San Mehat | a430b2b | 2014-09-23 08:30:51 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) The Internet Society (2001). All Rights Reserved. |
| 3 | * |
| 4 | * This document and translations of it may be copied and furnished to |
| 5 | * others, and derivative works that comment on or otherwise explain it |
| 6 | * or assist in its implementation may be prepared, copied, published |
| 7 | * and distributed, in whole or in part, without restriction of any |
| 8 | * kind, provided that the above copyright notice and this paragraph are |
| 9 | * included on all such copies and derivative works. However, this |
| 10 | * document itself may not be modified in any way, such as by removing |
| 11 | * the copyright notice or references to the Internet Society or other |
| 12 | * Internet organizations, except as needed for the purpose of |
| 13 | * developing Internet standards in which case the procedures for |
| 14 | * copyrights defined in the Internet Standards process must be |
| 15 | * followed, or as required to translate it into languages other than |
| 16 | * English. |
| 17 | * |
| 18 | * The limited permissions granted above are perpetual and will not be |
| 19 | * revoked by the Internet Society or its successors or assigns. |
| 20 | * |
| 21 | * This document and the information contained herein is provided on an |
| 22 | * "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING |
| 23 | * TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING |
| 24 | * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION |
| 25 | * HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF |
| 26 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. |
| 27 | */ |
| 28 | |
| 29 | /* |
| 30 | * sha1.c |
| 31 | * |
| 32 | * Description: |
| 33 | * This file implements the Secure Hashing Algorithm 1 as |
| 34 | * defined in FIPS PUB 180-1 published April 17, 1995. |
| 35 | * |
| 36 | * The SHA-1, produces a 160-bit message digest for a given |
| 37 | * data stream. It should take about 2**n steps to find a |
| 38 | * message with the same digest as a given message and |
| 39 | * 2**(n/2) to find any two messages with the same digest, |
| 40 | * when n is the digest size in bits. Therefore, this |
| 41 | * algorithm can serve as a means of providing a |
| 42 | * "fingerprint" for a message. |
| 43 | * |
| 44 | * Portability Issues: |
| 45 | * SHA-1 is defined in terms of 32-bit "words". This code |
| 46 | * uses <stdint.h> (included via "sha1.h" to define 32 and 8 |
| 47 | * bit unsigned integer types. If your C compiler does not |
| 48 | * support 32 bit unsigned integers, this code is not |
| 49 | * appropriate. |
| 50 | * |
| 51 | * Caveats: |
| 52 | * SHA-1 is designed to work with messages less than 2^64 bits |
| 53 | * long. Although SHA-1 allows a message digest to be generated |
| 54 | * for messages of any number of bits less than 2^64, this |
| 55 | * implementation only works with messages with a length that is |
| 56 | * a multiple of the size of an 8-bit character. |
| 57 | * |
| 58 | */ |
| 59 | |
| 60 | #include "sha1.h" |
| 61 | |
| 62 | /* |
| 63 | * Define the SHA1 circular left shift macro |
| 64 | */ |
| 65 | #define SHA1CircularShift(bits,word) \ |
| 66 | (((word) << (bits)) | ((word) >> (32-(bits)))) |
| 67 | |
| 68 | /* Local Function Prototyptes */ |
| 69 | void SHA1PadMessage(SHA1Context *); |
| 70 | void SHA1ProcessMessageBlock(SHA1Context *); |
