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1 | /* -*-c-*- |
2 | * |
4efe32ba |
3 | * $Id: cfb-def.h,v 1.3 2001/06/17 00:10:51 mdw Exp $ |
79ba130c |
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 $ |
4efe32ba |
33 | * Revision 1.3 2001/06/17 00:10:51 mdw |
34 | * Typesetting fixes |
35 | * |
426aab6b |
36 | * Revision 1.2 2000/06/17 10:50:39 mdw |
37 | * Use secure arena for memory allocation. Rearrange setiv slightly. |
38 | * |
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39 | * Revision 1.1 1999/12/10 23:16:39 mdw |
40 | * Split mode macros into interface and implementation. |
41 | * |
42 | */ |
43 | |
44 | #ifndef CATACOMB_CFB_DEF_H |
45 | #define CATACOMB_CFB_DEF_H |
46 | |
47 | #ifdef __cplusplus |
48 | extern "C" { |
49 | #endif |
50 | |
51 | /*----- Header files ------------------------------------------------------*/ |
52 | |
53 | #include <string.h> |
54 | |
55 | #include <mLib/bits.h> |
56 | #include <mLib/sub.h> |
57 | |
426aab6b |
58 | #ifndef CATACOMB_ARENA_H |
59 | # include "arena.h" |
60 | #endif |
61 | |
79ba130c |
62 | #ifndef CATACOMB_BLKC_H |
63 | # include "blkc.h" |
64 | #endif |
65 | |
66 | #ifndef CATACOMB_GCIPHER_H |
67 | # include "gcipher.h" |
68 | #endif |
69 | |
70 | #ifndef CATACOMB_PARANOIA_H |
71 | # include "paranoia.h" |
72 | #endif |
73 | |
426aab6b |
74 | #ifndef CATACOMB_PARANOIA_H |
75 | # include "paranoia.h" |
76 | #endif |
77 | |
79ba130c |
78 | /*----- Macros ------------------------------------------------------------*/ |
79 | |
80 | /* --- @CFB_DEF@ --- * |
81 | * |
82 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
83 | * |
84 | * Use: Creates an implementation for CFB mode. |
85 | */ |
86 | |
87 | #define CFB_DEF(PRE, pre) \ |
88 | \ |
89 | /* --- @pre_cfbgetiv@ --- * \ |
90 | * \ |
91 | * Arguments: @const pre_cfbctx *ctx@ = pointer to CFB context block \ |
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92 | * @void *iv@ = pointer to output data block \ |
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93 | * \ |
94 | * Returns: --- \ |
95 | * \ |
96 | * Use: Reads the currently set IV. Reading and setting an IV \ |
97 | * is not transparent to the cipher. It will add a `step' \ |
98 | * which must be matched by a similar operation during \ |
99 | * decryption. \ |
100 | */ \ |
101 | \ |
102 | void pre##_cfbgetiv(const pre##_cfbctx *ctx, void *iv) \ |
103 | { \ |
104 | octet *p = iv; \ |
426aab6b |
105 | unsigned off = ctx->off; \ |
106 | unsigned rest = PRE##_BLKSZ - off; \ |
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107 | memcpy(p, ctx->iv + off, rest); \ |
108 | memcpy(p + rest, ctx->iv, off); \ |
109 | } \ |
110 | \ |
111 | /* --- @pre_cfbsetiv@ --- * \ |
112 | * \ |
113 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
114 | * @cnost void *iv@ = pointer to IV to set \ |
115 | * \ |
116 | * Returns: --- \ |
117 | * \ |
118 | * Use: Sets the IV to use for subsequent encryption. \ |
119 | */ \ |
120 | \ |
121 | void pre##_cfbsetiv(pre##_cfbctx *ctx, const void *iv) \ |
122 | { \ |
426aab6b |
123 | memcpy(ctx->iv, iv, PRE##_BLKSZ); \ |
124 | ctx->off = PRE##_BLKSZ; \ |
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125 | } \ |
126 | \ |
127 | /* --- @pre_cfbbdry@ --- * \ |
128 | * \ |
129 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
130 | * \ |
131 | * Returns: --- \ |
132 | * \ |
133 | * Use: Inserts a boundary during encryption. Successful \ |
134 | * decryption must place a similar boundary. \ |
135 | */ \ |
136 | \ |
137 | void pre##_cfbbdry(pre##_cfbctx *ctx) \ |
138 | { \ |
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139 | uint32 niv[PRE##_BLKSZ / 4]; \ |
140 | BLKC_LOAD(PRE, niv, ctx->iv); \ |
141 | pre##_eblk(&ctx->ctx, niv, niv); \ |
142 | BLKC_STORE(PRE, ctx->iv, niv); \ |
143 | ctx->off = PRE##_BLKSZ; \ |
144 | BURN(niv); \ |
