| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: ecb.h,v 1.1 1999/09/03 08:41:12 mdw Exp $ |
| 4 | * |
| 5 | * Ciphertext block chaining for block ciphers |
| 6 | * |
| 7 | * (c) 1999 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of Catacomb. |
| 13 | * |
| 14 | * Catacomb is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU Library General Public License as |
| 16 | * published by the Free Software Foundation; either version 2 of the |
| 17 | * License, or (at your option) any later version. |
| 18 | * |
| 19 | * Catacomb is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU Library General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU Library General Public |
| 25 | * License along with Catacomb; if not, write to the Free |
| 26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 27 | * MA 02111-1307, USA. |
| 28 | */ |
| 29 | |
| 30 | /*----- Revision history --------------------------------------------------* |
| 31 | * |
| 32 | * $Log: ecb.h,v $ |
| 33 | * Revision 1.1 1999/09/03 08:41:12 mdw |
| 34 | * Initial import. |
| 35 | * |
| 36 | */ |
| 37 | |
| 38 | #ifndef ECB_H |
| 39 | #define ECB_H |
| 40 | |
| 41 | #ifdef __cplusplus |
| 42 | extern "C" { |
| 43 | #endif |
| 44 | |
| 45 | /*----- Header files ------------------------------------------------------*/ |
| 46 | |
| 47 | #include <assert.h> |
| 48 | #include <string.h> |
| 49 | |
| 50 | #include <mLib/bits.h> |
| 51 | |
| 52 | #ifndef BLKC_H |
| 53 | # include "blkc.h" |
| 54 | #endif |
| 55 | |
| 56 | /*----- Macros ------------------------------------------------------------*/ |
| 57 | |
| 58 | /* --- @ECB_DECL@ --- * |
| 59 | * |
| 60 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
| 61 | * |
| 62 | * Use: Creates declarations for ECB stealing mode. |
| 63 | */ |
| 64 | |
| 65 | #define ECB_DECL(PRE, pre) \ |
| 66 | \ |
| 67 | typedef struct pre ## _ecbctx { \ |
| 68 | pre ## _ctx ctx; /* Underlying cipher context */ \ |
| 69 | } pre ## _ecbctx; \ |
| 70 | \ |
| 71 | extern void pre ## _ecbsetkey(pre ## _ecbctx */*ctx*/, \ |
| 72 | const pre ## _ctx */*k*/); \ |
| 73 | \ |
| 74 | extern void pre ## _ecbinit(pre ## _ecbctx */*ctx*/, \ |
| 75 | const void */*key*/, size_t /*sz*/, \ |
| 76 | const void */*iv*/); \ |
| 77 | \ |
| 78 | extern void pre ## _ecbencrypt(pre ## _ecbctx */*ctx*/, \ |
| 79 | const void */*src*/, void */*dest*/, \ |
| 80 | size_t /*sz*/); \ |
| 81 | \ |
| 82 | extern void pre ## _ecbdecrypt(pre ## _ecbctx */*ctx*/, \ |
| 83 | const void */*src*/, void */*dest*/, \ |
| 84 | size_t /*sz*/); \ |
| 85 | |
| 86 | /* --- @ECB_DEF@ --- * |
| 87 | * |
| 88 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
| 89 | * |
| 90 | * Use: Creates an implementation for ECB stealing mode. |
| 91 | */ |
| 92 | |
| 93 | #define ECB_DEF(PRE, pre) \ |
| 94 | \ |
| 95 | /* --- @pre_ecbsetkey@ --- * \ |
| 96 | * \ |
