diff options
Diffstat (limited to '')
| -rw-r--r-- | src/lib/libcrypto/modes/ccm128.c | 441 |
1 files changed, 441 insertions, 0 deletions
diff --git a/src/lib/libcrypto/modes/ccm128.c b/src/lib/libcrypto/modes/ccm128.c new file mode 100644 index 0000000000..c9b35e5b35 --- /dev/null +++ b/src/lib/libcrypto/modes/ccm128.c | |||
| @@ -0,0 +1,441 @@ | |||
| 1 | /* ==================================================================== | ||
| 2 | * Copyright (c) 2011 The OpenSSL Project. All rights reserved. | ||
| 3 | * | ||
| 4 | * Redistribution and use in source and binary forms, with or without | ||
| 5 | * modification, are permitted provided that the following conditions | ||
| 6 | * are met: | ||
| 7 | * | ||
| 8 | * 1. Redistributions of source code must retain the above copyright | ||
| 9 | * notice, this list of conditions and the following disclaimer. | ||
| 10 | * | ||
| 11 | * 2. Redistributions in binary form must reproduce the above copyright | ||
| 12 | * notice, this list of conditions and the following disclaimer in | ||
| 13 | * the documentation and/or other materials provided with the | ||
| 14 | * distribution. | ||
| 15 | * | ||
| 16 | * 3. All advertising materials mentioning features or use of this | ||
| 17 | * software must display the following acknowledgment: | ||
| 18 | * "This product includes software developed by the OpenSSL Project | ||
| 19 | * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | ||
| 20 | * | ||
| 21 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | ||
| 22 | * endorse or promote products derived from this software without | ||
| 23 | * prior written permission. For written permission, please contact | ||
| 24 | * openssl-core@openssl.org. | ||
| 25 | * | ||
| 26 | * 5. Products derived from this software may not be called "OpenSSL" | ||
| 27 | * nor may "OpenSSL" appear in their names without prior written | ||
| 28 | * permission of the OpenSSL Project. | ||
| 29 | * | ||
| 30 | * 6. Redistributions of any form whatsoever must retain the following | ||
| 31 | * acknowledgment: | ||
| 32 | * "This product includes software developed by the OpenSSL Project | ||
| 33 | * for use in the OpenSSL Toolkit (http://www.openssl.org/)" | ||
| 34 | * | ||
| 35 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | ||
| 36 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
| 37 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | ||
| 38 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | ||
| 39 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | ||
| 40 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | ||
| 41 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | ||
| 42 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
| 43 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | ||
