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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: cfb-def.h,v 1.4 2004/04/02 01:03:49 mdw Exp $ |
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4 | * |
5 | * Definitions for ciphertext feedback mode |
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: cfb-def.h,v $ |
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33 | * Revision 1.4 2004/04/02 01:03:49 mdw |
34 | * Miscellaneous constification. |
35 | * |
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36 | * Revision 1.3 2001/06/17 00:10:51 mdw |
37 | * Typesetting fixes |
38 | * |
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39 | * Revision 1.2 2000/06/17 10:50:39 mdw |
40 | * Use secure arena for memory allocation. Rearrange setiv slightly. |
41 | * |
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42 | * Revision 1.1 1999/12/10 23:16:39 mdw |
43 | * Split mode macros into interface and implementation. |
44 | * |
45 | */ |
46 | |
47 | #ifndef CATACOMB_CFB_DEF_H |
48 | #define CATACOMB_CFB_DEF_H |
49 | |
50 | #ifdef __cplusplus |
51 | extern "C" { |
52 | #endif |
53 | |
54 | /*----- Header files ------------------------------------------------------*/ |
55 | |
56 | #include <string.h> |
57 | |
58 | #include <mLib/bits.h> |
59 | #include <mLib/sub.h> |
60 | |
426aab6b |
61 | #ifndef CATACOMB_ARENA_H |
62 | # include "arena.h" |
63 | #endif |
64 | |
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65 | #ifndef CATACOMB_BLKC_H |
66 | # include "blkc.h" |
67 | #endif |
68 | |
69 | #ifndef CATACOMB_GCIPHER_H |
70 | # include "gcipher.h" |
71 | #endif |
72 | |
73 | #ifndef CATACOMB_PARANOIA_H |
74 | # include "paranoia.h" |
75 | #endif |
76 | |
426aab6b |
77 | #ifndef CATACOMB_PARANOIA_H |
78 | # include "paranoia.h" |
79 | #endif |
80 | |
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81 | /*----- Macros ------------------------------------------------------------*/ |
82 | |
83 | /* --- @CFB_DEF@ --- * |
84 | * |
85 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
86 | * |
87 | * Use: Creates an implementation for CFB mode. |
88 | */ |
89 | |
90 | #define CFB_DEF(PRE, pre) \ |
91 | \ |
92 | /* --- @pre_cfbgetiv@ --- * \ |
93 | * \ |
94 | * Arguments: @const pre_cfbctx *ctx@ = pointer to CFB context block \ |
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95 | * @void *iv@ = pointer to output data block \ |
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96 | * \ |
97 | * Returns: --- \ |
98 | * \ |
99 | * Use: Reads the currently set IV. Reading and setting an IV \ |
100 | * is not transparent to the cipher. It will add a `step' \ |
101 | * which must be matched by a similar operation during \ |
102 | * decryption. \ |
103 | */ \ |
104 | \ |
105 | void pre##_cfbgetiv(const pre##_cfbctx *ctx, void *iv) \ |
106 | { \ |
107 | octet *p = iv; \ |
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108 | unsigned off = ctx->off; \ |
109 | unsigned rest = PRE##_BLKSZ - off; \ |
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110 | memcpy(p, ctx->iv + off, rest); \ |
111 | memcpy(p + rest, ctx->iv, off); \ |
112 | } \ |
113 | \ |
114 | /* --- @pre_cfbsetiv@ --- * \ |