| 97 | * Arguments: @pre_ecbctx *ctx@ = pointer to ECB context block \ |
| 98 | * @const pre_ctx *k@ = pointer to cipher context \ |
| 99 | * \ |
| 100 | * Returns: --- \ |
| 101 | * \ |
| 102 | * Use: Sets the ECB context to use a different cipher key. \ |
| 103 | */ \ |
| 104 | \ |
| 105 | void pre ## _ecbsetkey(pre ## _ecbctx *ctx, const pre ## _ctx *k) \ |
| 106 | { \ |
| 107 | ctx->ctx = *k; \ |
| 108 | } \ |
| 109 | \ |
| 110 | /* --- @pre_ecbinit@ --- * \ |
| 111 | * \ |
| 112 | * Arguments: @pre_ecbctx *ctx@ = pointer to cipher context \ |
| 113 | * @const void *key@ = pointer to the key buffer \ |
| 114 | * @size_t sz@ = size of the key \ |
| 115 | * @const void *iv@ = pointer to initialization vector \ |
| 116 | * \ |
| 117 | * Returns: --- \ |
| 118 | * \ |
| 119 | * Use: Initializes an ECB context ready for use. This is \ |
| 120 | * equivalent to calls to @pre_init@ and @pre_setkey@. \ |
| 121 | */ \ |
| 122 | \ |
| 123 | void pre ## _ecbinit(pre ## _ecbctx *ctx, \ |
| 124 | const void *key, size_t sz, \ |
| 125 | const void *iv) \ |
| 126 | { \ |
| 127 | pre ## _init(&ctx->ctx, key, sz); \ |
| 128 | } \ |
| 129 | \ |
| 130 | /* --- @pre_ecbencrypt@ --- * \ |
| 131 | * \ |
| 132 | * Arguments: @pre_ecbctx *ctx@ = pointer to ECB context block \ |
| 133 | * @const void *src@ = pointer to source data \ |
| 134 | * @void *dest@ = pointer to destination data \ |
| 135 | * @size_t sz@ = size of block to be encrypted \ |
| 136 | * \ |
| 137 | * Returns: --- \ |
| 138 | * \ |
| 139 | * Use: Encrypts a block with a block cipher in ECB mode, with \ |
| 140 | * ciphertext stealing and other clever tricks. \ |
| 141 | * Essentially, data can be encrypted in arbitrary sized \ |
| 142 | * chunks, although decryption must use the same chunks. \ |
| 143 | */ \ |
| 144 | \ |
| 145 | void pre ## _ecbencrypt(pre ## _ecbctx *ctx, \ |
| 146 | const void *src, void *dest, \ |
| 147 | size_t sz) \ |
| 148 | { \ |
| 149 | const octet *s = src; \ |
| 150 | octet *d = dest; \ |
| 151 | \ |
| 152 | /* --- Empty blocks are trivial --- */ \ |
| 153 | \ |
| 154 | if (!sz) \ |
| 155 | return; \ |
| 156 | \ |
| 157 | /* --- Short blocks aren't allowed in ECB --- * \ |
| 158 | * \ |
| 159 | * There's absolutely nothing secure I can do with them. \ |
| 160 | */ \ |
| 161 | \ |
| 162 | assert(((void)"ECB must have at least one whole block to work with", \ |
| 163 | sz >= PRE ## _BLKSZ)); \ |
| 164 | \ |
| 165 | /* --- Do the main chunk of encryption --- * \ |
| 166 | * \ |
| 167 | * This will do the whole lot if it's a whole number of blocks. Just \ |
| 168 | * give each block to the cipher in turn. This is trivial. \ |
| 169 | * Hopefully... \ |
| 170 | */ \ |
| 171 | \ |
| 172 | while (sz >= 2 * PRE ## _BLKSZ || sz == PRE ## _BLKSZ) { \ |
| 173 | uint32 x[PRE ## _BLKSZ / 4]; \ |
| 174 | BLKC_LOAD(PRE, x, s); \ |
| 175 | pre ## _eblk(&ctx->ctx, x, x); \ |