| 44 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | ||
| 45 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | ||
| 46 | * OF THE POSSIBILITY OF SUCH DAMAGE. | ||
| 47 | * ==================================================================== | ||
| 48 | */ | ||
| 49 | |||
| 50 | #include <openssl/crypto.h> | ||
| 51 | #include "modes_lcl.h" | ||
| 52 | #include <string.h> | ||
| 53 | |||
| 54 | #ifndef MODES_DEBUG | ||
| 55 | # ifndef NDEBUG | ||
| 56 | # define NDEBUG | ||
| 57 | # endif | ||
| 58 | #endif | ||
| 59 | #include <assert.h> | ||
| 60 | |||
| 61 | /* First you setup M and L parameters and pass the key schedule. | ||
| 62 | * This is called once per session setup... */ | ||
| 63 | void CRYPTO_ccm128_init(CCM128_CONTEXT *ctx, | ||
| 64 | unsigned int M,unsigned int L,void *key,block128_f block) | ||
| 65 | { | ||
| 66 | memset(ctx->nonce.c,0,sizeof(ctx->nonce.c)); | ||
| 67 | ctx->nonce.c[0] = ((u8)(L-1)&7) | (u8)(((M-2)/2)&7)<<3; | ||
| 68 | ctx->blocks = 0; | ||
| 69 | ctx->block = block; | ||
| 70 | ctx->key = key; | ||
| 71 | } | ||
| 72 | |||
| 73 | /* !!! Following interfaces are to be called *once* per packet !!! */ | ||
| 74 | |||
| 75 | /* Then you setup per-message nonce and pass the length of the message */ | ||
| 76 | int CRYPTO_ccm128_setiv(CCM128_CONTEXT *ctx, | ||
| 77 | const unsigned char *nonce,size_t nlen,size_t mlen) | ||
| 78 | { | ||
| 79 | unsigned int L = ctx->nonce.c[0]&7; /* the L parameter */ | ||
| 80 | |||
| 81 | if (nlen<(14-L)) return -1; /* nonce is too short */ | ||
| 82 | |||
| 83 | if (sizeof(mlen)==8 && L>=3) { | ||
| 84 | ctx->nonce.c[8] = (u8)(mlen>>(56%(sizeof(mlen)*8))); | ||
| 85 | ctx->nonce.c[9] = (u8)(mlen>>(48%(sizeof(mlen)*8))); | ||
| 86 | ctx->nonce.c[10] = (u8)(mlen>>(40%(sizeof(mlen)*8))); | ||
| 87 | ctx->nonce.c[11] = (u8)(mlen>>(32%(sizeof(mlen)*8))); | ||
| 88 | } | ||
| 89 | else | ||
| 90 | *(u32*)(&ctx->nonce.c[8]) = 0; | ||
| 91 | |||
| 92 | ctx->nonce.c[12] = (u8)(mlen>>24); | ||
| 93 | ctx->nonce.c[13] = (u8)(mlen>>16); | ||
| 94 | ctx->nonce.c[14] = (u8)(mlen>>8); | ||
| 95 | ctx->nonce.c[15] = (u8)mlen; | ||
| 96 | |||
| 97 | ctx->nonce.c[0] &= ~0x40; /* clear Adata flag */ | ||
| 98 | memcpy(&ctx->nonce.c[1],nonce,14-L); | ||
| 99 | |||
| 100 | return 0; | ||
| 101 | } | ||
| 102 | |||
| 103 | /* Then you pass additional authentication data, this is optional */ | ||
| 104 | void CRYPTO_ccm128_aad(CCM128_CONTEXT *ctx, | ||
| 105 | const unsigned char *aad,size_t alen) | ||
| 106 | { unsigned int i; | ||
| 107 | block128_f block = ctx->block; | ||
| 108 | |||
| 109 | if (alen==0) return; | ||
| 110 | |||
| 111 | ctx->nonce.c[0] |= 0x40; /* set Adata flag */ | ||
| 112 | (*block)(ctx->nonce.c,ctx->cmac.c,ctx->key), | ||
| 113 | ctx->blocks++; | ||
| 114 | |||
| 115 | if (alen<(0x10000-0x100)) { | ||