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145 | } \ |
146 | \ |
147 | /* --- @pre_cfbsetkey@ --- * \ |
148 | * \ |
149 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
150 | * @const pre_ctx *k@ = pointer to cipher context \ |
151 | * \ |
152 | * Returns: --- \ |
153 | * \ |
154 | * Use: Sets the CFB context to use a different cipher key. \ |
155 | */ \ |
156 | \ |
157 | void pre##_cfbsetkey(pre##_cfbctx *ctx, const pre##_ctx *k) \ |
158 | { \ |
159 | ctx->ctx = *k; \ |
426aab6b |
160 | ctx->off = PRE##_BLKSZ; \ |
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161 | } \ |
162 | \ |
163 | /* --- @pre_cfbinit@ --- * \ |
164 | * \ |
165 | * Arguments: @pre_cfbctx *ctx@ = pointer to cipher context \ |
166 | * @const void *key@ = pointer to the key buffer \ |
167 | * @size_t sz@ = size of the key \ |
168 | * @const void *iv@ = pointer to initialization vector \ |
169 | * \ |
170 | * Returns: --- \ |
171 | * \ |
172 | * Use: Initializes a CFB context ready for use. You should \ |
173 | * ensure that the IV chosen is unique: reusing an IV will \ |
174 | * compromise the security of at least the first block \ |
175 | * encrypted. This is equivalent to calls to @pre_init@, \ |
176 | * @pre_cfbsetkey@ and @pre_cfbsetiv@. \ |
177 | */ \ |
178 | \ |
179 | void pre##_cfbinit(pre##_cfbctx *ctx, \ |
180 | const void *key, size_t sz, \ |
181 | const void *iv) \ |
182 | { \ |
183 | static octet zero[PRE##_BLKSZ] = { 0 }; \ |
184 | pre##_init(&ctx->ctx, key, sz); \ |
185 | pre##_cfbsetiv(ctx, iv ? iv : zero); \ |
186 | } \ |
187 | \ |
188 | /* --- @pre_cfbencrypt@ --- * \ |
189 | * \ |
190 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
191 | * @const void *src@ = pointer to source data \ |
192 | * @void *dest@ = pointer to destination data \ |
193 | * @size_t sz@ = size of block to be encrypted \ |
194 | * \ |
195 | * Returns: --- \ |
196 | * \ |
197 | * Use: Encrypts a block with a block cipher in CFB mode. The \ |
198 | * input block may be arbitrary in size. CFB mode is not \ |
199 | * sensitive to block boundaries. \ |
200 | */ \ |
201 | \ |
202 | void pre##_cfbencrypt(pre##_cfbctx *ctx, \ |
203 | const void *src, void *dest, \ |
204 | size_t sz) \ |
205 | { \ |
206 | const octet *s = src; \ |
207 | octet *d = dest; \ |
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208 | unsigned off = ctx->off; \ |
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209 | \ |
210 | /* --- Empty blocks are trivial --- */ \ |
211 | \ |
212 | if (!sz) \ |
213 | return; \ |
214 | \ |
215 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
216 | \ |
217 | if (sz < PRE##_BLKSZ - off) \ |
218 | goto small; \ |
219 | \ |
220 | /* --- Finish off what's left in my buffer --- */ \ |
221 | \ |
222 | while (off < PRE##_BLKSZ) { \ |
223 | register octet x = *s++; \ |
224 | *d++ = ctx->iv[off++] ^= x; \ |
225 | sz--; \ |
226 | } \ |
227 | \ |
228 | /* --- Main encryption loop --- */ \ |
229 | \ |
230 | { \ |
231 | uint32 iv[PRE##_BLKSZ / 4]; \ |
232 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
233 | \ |
234 | for (;;) { \ |
235 | pre##_eblk(&ctx->ctx, iv, iv); \ |
236 | if (sz < PRE##_BLKSZ) \ |
237 | break; \ |
238 | BLKC_XLOAD(PRE, iv, s); \ |
239 | BLKC_STORE(PRE, d, iv); \ |
240 | s += PRE##_BLKSZ; \ |
241 | d += PRE##_BLKSZ; \ |
242 | sz -= PRE##_BLKSZ; \ |
243 | } \ |
244 | off = 0; \ |
245 | BLKC_STORE(PRE, ctx->iv, iv); \ |
246 | } \ |
247 | \ |
248 | /* --- Tidying up the tail end --- */ \ |
249 | \ |
250 | if (sz) { \ |
251 | small: \ |
252 | do { \ |
253 | register octet x = *s++; \ |
254 | *d++ = ctx->iv[off++] ^= x; \ |
255 | sz--; \ |
256 | } while (sz); \ |
257 | } \ |
258 | \ |
259 | /* --- Done --- */ \ |
260 | \ |
261 | ctx->off = off; \ |
262 | return; \ |
263 | } \ |
264 | \ |
426aab6b |
265 | /* --- @pre_cfbdecrypt@ --- * \ |
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266 | * \ |