| 176 | BLKC_STORE(PRE, d, x); \ |
| 177 | s += PRE ## _BLKSZ; \ |
| 178 | d += PRE ## _BLKSZ; \ |
| 179 | sz -= PRE ## _BLKSZ; \ |
| 180 | } \ |
| 181 | \ |
| 182 | /* --- Do the tail-end block and bit-left-over --- * \ |
| 183 | * \ |
| 184 | * This isn't very efficient. That shouldn't matter much. \ |
| 185 | */ \ |
| 186 | \ |
| 187 | if (sz) { \ |
| 188 | uint32 x[PRE ## _BLKSZ / 4]; \ |
| 189 | octet b[PRE ## _BLKSZ]; \ |
| 190 | unsigned i; \ |
| 191 | \ |
| 192 | /* --- Let @sz@ be the size of the partial block --- */ \ |
| 193 | \ |
| 194 | sz -= PRE ## _BLKSZ; \ |
| 195 | \ |
| 196 | /* --- First stage --- * \ |
| 197 | * \ |
| 198 | * Read in the current block, and encrypt it. The first part of \ |
| 199 | * the result is the partial ciphertext block. Don't write that \ |
| 200 | * out yet, because I've not read the partial plaintext block. \ |
| 201 | */ \ |
| 202 | \ |
| 203 | BLKC_LOAD(PRE, x, s); \ |
| 204 | pre ## _eblk(&ctx->ctx, x, x); \ |
| 205 | BLKC_STORE(PRE, b, x); \ |
| 206 | \ |
| 207 | /* --- Second stage --- * \ |
| 208 | * \ |
| 209 | * Now move in the partial plaintext block, writing out the \ |
| 210 | * ciphertext as I go. Then encrypt, and write the complete \ |
| 211 | * ciphertext block. \ |
| 212 | */ \ |
| 213 | \ |
| 214 | s += PRE ## _BLKSZ; \ |
| 215 | d += PRE ## _BLKSZ; \ |
| 216 | for (i = 0; i < sz; i++) { \ |
| 217 | register octet y = b[i]; \ |
| 218 | b[i] = s[i]; \ |
| 219 | d[i] = y; \ |
| 220 | } \ |
| 221 | BLKC_LOAD(PRE, x, b); \ |
| 222 | pre ## _eblk(&ctx->ctx, x, x); \ |
| 223 | BLKC_STORE(PRE, d - PRE ## _BLKSZ, x); \ |
| 224 | } \ |
| 225 | \ |
| 226 | /* --- Done --- */ \ |
| 227 | \ |
| 228 | return; \ |
| 229 | } \ |
| 230 | \ |
| 231 | /* --- @pre_ecbdecrypt@ --- * \ |
| 232 | * \ |
| 233 | * Arguments: @pre_ecbctx *ctx@ = pointer to ECB context block \ |
| 234 | * @const void *src@ = pointer to source data \ |
| 235 | * @void *dest@ = pointer to destination data \ |
| 236 | * @size_t sz@ = size of block to be encrypted \ |
| 237 | * \ |
| 238 | * Returns: --- \ |
| 239 | * \ |
| 240 | * Use: Encrypts a block with a block cipher in ECB mode, with \ |
| 241 | * ciphertext stealing and other clever tricks. \ |
| 242 | * Essentially, data can be encrypted in arbitrary sized \ |
| 243 | * chunks, although decryption must use the same chunks. \ |
| 244 | */ \ |
| 245 | \ |
| 246 | void pre ## _ecbdecrypt(pre ## _ecbctx *ctx, \ |
| 247 | const void *src, void *dest, \ |
| 248 | size_t sz) \ |
| 249 | { \ |
| 250 | const octet *s = src; \ |
| 251 | octet *d = dest; \ |
| 252 | \ |
| 253 | /* --- Empty blocks are trivial --- */ \ |
| 254 | \ |
| 255 | if (!sz) \ |
| 256 | return; \ |
| 257 | \ |
| 258 | /* --- Short blocks aren't allowed in ECB --- * \ |
| 259 | * \ |
| 260 | * There's absolutely nothing secure I can do with them. \ |
| 261 | */ \ |
| 262 | \ |