| 116 | ctx->cmac.c[0] ^= (u8)(alen>>8); | ||
| 117 | ctx->cmac.c[1] ^= (u8)alen; | ||
| 118 | i=2; | ||
| 119 | } | ||
| 120 | else if (sizeof(alen)==8 && alen>=(size_t)1<<(32%(sizeof(alen)*8))) { | ||
| 121 | ctx->cmac.c[0] ^= 0xFF; | ||
| 122 | ctx->cmac.c[1] ^= 0xFF; | ||
| 123 | ctx->cmac.c[2] ^= (u8)(alen>>(56%(sizeof(alen)*8))); | ||
| 124 | ctx->cmac.c[3] ^= (u8)(alen>>(48%(sizeof(alen)*8))); | ||
| 125 | ctx->cmac.c[4] ^= (u8)(alen>>(40%(sizeof(alen)*8))); | ||
| 126 | ctx->cmac.c[5] ^= (u8)(alen>>(32%(sizeof(alen)*8))); | ||
| 127 | ctx->cmac.c[6] ^= (u8)(alen>>24); | ||
| 128 | ctx->cmac.c[7] ^= (u8)(alen>>16); | ||
| 129 | ctx->cmac.c[8] ^= (u8)(alen>>8); | ||
| 130 | ctx->cmac.c[9] ^= (u8)alen; | ||
| 131 | i=10; | ||
| 132 | } | ||
| 133 | else { | ||
| 134 | ctx->cmac.c[0] ^= 0xFF; | ||
| 135 | ctx->cmac.c[1] ^= 0xFE; | ||
| 136 | ctx->cmac.c[2] ^= (u8)(alen>>24); | ||
| 137 | ctx->cmac.c[3] ^= (u8)(alen>>16); | ||
| 138 | ctx->cmac.c[4] ^= (u8)(alen>>8); | ||
| 139 | ctx->cmac.c[5] ^= (u8)alen; | ||
| 140 | i=6; | ||
| 141 | } | ||
| 142 | |||
| 143 | do { | ||
| 144 | for(;i<16 && alen;++i,++aad,--alen) | ||
| 145 | ctx->cmac.c[i] ^= *aad; | ||
| 146 | (*block)(ctx->cmac.c,ctx->cmac.c,ctx->key), | ||
| 147 | ctx->blocks++; | ||
| 148 | i=0; | ||
| 149 | } while (alen); | ||
| 150 | } | ||
| 151 | |||
| 152 | /* Finally you encrypt or decrypt the message */ | ||
| 153 | |||
| 154 | /* counter part of nonce may not be larger than L*8 bits, | ||
| 155 | * L is not larger than 8, therefore 64-bit counter... */ | ||
| 156 | static void ctr64_inc(unsigned char *counter) { | ||
| 157 | unsigned int n=8; | ||
| 158 | u8 c; | ||
| 159 | |||
| 160 | counter += 8; | ||
| 161 | do { | ||
| 162 | --n; | ||
| 163 | c = counter[n]; | ||
| 164 | ++c; | ||
| 165 | counter[n] = c; | ||
| 166 | if (c) return; | ||
| 167 | } while (n); | ||
| 168 | } | ||
| 169 | |||
| 170 | int CRYPTO_ccm128_encrypt(CCM128_CONTEXT *ctx, | ||
| 171 | const unsigned char *inp, unsigned char *out, | ||
| 172 | size_t len) | ||
| 173 | { | ||
| 174 | size_t n; | ||
| 175 | unsigned int i,L; | ||
| 176 | unsigned char flags0 = ctx->nonce.c[0]; | ||
| 177 | block128_f block = ctx->block; | ||
| 178 | void * key = ctx->key; | ||
| 179 | union { u64 u[2]; u8 c[16]; } scratch; | ||
| 180 | |||
| 181 | if (!(flags0&0x40)) | ||
| 182 | (*block)(ctx->nonce.c,ctx->cmac.c,key), | ||
| 183 | ctx->blocks++; | ||
| 184 | |||
| 185 | ctx->nonce.c[0] = L = flags0&7; | ||
| 186 | for (n=0,i=15-L;i<15;++i) { | ||
| 187 | n |= ctx->nonce.c[i]; | ||
| 188 | ctx->nonce.c[i]=0; | ||
| 189 | n <<= 8; | ||
| 190 | } | ||
| 191 | n |= ctx->nonce.c[15]; /* reconstructed length */ | ||
| 192 | ctx->nonce.c[15]=1; | ||
| 193 | |||
| 194 | if (n!=len) return -1; /* length mismatch */ | ||