115 | * \ |
116 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
117 | * @cnost void *iv@ = pointer to IV to set \ |
118 | * \ |
119 | * Returns: --- \ |
120 | * \ |
121 | * Use: Sets the IV to use for subsequent encryption. \ |
122 | */ \ |
123 | \ |
124 | void pre##_cfbsetiv(pre##_cfbctx *ctx, const void *iv) \ |
125 | { \ |
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126 | memcpy(ctx->iv, iv, PRE##_BLKSZ); \ |
127 | ctx->off = PRE##_BLKSZ; \ |
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128 | } \ |
129 | \ |
130 | /* --- @pre_cfbbdry@ --- * \ |
131 | * \ |
132 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
133 | * \ |
134 | * Returns: --- \ |
135 | * \ |
136 | * Use: Inserts a boundary during encryption. Successful \ |
137 | * decryption must place a similar boundary. \ |
138 | */ \ |
139 | \ |
140 | void pre##_cfbbdry(pre##_cfbctx *ctx) \ |
141 | { \ |
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142 | uint32 niv[PRE##_BLKSZ / 4]; \ |
143 | BLKC_LOAD(PRE, niv, ctx->iv); \ |
144 | pre##_eblk(&ctx->ctx, niv, niv); \ |
145 | BLKC_STORE(PRE, ctx->iv, niv); \ |
146 | ctx->off = PRE##_BLKSZ; \ |
147 | BURN(niv); \ |
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148 | } \ |
149 | \ |
150 | /* --- @pre_cfbsetkey@ --- * \ |
151 | * \ |
152 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
153 | * @const pre_ctx *k@ = pointer to cipher context \ |
154 | * \ |
155 | * Returns: --- \ |
156 | * \ |
157 | * Use: Sets the CFB context to use a different cipher key. \ |
158 | */ \ |
159 | \ |
160 | void pre##_cfbsetkey(pre##_cfbctx *ctx, const pre##_ctx *k) \ |
161 | { \ |
162 | ctx->ctx = *k; \ |
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163 | ctx->off = PRE##_BLKSZ; \ |
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164 | } \ |
165 | \ |
166 | /* --- @pre_cfbinit@ --- * \ |
167 | * \ |
168 | * Arguments: @pre_cfbctx *ctx@ = pointer to cipher context \ |
169 | * @const void *key@ = pointer to the key buffer \ |
170 | * @size_t sz@ = size of the key \ |
171 | * @const void *iv@ = pointer to initialization vector \ |
172 | * \ |
173 | * Returns: --- \ |
174 | * \ |
175 | * Use: Initializes a CFB context ready for use. You should \ |
176 | * ensure that the IV chosen is unique: reusing an IV will \ |
177 | * compromise the security of at least the first block \ |
178 | * encrypted. This is equivalent to calls to @pre_init@, \ |
179 | * @pre_cfbsetkey@ and @pre_cfbsetiv@. \ |
180 | */ \ |
181 | \ |
182 | void pre##_cfbinit(pre##_cfbctx *ctx, \ |
183 | const void *key, size_t sz, \ |
184 | const void *iv) \ |
185 | { \ |
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186 | static const octet zero[PRE##_BLKSZ] = { 0 }; \ |
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187 | pre##_init(&ctx->ctx, key, sz); \ |
188 | pre##_cfbsetiv(ctx, iv ? iv : zero); \ |
189 | } \ |
190 | \ |
191 | /* --- @pre_cfbencrypt@ --- * \ |
192 | * \ |
193 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
194 | * @const void *src@ = pointer to source data \ |
195 | * @void *dest@ = pointer to destination data \ |
196 | * @size_t sz@ = size of block to be encrypted \ |
197 | * \ |
