEST) 304#include <stdio.h> 305#include <openssl/aes.h> 306 307/* test vectors from RFC 3962 */ 308static const unsigned char test_key[16] = "chicken teriyaki"; 309static const unsigned char test_input[64] = 310 "I would like the" " General Gau's C" 311 "hicken, please, " "and wonton soup."; 312static const unsigned char test_iv[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; 313 314static const unsigned char vector_17[17] = 315{0xc6,0x35,0x35,0x68,0xf2,0xbf,0x8c,0xb4, 0xd8,0xa5,0x80,0x36,0x2d,0xa7,0xff,0x7f, 316 0x97}; 317static const unsigned char vector_31[31] = 318{0xfc,0x00,0x78,0x3e,0x0e,0xfd,0xb2,0xc1, 0xd4,0x45,0xd4,0xc8,0xef,0xf7,0xed,0x22, 319 0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5}; 320static const unsigned char vector_32[32] = 321{0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5, 0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5,0xa8, 322 0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84}; 323static const unsigned char vector_47[47] = 324{0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84, 325 0xb3,0xff,0xfd,0x94,0x0c,0x16,0xa1,0x8c, 0x1b,0x55,0x49,0xd2,0xf8,0x38,0x02,0x9e, 326 0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5, 0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5}; 327static const unsigned char vector_48[48] = 328{0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84, 329 0x9d,0xad,0x8b,0xbb,0x96,0xc4,0xcd,0xc0, 0x3b,0xc1,0x03,0xe1,0xa1,0x94,0xbb,0xd8, 330 0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5, 0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5,0xa8}; 331static const unsigned char vector_64[64] = 332{0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84, 333 0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5, 0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5,0xa8, 334 0x48,0x07,0xef,0xe8,0x36,0xee,0x89,0xa5, 0x26,0x73,0x0d,0xbc,0x2f,0x7b,0xc8,0x40, 335 0x9d,0xad,0x8b,0xbb,0x96,0xc4,0xcd,0xc0, 0x3b,0xc1,0x03,0xe1,0xa1,0x94,0xbb,0xd8}; 336 337static AES_KEY encks, decks; 338 339void test_vector(const unsigned char *vector,size_t len) 340{ unsigned char iv[sizeof(test_iv)]; 341 unsigned char cleartext[64],ciphertext[64]; 342 size_t tail; 343 344 printf("vector_%d\n",len); fflush(stdout); 345 346 if ((tail=len%16) == 0) tail = 16; 347 tail += 16; 348 349 /* test block-based encryption */ 350 memcpy(iv,test_iv,sizeof(test_iv)); 351 CRYPTO_cts128_encrypt_block(test_input,ciphertext,len,&encks,iv,(block128_f)AES_encrypt); 352 if (memcmp(ciphertext,vector,len)) 353 fprintf(stderr,"output_%d mismatch\n",len), exit(1); 354 if (memcmp(iv,vector+len-tail,sizeof(iv))) 355 fprintf(stderr,"iv_%d mismatch\n",len), exit(1); 356 357 /* test block-based decryption */ 358 memcpy(iv,test_iv,sizeof(test_iv)); 359 CRYPTO_cts128_decrypt_block(ciphertext,cleartext,len,&decks,iv,(block128_f)AES_decrypt); 360 if (memcmp(cleartext,test_input,len)) 361 fprintf(stderr,"input_%d mismatch\n",len), exit(2); 362 if (memcmp(iv,vector+len-tail,sizeof(iv))) 363 fprintf(stderr,"iv_%d mismatch\n",len), exit(2); 364 365 /* test streamed encryption */ 366 memcpy(iv,test_iv,sizeof(test_iv)); 367 CRYPTO_cts128_encrypt(test_input,ciphertext,len,&encks,iv,(cbc128_f)AES_cbc_encrypt); 368 if (memcmp(ciphertext,vector,len)) 369 