| 195 | |||
| 196 | ctx->blocks += ((len+15)>>3)|1; | ||
| 197 | if (ctx->blocks > (U64(1)<<61)) return -2; /* too much data */ | ||
| 198 | |||
| 199 | while (len>=16) { | ||
| 200 | #if defined(STRICT_ALIGNMENT) | ||
| 201 | union { u64 u[2]; u8 c[16]; } temp; | ||
| 202 | |||
| 203 | memcpy (temp.c,inp,16); | ||
| 204 | ctx->cmac.u[0] ^= temp.u[0]; | ||
| 205 | ctx->cmac.u[1] ^= temp.u[1]; | ||
| 206 | #else | ||
| 207 | ctx->cmac.u[0] ^= ((u64*)inp)[0]; | ||
| 208 | ctx->cmac.u[1] ^= ((u64*)inp)[1]; | ||
| 209 | #endif | ||
| 210 | (*block)(ctx->cmac.c,ctx->cmac.c,key); | ||
| 211 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 212 | ctr64_inc(ctx->nonce.c); | ||
| 213 | #if defined(STRICT_ALIGNMENT) | ||
| 214 | temp.u[0] ^= scratch.u[0]; | ||
| 215 | temp.u[1] ^= scratch.u[1]; | ||
| 216 | memcpy(out,temp.c,16); | ||
| 217 | #else | ||
| 218 | ((u64*)out)[0] = scratch.u[0]^((u64*)inp)[0]; | ||
| 219 | ((u64*)out)[1] = scratch.u[1]^((u64*)inp)[1]; | ||
| 220 | #endif | ||
| 221 | inp += 16; | ||
| 222 | out += 16; | ||
| 223 | len -= 16; | ||
| 224 | } | ||
| 225 | |||
| 226 | if (len) { | ||
| 227 | for (i=0; i<len; ++i) ctx->cmac.c[i] ^= inp[i]; | ||
| 228 | (*block)(ctx->cmac.c,ctx->cmac.c,key); | ||
| 229 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 230 | for (i=0; i<len; ++i) out[i] = scratch.c[i]^inp[i]; | ||
| 231 | } | ||
| 232 | |||
| 233 | for (i=15-L;i<16;++i) | ||
| 234 | ctx->nonce.c[i]=0; | ||
| 235 | |||
| 236 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 237 | ctx->cmac.u[0] ^= scratch.u[0]; | ||
| 238 | ctx->cmac.u[1] ^= scratch.u[1]; | ||
| 239 | |||
| 240 | ctx->nonce.c[0] = flags0; | ||
| 241 | |||
| 242 | return 0; | ||
| 243 | } | ||
| 244 | |||
| 245 | int CRYPTO_ccm128_decrypt(CCM128_CONTEXT *ctx, | ||
| 246 | const unsigned char *inp, unsigned char *out, | ||
| 247 | size_t len) | ||
| 248 | { | ||
| 249 | size_t n; | ||
| 250 | unsigned int i,L; | ||
| 251 | unsigned char flags0 = ctx->nonce.c[0]; | ||
| 252 | block128_f block = ctx->block; | ||
| 253 | void * key = ctx->key; | ||
| 254 | union { u64 u[2]; u8 c[16]; } scratch; | ||
| 255 | |||
| 256 | if (!(flags0&0x40)) | ||
| 257 | (*block)(ctx->nonce.c,ctx->cmac.c,key); | ||
| 258 | |||
| 259 | ctx->nonce.c[0] = L = flags0&7; | ||
| 260 | for (n=0,i=15-L;i<15;++i) { | ||
| 261 | n |= ctx->nonce.c[i]; | ||
| 262 | ctx->nonce.c[i]=0; | ||
| 263 | n <<= 8; | ||
| 264 | } | ||
| 265 | n |= ctx->nonce.c[15]; /* reconstructed length */ | ||
| 266 | ctx->nonce.c[15]=1; | ||
| 267 | |||
| 268 | if (n!=len) return -1; | ||
| 269 | |||
| 270 | while (len>=16) { | ||
| 271 | #if defined(STRICT_ALIGNMENT) | ||
| 272 | union { u64 u[2]; u8 c[16]; } temp; | ||
| 273 | #endif | ||
| 274 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 275 | ctr64_inc(ctx->nonce.c); | ||