198 | * Returns: --- \ |
199 | * \ |
200 | * Use: Encrypts a block with a block cipher in CFB mode. The \ |
201 | * input block may be arbitrary in size. CFB mode is not \ |
202 | * sensitive to block boundaries. \ |
203 | */ \ |
204 | \ |
205 | void pre##_cfbencrypt(pre##_cfbctx *ctx, \ |
206 | const void *src, void *dest, \ |
207 | size_t sz) \ |
208 | { \ |
209 | const octet *s = src; \ |
210 | octet *d = dest; \ |
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211 | unsigned off = ctx->off; \ |
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212 | \ |
213 | /* --- Empty blocks are trivial --- */ \ |
214 | \ |
215 | if (!sz) \ |
216 | return; \ |
217 | \ |
218 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
219 | \ |
220 | if (sz < PRE##_BLKSZ - off) \ |
221 | goto small; \ |
222 | \ |
223 | /* --- Finish off what's left in my buffer --- */ \ |
224 | \ |
225 | while (off < PRE##_BLKSZ) { \ |
226 | register octet x = *s++; \ |
227 | *d++ = ctx->iv[off++] ^= x; \ |
228 | sz--; \ |
229 | } \ |
230 | \ |
231 | /* --- Main encryption loop --- */ \ |
232 | \ |
233 | { \ |
234 | uint32 iv[PRE##_BLKSZ / 4]; \ |
235 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
236 | \ |
237 | for (;;) { \ |
238 | pre##_eblk(&ctx->ctx, iv, iv); \ |
239 | if (sz < PRE##_BLKSZ) \ |
240 | break; \ |
241 | BLKC_XLOAD(PRE, iv, s); \ |
242 | BLKC_STORE(PRE, d, iv); \ |
243 | s += PRE##_BLKSZ; \ |
244 | d += PRE##_BLKSZ; \ |
245 | sz -= PRE##_BLKSZ; \ |
246 | } \ |
247 | off = 0; \ |
248 | BLKC_STORE(PRE, ctx->iv, iv); \ |
249 | } \ |
250 | \ |
251 | /* --- Tidying up the tail end --- */ \ |
252 | \ |
253 | if (sz) { \ |
254 | small: \ |
255 | do { \ |
256 | register octet x = *s++; \ |
257 | *d++ = ctx->iv[off++] ^= x; \ |
258 | sz--; \ |
259 | } while (sz); \ |
260 | } \ |
261 | \ |
262 | /* --- Done --- */ \ |
263 | \ |
264 | ctx->off = off; \ |
265 | return; \ |
266 | } \ |
267 | \ |
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268 | /* --- @pre_cfbdecrypt@ --- * \ |
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269 | * \ |
270 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
271 | * @const void *src@ = pointer to source data \ |
272 | * @void *dest@ = pointer to destination data \ |
273 | * @size_t sz@ = size of block to be encrypted \ |
274 | * \ |
275 | * Returns: --- \ |
276 | * \ |
277 | * Use: Decrypts a block with a block cipher in CFB mode. The \ |
278 | * input block may be arbitrary in size. CFB mode is not \ |
279 | * sensitive to block boundaries. \ |
280 | */ \ |
281 | \ |
282 | void pre##_cfbdecrypt(pre##_cfbctx *ctx, \ |
283 | const void *src, void *dest, \ |
284 | size_t sz) \ |
285 | { \ |
286 | const octet *s = src; \ |
287 | octet *d = dest; \ |
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288 | unsigned off = ctx->off; \ |
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289 | \ |
290 | /* --- Empty blocks are trivial --- */ \ |
291 | \ |
292 | if (!sz) \ |
293 | return; \ |
294 | \ |
295 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
296 | \ |
297 | if (sz < PRE##_BLKSZ - off) \ |
298 | goto small; \ |
299 | \ |
300 | /* --- Finish off what's left in my buffer --- */ \ |
301 | \ |