| 263 | assert(((void)"ECB must have at least one whole block to work with", \ |
| 264 | sz >= PRE ## _BLKSZ)); \ |
| 265 | \ |
| 266 | /* --- Do the main chunk of decryption --- * \ |
| 267 | * \ |
| 268 | * This will do the whole lot if it's a whole number of blocks. \ |
| 269 | * Each block is just handed to the block cipher in turn. \ |
| 270 | */ \ |
| 271 | \ |
| 272 | while (sz >= 2 * PRE ## _BLKSZ || sz == PRE ## _BLKSZ) { \ |
| 273 | uint32 x[PRE ## _BLKSZ / 4]; \ |
| 274 | BLKC_LOAD(PRE, x, s); \ |
| 275 | pre ## _dblk(&ctx->ctx, x, x); \ |
| 276 | BLKC_STORE(PRE, d, x); \ |
| 277 | s += PRE ## _BLKSZ; \ |
| 278 | d += PRE ## _BLKSZ; \ |
| 279 | sz -= PRE ## _BLKSZ; \ |
| 280 | } \ |
| 281 | \ |
| 282 | /* --- Do the tail-end block and bit-left-over --- * \ |
| 283 | * \ |
| 284 | * This isn't very efficient. That shouldn't matter much. \ |
| 285 | */ \ |
| 286 | \ |
| 287 | if (sz) { \ |
| 288 | uint32 x[PRE ## _BLKSZ / 4]; \ |
| 289 | octet b[PRE ## _BLKSZ]; \ |
| 290 | unsigned i; \ |
| 291 | \ |
| 292 | /* --- Let @sz@ be the size of the partial block --- */ \ |
| 293 | \ |
| 294 | sz -= PRE ## _BLKSZ; \ |
| 295 | \ |
| 296 | /* --- First stage --- * \ |
| 297 | * \ |
| 298 | * Take the complete ciphertext block, and decrypt it. This block \ |
| 299 | * is carried over for the next encryption operation. \ |
| 300 | */ \ |
| 301 | \ |
| 302 | BLKC_LOAD(PRE, x, s); \ |
| 303 | pre ## _dblk(&ctx->ctx, x, x); \ |
| 304 | BLKC_STORE(PRE, b, x); \ |
| 305 | \ |
| 306 | /* --- Second stage --- * \ |
| 307 | * \ |
| 308 | * The first few bytes are the partial plaintext block. Write that \ |
| 309 | * and replace with the partial ciphertext block. Then decrypt \ |
| 310 | * what's left as the complete plaintext. \ |
| 311 | */ \ |
| 312 | \ |
| 313 | s += PRE ## _BLKSZ; \ |
| 314 | d += PRE ## _BLKSZ; \ |
| 315 | for (i = 0; i < sz; i++) { \ |
| 316 | register octet y = s[i]; \ |
| 317 | d[i] = b[i]; \ |
| 318 | b[i] = y; \ |
| 319 | } \ |
| 320 | BLKC_LOAD(PRE, x, b); \ |
| 321 | pre ## _dblk(&ctx->ctx, x, x); \ |
| 322 | BLKC_STORE(PRE, d - PRE ## _BLKSZ, x); \ |
| 323 | } \ |
| 324 | \ |
| 325 | /* --- Done --- */ \ |
| 326 | \ |
| 327 | return; \ |
| 328 | } \ |
| 329 | \ |
| 330 | ECB_TEST(PRE, pre) |
| 331 | |
| 332 | /*----- Test rig ----------------------------------------------------------*/ |
| 333 | |
| 334 | #ifdef TEST_RIG |
| 335 | |
| 336 | #include <stdio.h> |
| 337 | |
| 338 | #include "daftstory.h" |
| 339 | |
| 340 | /* --- @ECB_TEST@ --- * |
| 341 | * |
| 342 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
| 343 | * |
| 344 | * Use: Standard test rig for ECB functions. |
| 345 | */ |
| 346 | |
| 347 | #define ECB_TEST(PRE, pre) \ |
| 348 | \ |
| 349 | /* --- Initial plaintext for the test --- */ \ |
| 350 | \ |
| 351 | static const octet text[] = TEXT; \ |
| 352 | \ |