| 71 | |
| 72 | /* |
| 73 | * SHA1Reset |
| 74 | * |
| 75 | * Description: |
| 76 | * This function will initialize the SHA1Context in preparation |
| 77 | * for computing a new SHA1 message digest. |
| 78 | * |
| 79 | * Parameters: |
| 80 | * context: [in/out] |
| 81 | * The context to reset. |
| 82 | * |
| 83 | * Returns: |
| 84 | * sha Error Code. |
| 85 | * |
| 86 | */ |
| 87 | int SHA1Reset(SHA1Context *context) |
| 88 | { |
| 89 | if (!context) |
| 90 | { |
| 91 | return shaNull; |
| 92 | } |
| 93 | |
| 94 | context->Length_Low = 0; |
| 95 | context->Length_High = 0; |
| 96 | context->Message_Block_Index = 0; |
| 97 | |
| 98 | context->Intermediate_Hash[0] = 0x67452301; |
| 99 | context->Intermediate_Hash[1] = 0xEFCDAB89; |
| 100 | context->Intermediate_Hash[2] = 0x98BADCFE; |
| 101 | context->Intermediate_Hash[3] = 0x10325476; |
| 102 | context->Intermediate_Hash[4] = 0xC3D2E1F0; |
| 103 | |
| 104 | context->Computed = 0; |
| 105 | context->Corrupted = 0; |
| 106 | return shaSuccess; |
| 107 | } |
| 108 | |
| 109 | /* |
| 110 | * SHA1Result |
| 111 | * |
| 112 | * Description: |
| 113 | * This function will return the 160-bit message digest into the |
| 114 | * Message_Digest array provided by the caller. |
| 115 | * NOTE: The first octet of hash is stored in the 0th element, |
| 116 | * the last octet of hash in the 19th element. |
| 117 | * |
| 118 | * Parameters: |
| 119 | * context: [in/out] |
| 120 | * The context to use to calculate the SHA-1 hash. |
| 121 | * Message_Digest: [out] |
| 122 | * Where the digest is returned. |
| 123 | * |
| 124 | * Returns: |
| 125 | * sha Error Code. |
| 126 | * |
| 127 | */ |
| 128 | int SHA1Result( SHA1Context *context, |
| 129 | uint8_t Message_Digest[SHA1HashSize]) |
| 130 | { |
| 131 | int i; |
| 132 | |
| 133 | if (!context || !Message_Digest) |
| 134 | { |
| 135 | return shaNull; |
| 136 | } |
| 137 | |
| 138 | if (context->Corrupted) |
| 139 | { |
| 140 | return context->Corrupted; |
| 141 | } |
| 142 | |
| 143 | if (!context->Computed) |
| 144 | { |
| 145 | SHA1PadMessage(context); |
| 146 | for(i=0; i<64; ++i) |
| 147 | { |
| 148 | /* message may be sensitive, clear it out */ |
| 149 | context->Message_Block[i] = 0; |
| 150 | } |
| 151 | context->Length_Low = 0; /* and clear length */ |
| 152 | context->Length_High = 0; |
| 153 | context->Computed = 1; |
| 154 | } |
| 155 | |
| 156 | for(i = 0; i < SHA1HashSize; ++i) |
| 157 | { |
| 158 | Message_Digest[i] = context->Intermediate_Hash[i>>2] |
| 159 | >> 8 * ( 3 - ( i & 0x03 ) ); |
| 160 | } |
| 161 | |
| 162 | return shaSuccess; |
| 163 | } |
| 164 | |
| 165 | /* |
| 166 | * SHA1Input |
| 167 | * |
| 168 | * Description: |
| 169 | * This function accepts an array of octets as the next portion |
| 170 | * of the message. |
| 171 | * |
| 172 | * Parameters: |
| 173 | * context: [in/out] |
| 174 | * The SHA context to update |
| 175 | * message_array: [in] |
| 176 | * An array of characters representing the next portion of |
| 177 | * the message. |
| 178 | * length: [in] |
| 179 | * The length of the message in message_array |
| 180 | * |
| 181 | * Returns: |
| 182 | * sha Error Code. |
| 183 | * |
| 184 | */ |
| 185 | int SHA1Input( SHA1Context *context, |
| 186 | const uint8_t *message_array, |
| 187 | unsigned length) |
| 188 | { |
| 189 | if (!length) |
| 190 | { |
| 191 | return shaSuccess; |
| 192 | } |
| 193 | |