302 | while (off < PRE##_BLKSZ) { \ |
303 | register octet x = *s++; \ |
304 | *d++ = ctx->iv[off] ^ x; \ |
305 | ctx->iv[off++] = x; \ |
306 | sz--; \ |
307 | } \ |
308 | \ |
309 | /* --- Main encryption loop --- */ \ |
310 | \ |
311 | { \ |
312 | uint32 iv[PRE##_BLKSZ / 4]; \ |
313 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
314 | \ |
315 | for (;;) { \ |
316 | uint32 x[PRE##_BLKSZ / 4]; \ |
317 | pre##_eblk(&ctx->ctx, iv, iv); \ |
318 | if (sz < PRE##_BLKSZ) \ |
319 | break; \ |
320 | BLKC_LOAD(PRE, x, s); \ |
321 | BLKC_XSTORE(PRE, d, iv, x); \ |
322 | BLKC_MOVE(PRE, iv, x); \ |
323 | s += PRE##_BLKSZ; \ |
324 | d += PRE##_BLKSZ; \ |
325 | sz -= PRE##_BLKSZ; \ |
326 | } \ |
327 | off = 0; \ |
328 | BLKC_STORE(PRE, ctx->iv, iv); \ |
329 | } \ |
330 | \ |
331 | /* --- Tidying up the tail end --- */ \ |
332 | \ |
333 | if (sz) { \ |
334 | small: \ |
335 | do { \ |
336 | register octet x = *s++; \ |
337 | *d++ = ctx->iv[off] ^ x; \ |
338 | ctx->iv[off++] = x; \ |
339 | sz--; \ |
340 | } while (sz); \ |
341 | } \ |
342 | \ |
343 | /* --- Done --- */ \ |
344 | \ |
345 | ctx->off = off; \ |
346 | return; \ |
347 | } \ |
348 | \ |
349 | /* --- Generic cipher interface --- */ \ |
350 | \ |
351 | static const gcipher_ops gops; \ |
352 | \ |
353 | typedef struct gctx { \ |
354 | gcipher c; \ |
355 | pre##_cfbctx k; \ |
356 | } gctx; \ |
357 | \ |
358 | static gcipher *ginit(const void *k, size_t sz) \ |
359 | { \ |
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360 | gctx *g = S_CREATE(gctx); \ |
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361 | g->c.ops = &gops; \ |
362 | pre##_cfbinit(&g->k, k, sz, 0); \ |
363 | return (&g->c); \ |
364 | } \ |
365 | \ |
366 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
367 | { \ |
368 | gctx *g = (gctx *)c; \ |
369 | pre##_cfbencrypt(&g->k, s, t, sz); \ |
370 | } \ |
371 | \ |
372 | static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
373 | { \ |
374 | gctx *g = (gctx *)c; \ |
375 | pre##_cfbdecrypt(&g->k, s, t, sz); \ |
376 | } \ |
377 | \ |
378 | static void gdestroy(gcipher *c) \ |
379 | { \ |
380 | gctx *g = (gctx *)c; \ |
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381 | BURN(*g); \ |
382 | S_DESTROY(g); \ |
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383 | } \ |
384 | \ |
385 | static void gsetiv(gcipher *c, const void *iv) \ |
386 | { \ |
387 | gctx *g = (gctx *)c; \ |
388 | pre##_cfbsetiv(&g->k, iv); \ |
389 | } \ |
390 | \ |
391 | static void gbdry(gcipher *c) \ |
392 | { \ |
393 | gctx *g = (gctx *)c; \ |
394 | pre##_cfbbdry(&g->k); \ |
395 | } \ |
396 | \ |
397 | static const gcipher_ops gops = { \ |
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398 | &pre##_cfb, \ |
399 | gencrypt, gdecrypt, gdestroy, gsetiv, gbdry \ |
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400 | }; \ |
401 | \ |
402 | const gccipher pre##_cfb = { \ |
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403 | #pre "-cfb", pre##_keysz, PRE##_BLKSZ, \ |
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404 | ginit \ |
405 | }; \ |
406 | \ |
407 | CFB_TEST(PRE, pre) |
408 | |
409 | /*----- Test rig ----------------------------------------------------------*/ |