| 353 | /* --- Key and IV to use --- */ \ |
| 354 | \ |
| 355 | static const octet key[] = KEY; \ |
| 356 | static const octet iv[] = IV; \ |
| 357 | \ |
| 358 | /* --- Buffers for encryption and decryption output --- */ \ |
| 359 | \ |
| 360 | static octet ct[sizeof(text)]; \ |
| 361 | static octet pt[sizeof(text)]; \ |
| 362 | \ |
| 363 | static void hexdump(const octet *p, size_t sz) \ |
| 364 | { \ |
| 365 | const octet *q = p + sz; \ |
| 366 | for (sz = 0; p < q; p++, sz++) { \ |
| 367 | printf("%02x", *p); \ |
| 368 | if ((sz + 1) % PRE ## _BLKSZ == 0) \ |
| 369 | putchar(':'); \ |
| 370 | } \ |
| 371 | } \ |
| 372 | \ |
| 373 | int main(void) \ |
| 374 | { \ |
| 375 | size_t sz = 0, rest; \ |
| 376 | pre ## _ecbctx ctx; \ |
| 377 | int status = 0; \ |
| 378 | int done = 0; \ |
| 379 | \ |
| 380 | size_t keysz = PRE ## _KEYSZ ? \ |
| 381 | PRE ## _KEYSZ : strlen((const char *)key); \ |
| 382 | \ |
| 383 | fputs(#pre "-ecb: ", stdout); \ |
| 384 | \ |
| 385 | pre ## _ecbinit(&ctx, key, keysz, iv); \ |
| 386 | \ |
| 387 | while (sz <= sizeof(text)) { \ |
| 388 | rest = sizeof(text) - sz; \ |
| 389 | if ((sz != 0 && sz < PRE ## _BLKSZ) || \ |
| 390 | (rest != 0 && rest < PRE ## _BLKSZ)) \ |
| 391 | goto next; \ |
| 392 | memcpy(ct, text, sizeof(text)); \ |
| 393 | pre ## _ecbencrypt(&ctx, ct, ct, sz); \ |
| 394 | pre ## _ecbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
| 395 | memcpy(pt, ct, sizeof(text)); \ |
| 396 | pre ## _ecbdecrypt(&ctx, pt, pt, sz); \ |
| 397 | pre ## _ecbdecrypt(&ctx, pt + sz, pt + sz, rest); \ |
| 398 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
| 399 | done++; \ |
| 400 | if (sizeof(text) < 40 || done % 8 == 0) \ |
| 401 | fputc('.', stdout); \ |
| 402 | if (done % 480 == 0) \ |
| 403 | fputs("\n\t", stdout); \ |
| 404 | fflush(stdout); \ |
| 405 | } else { \ |
| 406 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
| 407 | status = 1; \ |
| 408 | printf("\tplaintext = "); hexdump(text, sz); \ |
| 409 | printf(", "); hexdump(text + sz, rest); \ |
| 410 | fputc('\n', stdout); \ |
| 411 | printf("\tciphertext = "); hexdump(ct, sz); \ |
| 412 | printf(", "); hexdump(ct + sz, rest); \ |
| 413 | fputc('\n', stdout); \ |
| 414 | printf("\trecovered text = "); hexdump(pt, sz); \ |
| 415 | printf(", "); hexdump(pt + sz, rest); \ |
| 416 | fputc('\n', stdout); \ |
| 417 | fputc('\n', stdout); \ |
| 418 | } \ |
| 419 | next: \ |
| 420 | if (sz < 63) \ |
| 421 | sz++; \ |
| 422 | else \ |
| 423 | sz += 9; \ |
| 424 | } \ |
| 425 | \ |
| 426 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
| 427 | return (status); \ |
| 428 | } |
| 429 | |
| 430 | #else |
| 431 | # define ECB_TEST(PRE, pre) |
| 432 | #endif |
| 433 | |
| 434 | /*----- That's all, folks -------------------------------------------------*/ |
| 435 | |
| 436 | #ifdef __cplusplus |
| 437 | } |
| 438 | #endif |
| 439 | |
| 440 | #endif |