| 276 | #if defined(STRICT_ALIGNMENT) | ||
| 277 | memcpy (temp.c,inp,16); | ||
| 278 | ctx->cmac.u[0] ^= (scratch.u[0] ^= temp.u[0]); | ||
| 279 | ctx->cmac.u[1] ^= (scratch.u[1] ^= temp.u[1]); | ||
| 280 | memcpy (out,scratch.c,16); | ||
| 281 | #else | ||
| 282 | ctx->cmac.u[0] ^= (((u64*)out)[0] = scratch.u[0]^((u64*)inp)[0]); | ||
| 283 | ctx->cmac.u[1] ^= (((u64*)out)[1] = scratch.u[1]^((u64*)inp)[1]); | ||
| 284 | #endif | ||
| 285 | (*block)(ctx->cmac.c,ctx->cmac.c,key); | ||
| 286 | |||
| 287 | inp += 16; | ||
| 288 | out += 16; | ||
| 289 | len -= 16; | ||
| 290 | } | ||
| 291 | |||
| 292 | if (len) { | ||
| 293 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 294 | for (i=0; i<len; ++i) | ||
| 295 | ctx->cmac.c[i] ^= (out[i] = scratch.c[i]^inp[i]); | ||
| 296 | (*block)(ctx->cmac.c,ctx->cmac.c,key); | ||
| 297 | } | ||
| 298 | |||
| 299 | for (i=15-L;i<16;++i) | ||
| 300 | ctx->nonce.c[i]=0; | ||
| 301 | |||
| 302 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 303 | ctx->cmac.u[0] ^= scratch.u[0]; | ||
| 304 | ctx->cmac.u[1] ^= scratch.u[1]; | ||
| 305 | |||
| 306 | ctx->nonce.c[0] = flags0; | ||
| 307 | |||
| 308 | return 0; | ||
| 309 | } | ||
| 310 | |||
| 311 | static void ctr64_add (unsigned char *counter,size_t inc) | ||
| 312 | { size_t n=8, val=0; | ||
| 313 | |||
| 314 | counter += 8; | ||
| 315 | do { | ||
| 316 | --n; | ||
| 317 | val += counter[n] + (inc&0xff); | ||
| 318 | counter[n] = (unsigned char)val; | ||
| 319 | val >>= 8; /* carry bit */ | ||
| 320 | inc >>= 8; | ||
| 321 | } while(n && (inc || val)); | ||
| 322 | } | ||
| 323 | |||
| 324 | int CRYPTO_ccm128_encrypt_ccm64(CCM128_CONTEXT *ctx, | ||
| 325 | const unsigned char *inp, unsigned char *out, | ||
| 326 | size_t len,ccm128_f stream) | ||
| 327 | { | ||
| 328 | size_t n; | ||
| 329 | unsigned int i,L; | ||
| 330 | unsigned char flags0 = ctx->nonce.c[0]; | ||
| 331 | block128_f block = ctx->block; | ||
| 332 | void * key = ctx->key; | ||
| 333 | union { u64 u[2]; u8 c[16]; } scratch; | ||
| 334 | |||
| 335 | if (!(flags0&0x40)) | ||
| 336 | (*block)(ctx->nonce.c,ctx->cmac.c,key), | ||
| 337 | ctx->blocks++; | ||
| 338 | |||
| 339 | ctx->nonce.c[0] = L = flags0&7; | ||
| 340 | for (n=0,i=15-L;i<15;++i) { | ||
| 341 | n |= ctx->nonce.c[i]; | ||
| 342 | ctx->nonce.c[i]=0; | ||
| 343 | n <<= 8; | ||
| 344 | } | ||
| 345 | n |= ctx->nonce.c[15]; /* reconstructed length */ | ||
| 346 | ctx->nonce.c[15]=1; | ||
| 347 | |||
| 348 | if (n!=len) return -1; /* length mismatch */ | ||
| 349 | |||
| 350 | ctx->blocks += ((len+15)>>3)|1; | ||
| 351 | if (ctx->blocks > (U64(1)<<61)) return -2; /* too much data */ | ||
| 352 | |||
| 353 | if ((n=len/16)) { | ||
| 354 | (*stream)(inp,out,n,key,ctx->nonce.c,ctx->cmac.c); | ||
| 355 | n *= 16; | ||
| 356 | inp += n; | ||