| 194 | if (!context || !message_array) |
| 195 | { |
| 196 | return shaNull; |
| 197 | } |
| 198 | |
| 199 | if (context->Computed) |
| 200 | { |
| 201 | context->Corrupted = shaStateError; |
| 202 | return shaStateError; |
| 203 | } |
| 204 | |
| 205 | if (context->Corrupted) |
| 206 | { |
| 207 | return context->Corrupted; |
| 208 | } |
| 209 | while(length-- && !context->Corrupted) |
| 210 | { |
| 211 | context->Message_Block[context->Message_Block_Index++] = |
| 212 | (*message_array & 0xFF); |
| 213 | |
| 214 | context->Length_Low += 8; |
| 215 | if (context->Length_Low == 0) |
| 216 | { |
| 217 | context->Length_High++; |
| 218 | if (context->Length_High == 0) |
| 219 | { |
| 220 | /* Message is too long */ |
| 221 | context->Corrupted = 1; |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | if (context->Message_Block_Index == 64) |
| 226 | { |
| 227 | SHA1ProcessMessageBlock(context); |
| 228 | } |
| 229 | |
| 230 | message_array++; |
| 231 | } |
| 232 | |
| 233 | return shaSuccess; |
| 234 | } |
| 235 | |
| 236 | /* |
| 237 | * SHA1ProcessMessageBlock |
| 238 | * |
| 239 | * Description: |
| 240 | * This function will process the next 512 bits of the message |
| 241 | * stored in the Message_Block array. |
| 242 | * |
| 243 | * Parameters: |
| 244 | * None. |
| 245 | * |
| 246 | * Returns: |
| 247 | * Nothing. |
| 248 | * |
| 249 | * Comments: |
| 250 | * Many of the variable names in this code, especially the |
| 251 | * single character names, were used because those were the |
| 252 | * names used in the publication. |
| 253 | * |
| 254 | * |
| 255 | */ |
| 256 | void SHA1ProcessMessageBlock(SHA1Context *context) |
| 257 | { |
| 258 | const uint32_t K[] = { /* Constants defined in SHA-1 */ |
| 259 | 0x5A827999, |
| 260 | 0x6ED9EBA1, |
| 261 | 0x8F1BBCDC, |
| 262 | 0xCA62C1D6 |
| 263 | }; |
| 264 | int t; /* Loop counter */ |
| 265 | uint32_t temp; /* Temporary word value */ |
| 266 | uint32_t W[80]; /* Word sequence */ |
| 267 | uint32_t A, B, C, D, E; /* Word buffers */ |
| 268 | |
| 269 | /* |
| 270 | * Initialize the first 16 words in the array W |
| 271 | */ |
| 272 | for(t = 0; t < 16; t++) |
| 273 | { |
| 274 | W[t] = context->Message_Block[t * 4] << 24; |
| 275 | W[t] |= context->Message_Block[t * 4 + 1] << 16; |
| 276 | W[t] |= context->Message_Block[t * 4 + 2] << 8; |
| 277 | W[t] |= context->Message_Block[t * 4 + 3]; |
| 278 | } |
| 279 | |
| 280 | for(t = 16; t < 80; t++) |
| 281 | { |
| 282 | W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]); |
| 283 | } |
| 284 | |
| 285 | A = context->Intermediate_Hash[0]; |
| 286 | B = context->Intermediate_Hash[1]; |
| 287 | C = context->Intermediate_Hash[2]; |
| 288 | D = context->Intermediate_Hash[3]; |
| 289 | E = context->Intermediate_Hash[4]; |
| 290 | |
| 291 | for(t = 0; t < 20; t++) |
| 292 | { |
| 293 | temp = SHA1CircularShift(5,A) + |
| 294 | ((B & C) | ((~B) & D)) + E + W[t] + K[0]; |
| 295 | E = D; |
| 296 | D = C; |
| 297 | C = SHA1CircularShift(30,B); |
| 298 | B = A; |
| 299 | A = temp; |
| 300 | } |
| 301 | |
| 302 | for(t = 20; t < 40; t++) |
| 303 | { |
| 304 | temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1]; |
| 305 | E = D; |
| 306 | D = C; |
| 307 | C = SHA1CircularShift(30,B); |
| 308 | B = A; |
| 309 | A = temp; |
| 310 | } |
| 311 | |
| 312 | for(t = 40; t < 60; t++) |
| 313 | { |
| 314 | temp = SHA1CircularShift(5,A) + |