410 | |
411 | #ifdef TEST_RIG |
412 | |
413 | #include <stdio.h> |
414 | |
415 | #include "daftstory.h" |
416 | |
417 | /* --- @CFB_TEST@ --- * |
418 | * |
419 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
420 | * |
421 | * Use: Standard test rig for CFB functions. |
422 | */ |
423 | |
424 | #define CFB_TEST(PRE, pre) \ |
425 | \ |
426 | /* --- Initial plaintext for the test --- */ \ |
427 | \ |
428 | static const octet text[] = TEXT; \ |
429 | \ |
430 | /* --- Key and IV to use --- */ \ |
431 | \ |
432 | static const octet key[] = KEY; \ |
433 | static const octet iv[] = IV; \ |
434 | \ |
435 | /* --- Buffers for encryption and decryption output --- */ \ |
436 | \ |
437 | static octet ct[sizeof(text)]; \ |
438 | static octet pt[sizeof(text)]; \ |
439 | \ |
440 | static void hexdump(const octet *p, size_t sz) \ |
441 | { \ |
442 | const octet *q = p + sz; \ |
443 | for (sz = 0; p < q; p++, sz++) { \ |
444 | printf("%02x", *p); \ |
445 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
446 | putchar(':'); \ |
447 | } \ |
448 | } \ |
449 | \ |
450 | int main(void) \ |
451 | { \ |
452 | size_t sz = 0, rest; \ |
453 | pre##_cfbctx ctx; \ |
454 | int status = 0; \ |
455 | int done = 0; \ |
456 | pre##_ctx k; \ |
457 | \ |
458 | size_t keysz = PRE##_KEYSZ ? \ |
459 | PRE##_KEYSZ : strlen((const char *)key); \ |
460 | \ |
461 | fputs(#pre "-cfb: ", stdout); \ |
462 | \ |
463 | pre##_init(&k, key, keysz); \ |
464 | pre##_cfbsetkey(&ctx, &k); \ |
465 | \ |
466 | while (sz <= sizeof(text)) { \ |
467 | rest = sizeof(text) - sz; \ |
468 | memcpy(ct, text, sizeof(text)); \ |
469 | pre##_cfbsetiv(&ctx, iv); \ |
470 | pre##_cfbencrypt(&ctx, ct, ct, sz); \ |
471 | pre##_cfbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
472 | memcpy(pt, ct, sizeof(text)); \ |
473 | pre##_cfbsetiv(&ctx, iv); \ |
474 | pre##_cfbdecrypt(&ctx, pt, pt, rest); \ |
475 | pre##_cfbdecrypt(&ctx, pt + rest, pt + rest, sz); \ |
476 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
477 | done++; \ |
478 | if (sizeof(text) < 40 || done % 8 == 0) \ |
479 | fputc('.', stdout); \ |
480 | if (done % 480 == 0) \ |
481 | fputs("\n\t", stdout); \ |
482 | fflush(stdout); \ |
483 | } else { \ |
484 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
485 | status = 1; \ |
486 | printf("\tplaintext = "); hexdump(text, sz); \ |
487 | printf(", "); hexdump(text + sz, rest); \ |
488 | fputc('\n', stdout); \ |
489 | printf("\tciphertext = "); hexdump(ct, sz); \ |
490 | printf(", "); hexdump(ct + sz, rest); \ |
491 | fputc('\n', stdout); \ |
492 | printf("\trecovered text = "); hexdump(pt, sz); \ |
493 | printf(", "); hexdump(pt + sz, rest); \ |
494 | fputc('\n', stdout); \ |
495 | fputc('\n', stdout); \ |
496 | } \ |
497 | if (sz < 63) \ |
498 | sz++; \ |
499 | else \ |
500 | sz += 9; \ |
501 | } \ |
502 | \ |
503 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
504 | return (status); \ |
505 | } |
506 | |
507 | #else |
508 | # define CFB_TEST(PRE, pre) |
509 | #endif |
510 | |
511 | /*----- That's all, folks -------------------------------------------------*/ |
512 | |
513 | #ifdef __cplusplus |
514 | } |
515 | #endif |
516 | |
517 | #endif |