| 357 | out += n; | ||
| 358 | len -= n; | ||
| 359 | if (len) ctr64_add(ctx->nonce.c,n/16); | ||
| 360 | } | ||
| 361 | |||
| 362 | if (len) { | ||
| 363 | for (i=0; i<len; ++i) ctx->cmac.c[i] ^= inp[i]; | ||
| 364 | (*block)(ctx->cmac.c,ctx->cmac.c,key); | ||
| 365 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 366 | for (i=0; i<len; ++i) out[i] = scratch.c[i]^inp[i]; | ||
| 367 | } | ||
| 368 | |||
| 369 | for (i=15-L;i<16;++i) | ||
| 370 | ctx->nonce.c[i]=0; | ||
| 371 | |||
| 372 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 373 | ctx->cmac.u[0] ^= scratch.u[0]; | ||
| 374 | ctx->cmac.u[1] ^= scratch.u[1]; | ||
| 375 | |||
| 376 | ctx->nonce.c[0] = flags0; | ||
| 377 | |||
| 378 | return 0; | ||
| 379 | } | ||
| 380 | |||
| 381 | int CRYPTO_ccm128_decrypt_ccm64(CCM128_CONTEXT *ctx, | ||
| 382 | const unsigned char *inp, unsigned char *out, | ||
| 383 | size_t len,ccm128_f stream) | ||
| 384 | { | ||
| 385 | size_t n; | ||
| 386 | unsigned int i,L; | ||
| 387 | unsigned char flags0 = ctx->nonce.c[0]; | ||
| 388 | block128_f block = ctx->block; | ||
| 389 | void * key = ctx->key; | ||
| 390 | union { u64 u[2]; u8 c[16]; } scratch; | ||
| 391 | |||
| 392 | if (!(flags0&0x40)) | ||
| 393 | (*block)(ctx->nonce.c,ctx->cmac.c,key); | ||
| 394 | |||
| 395 | ctx->nonce.c[0] = L = flags0&7; | ||
| 396 | for (n=0,i=15-L;i<15;++i) { | ||
| 397 | n |= ctx->nonce.c[i]; | ||
| 398 | ctx->nonce.c[i]=0; | ||
| 399 | n <<= 8; | ||
| 400 | } | ||
| 401 | n |= ctx->nonce.c[15]; /* reconstructed length */ | ||
| 402 | ctx->nonce.c[15]=1; | ||
| 403 | |||
| 404 | if (n!=len) return -1; | ||
| 405 | |||
| 406 | if ((n=len/16)) { | ||
| 407 | (*stream)(inp,out,n,key,ctx->nonce.c,ctx->cmac.c); | ||
| 408 | n *= 16; | ||
| 409 | inp += n; | ||
| 410 | out += n; | ||
| 411 | len -= n; | ||
| 412 | if (len) ctr64_add(ctx->nonce.c,n/16); | ||
| 413 | } | ||
| 414 | |||
| 415 | if (len) { | ||
| 416 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 417 | for (i=0; i<len; ++i) | ||
| 418 | ctx->cmac.c[i] ^= (out[i] = scratch.c[i]^inp[i]); | ||
| 419 | (*block)(ctx->cmac.c,ctx->cmac.c,key); | ||
| 420 | } | ||
| 421 | |||
| 422 | for (i=15-L;i<16;++i) | ||
| 423 | ctx->nonce.c[i]=0; | ||
| 424 | |||
| 425 | (*block)(ctx->nonce.c,scratch.c,key); | ||
| 426 | ctx->cmac.u[0] ^= scratch.u[0]; | ||
| 427 | ctx->cmac.u[1] ^= scratch.u[1]; | ||
| 428 | |||
| 429 | ctx->nonce.c[0] = flags0; | ||
| 430 | |||
| 431 | return 0; | ||
| 432 | } | ||
| 433 | |||
| 434 | size_t CRYPTO_ccm128_tag(CCM128_CONTEXT *ctx,unsigned char *tag,size_t len) | ||
| 435 | { unsigned int M = (ctx->nonce.c[0]>>3)&7; /* the M parameter */ | ||
| 436 | |||
| 437 | M *= 2; M += 2; | ||
| 438 | if (len<M) return 0; | ||
| 439 | memcpy(tag,ctx->cmac.c,M); | ||
| 440 | return M; | ||
| 441 | } | ||