| 315 | ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2]; |
| 316 | E = D; |
| 317 | D = C; |
| 318 | C = SHA1CircularShift(30,B); |
| 319 | B = A; |
| 320 | A = temp; |
| 321 | } |
| 322 | |
| 323 | for(t = 60; t < 80; t++) |
| 324 | { |
| 325 | temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3]; |
| 326 | E = D; |
| 327 | D = C; |
| 328 | C = SHA1CircularShift(30,B); |
| 329 | B = A; |
| 330 | A = temp; |
| 331 | } |
| 332 | |
| 333 | context->Intermediate_Hash[0] += A; |
| 334 | context->Intermediate_Hash[1] += B; |
| 335 | context->Intermediate_Hash[2] += C; |
| 336 | context->Intermediate_Hash[3] += D; |
| 337 | context->Intermediate_Hash[4] += E; |
| 338 | |
| 339 | context->Message_Block_Index = 0; |
| 340 | } |
| 341 | |
| 342 | |
| 343 | /* |
| 344 | * SHA1PadMessage |
| 345 | * |
| 346 | * Description: |
| 347 | * According to the standard, the message must be padded to an even |
| 348 | * 512 bits. The first padding bit must be a '1'. The last 64 |
| 349 | * bits represent the length of the original message. All bits in |
| 350 | * between should be 0. This function will pad the message |
| 351 | * according to those rules by filling the Message_Block array |
| 352 | * accordingly. It will also call the ProcessMessageBlock function |
| 353 | * provided appropriately. When it returns, it can be assumed that |
| 354 | * the message digest has been computed. |
| 355 | * |
| 356 | * Parameters: |
| 357 | * context: [in/out] |
| 358 | * The context to pad |
| 359 | * ProcessMessageBlock: [in] |
| 360 | * The appropriate SHA*ProcessMessageBlock function |
| 361 | * Returns: |
| 362 | * Nothing. |
| 363 | * |
| 364 | */ |
| 365 | |
| 366 | void SHA1PadMessage(SHA1Context *context) |
| 367 | { |
| 368 | /* |
| 369 | * Check to see if the current message block is too small to hold |
| 370 | * the initial padding bits and length. If so, we will pad the |
| 371 | * block, process it, and then continue padding into a second |
| 372 | * block. |
| 373 | */ |
| 374 | if (context->Message_Block_Index > 55) |
| 375 | { |
| 376 | context->Message_Block[context->Message_Block_Index++] = 0x80; |
| 377 | while(context->Message_Block_Index < 64) |
| 378 | { |
| 379 | context->Message_Block[context->Message_Block_Index++] = 0; |
| 380 | } |
| 381 | |
| 382 | SHA1ProcessMessageBlock(context); |
| 383 | |
| 384 | while(context->Message_Block_Index < 56) |
| 385 | { |
| 386 | context->Message_Block[context->Message_Block_Index++] = 0; |
| 387 | } |
| 388 | } |
| 389 | else |
| 390 | { |
| 391 | context->Message_Block[context->Message_Block_Index++] = 0x80; |
| 392 | while(context->Message_Block_Index < 56) |
| 393 | { |
| 394 | context->Message_Block[context->Message_Block_Index++] = 0; |
| 395 | } |
| 396 | } |
| 397 | |
| 398 | /* |
| 399 | * Store the message length as the last 8 octets |
| 400 | */ |
| 401 | context->Message_Block[56] = context->Length_High >> 24; |
| 402 | context->Message_Block[57] = context->Length_High >> 16; |
| 403 | context->Message_Block[58] = context->Length_High >> 8; |
| 404 | context->Message_Block[59] = context->Length_High; |
| 405 | context->Message_Block[60] = context->Length_Low >> 24; |
| 406 | context->Message_Block[61] = context->Length_Low >> 16; |
| 407 | context->Message_Block[62] = context->Length_Low >> 8; |
| 408 | context->Message_Block[63] = context->Length_Low; |
| 409 | |
| 410 | SHA1ProcessMessageBlock(context); |
| 411 | } |