fprintf(stderr,"output_%d mismatch\n",len), exit(3); 370 if (memcmp(iv,vector+len-tail,sizeof(iv))) 371 fprintf(stderr,"iv_%d mismatch\n",len), exit(3); 372 373 /* test streamed decryption */ 374 memcpy(iv,test_iv,sizeof(test_iv)); 375 CRYPTO_cts128_decrypt(ciphertext,cleartext,len,&decks,iv,(cbc128_f)AES_cbc_encrypt); 376 if (memcmp(cleartext,test_input,len)) 377 fprintf(stderr,"input_%d mismatch\n",len), exit(4); 378 if (memcmp(iv,vector+len-tail,sizeof(iv))) 379 fprintf(stderr,"iv_%d mismatch\n",len), exit(4); 380} 381 382void test_nistvector(const unsigned char *vector,size_t len) 383{ unsigned char iv[sizeof(test_iv)]; 384 unsigned char cleartext[64],ciphertext[64],nistvector[64]; 385 size_t tail; 386 387 printf("nistvector_%d\n",len); fflush(stdout); 388 389 if ((tail=len%16) == 0) tail = 16; 390 391 len -= 16 + tail; 392 memcpy(nistvector,vector,len); 393 /* flip two last blocks */ 394 memcpy(nistvector+len,vector+len+16,tail); 395 memcpy(nistvector+len+tail,vector+len,16); 396 len += 16 + tail; 397 tail = 16; 398 399 /* test block-based encryption */ 400 memcpy(iv,test_iv,sizeof(test_iv)); 401 CRYPTO_nistcts128_encrypt_block(test_input,ciphertext,len,&encks,iv,(block128_f)AES_encrypt); 402 if (memcmp(ciphertext,nistvector,len)) 403 fprintf(stderr,"output_%d mismatch\n",len), exit(1); 404 if (memcmp(iv,nistvector+len-tail,sizeof(iv))) 405 fprintf(stderr,"iv_%d mismatch\n",len), exit(1); 406 407 /* test block-based decryption */ 408 memcpy(iv,test_iv,sizeof(test_iv)); 409 CRYPTO_nistcts128_decrypt_block(ciphertext,cleartext,len,&decks,iv,(block128_f)AES_decrypt); 410 if (memcmp(cleartext,test_input,len)) 411 fprintf(stderr,"input_%d mismatch\n",len), exit(2); 412 if (memcmp(iv,nistvector+len-tail,sizeof(iv))) 413 fprintf(stderr,"iv_%d mismatch\n",len), exit(2); 414 415 /* test streamed encryption */ 416 memcpy(iv,test_iv,sizeof(test_iv)); 417 CRYPTO_nistcts128_encrypt(test_input,ciphertext,len,&encks,iv,(cbc128_f)AES_cbc_encrypt); 418 if (memcmp(ciphertext,nistvector,len)) 419 fprintf(stderr,"output_%d mismatch\n",len), exit(3); 420 if (memcmp(iv,nistvector+len-tail,sizeof(iv))) 421 fprintf(stderr,"iv_%d mismatch\n",len), exit(3); 422 423 /* test streamed decryption */ 424 memcpy(iv,test_iv,sizeof(test_iv)); 425 CRYPTO_nistcts128_decrypt(ciphertext,cleartext,len,&decks,iv,(cbc128_f)AES_cbc_encrypt); 426 if (memcmp(cleartext,test_input,len)) 427 fprintf(stderr,"input_%d mismatch\n",len), exit(4); 428 if (memcmp(iv,nistvector+len-tail,sizeof(iv))) 429 fprintf(stderr,"iv_%d mismatch\n",len), exit(4); 430} 431 432int main() 433{ 434 AES_set_encrypt_key(test_key,128,&encks); 435 AES_set_decrypt_key(test_key,128,&decks); 436 437 test_vector(vector_17,sizeof(vector_17)); 438 test_vector(vector_31,sizeof(vector_31)); 439 test_vector(vector_32,sizeof(vector_32)); 440 test_vector(vector_47,sizeof(vector_47)); 441 test_vector(vector_48,sizeof(vector_48)); 442 test_vector(vector_64,sizeof(vector_64)); 443 444 test_nistvector(vector_17,sizeof(vector_17)); 445 test_nistvector(vector_31,sizeof(vector_31)); 446 test_nistvector(vector_32,sizeof(vector_32)); 447 test_nistvector(vector_47,sizeof(vector_47)); 448 test_nistvector(vector_48,sizeof(vector_48)); 449 test_nistvector(vector_64,sizeof(vector_64)); 450 451 return 0; 452} 453#endif 454