267 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
268 | * @const void *src@ = pointer to source data \ |
269 | * @void *dest@ = pointer to destination data \ |
270 | * @size_t sz@ = size of block to be encrypted \ |
271 | * \ |
272 | * Returns: --- \ |
273 | * \ |
274 | * Use: Decrypts a block with a block cipher in CFB mode. The \ |
275 | * input block may be arbitrary in size. CFB mode is not \ |
276 | * sensitive to block boundaries. \ |
277 | */ \ |
278 | \ |
279 | void pre##_cfbdecrypt(pre##_cfbctx *ctx, \ |
280 | const void *src, void *dest, \ |
281 | size_t sz) \ |
282 | { \ |
283 | const octet *s = src; \ |
284 | octet *d = dest; \ |
426aab6b |
285 | unsigned off = ctx->off; \ |
79ba130c |
286 | \ |
287 | /* --- Empty blocks are trivial --- */ \ |
288 | \ |
289 | if (!sz) \ |
290 | return; \ |
291 | \ |
292 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
293 | \ |
294 | if (sz < PRE##_BLKSZ - off) \ |
295 | goto small; \ |
296 | \ |
297 | /* --- Finish off what's left in my buffer --- */ \ |
298 | \ |
299 | while (off < PRE##_BLKSZ) { \ |
300 | register octet x = *s++; \ |
301 | *d++ = ctx->iv[off] ^ x; \ |
302 | ctx->iv[off++] = x; \ |
303 | sz--; \ |
304 | } \ |
305 | \ |
306 | /* --- Main encryption loop --- */ \ |
307 | \ |
308 | { \ |
309 | uint32 iv[PRE##_BLKSZ / 4]; \ |
310 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
311 | \ |
312 | for (;;) { \ |
313 | uint32 x[PRE##_BLKSZ / 4]; \ |
314 | pre##_eblk(&ctx->ctx, iv, iv); \ |
315 | if (sz < PRE##_BLKSZ) \ |
316 | break; \ |
317 | BLKC_LOAD(PRE, x, s); \ |
318 | BLKC_XSTORE(PRE, d, iv, x); \ |
319 | BLKC_MOVE(PRE, iv, x); \ |
320 | s += PRE##_BLKSZ; \ |
321 | d += PRE##_BLKSZ; \ |
322 | sz -= PRE##_BLKSZ; \ |
323 | } \ |
324 | off = 0; \ |
325 | BLKC_STORE(PRE, ctx->iv, iv); \ |
326 | } \ |
327 | \ |
328 | /* --- Tidying up the tail end --- */ \ |
329 | \ |
330 | if (sz) { \ |
331 | small: \ |
332 | do { \ |
333 | register octet x = *s++; \ |
334 | *d++ = ctx->iv[off] ^ x; \ |
335 | ctx->iv[off++] = x; \ |
336 | sz--; \ |
337 | } while (sz); \ |
338 | } \ |
339 | \ |
340 | /* --- Done --- */ \ |
341 | \ |
342 | ctx->off = off; \ |
343 | return; \ |
344 | } \ |
345 | \ |
346 | /* --- Generic cipher interface --- */ \ |
347 | \ |
348 | static const gcipher_ops gops; \ |
349 | \ |
350 | typedef struct gctx { \ |
351 | gcipher c; \ |
352 | pre##_cfbctx k; \ |
353 | } gctx; \ |
354 | \ |
355 | static gcipher *ginit(const void *k, size_t sz) \ |
356 | { \ |
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357 | gctx *g = S_CREATE(gctx); \ |
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358 | g->c.ops = &gops; \ |
359 | pre##_cfbinit(&g->k, k, sz, 0); \ |
360 | return (&g->c); \ |
361 | } \ |
362 | \ |
363 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
364 | { \ |
365 | gctx *g = (gctx *)c; \ |
366 | pre##_cfbencrypt(&g->k, s, t, sz); \ |
367 | } \ |
368 | \ |
369 | static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
370 | { \ |
371 | gctx *g = (gctx *)c; \ |
372 | pre##_cfbdecrypt(&g->k, s, t, sz); \ |
373 | } \ |
374 | \ |
375 | static void gdestroy(gcipher *c) \ |
376 | { \ |
377 | gctx *g = (gctx *)c; \ |
426aab6b |
378 | BURN(*g); \ |
379 | S_DESTROY(g); \ |
79ba130c |
380 | } \ |
381 | \ |
382 | static void gsetiv(gcipher *c, const void *iv) \ |
383 | { \ |
384 | gctx *g = (gctx *)c; \ |
385 | pre##_cfbsetiv(&g->k, iv); \ |
386 | } \ |
387 | \ |
388 | static void gbdry(gcipher *c) \ |
389 | { \ |
390 | gctx *g = (gctx *)c; \ |
391 | pre##_cfbbdry(&g->k); \ |
392 | } \ |
393 | \ |
394 | static const gcipher_ops gops = { \ |
426aab6b |
395 | &pre##_cfb, \ |
396 | gencrypt, gdecrypt, gdestroy, gsetiv, gbdry \ |
79ba130c |
397 | }; \ |
398 | \ |
399 | const gccipher pre##_cfb = { \ |
426aab6b |
400 | #pre "-cfb", pre##_keysz, PRE##_BLKSZ, \ |
79ba130c |
401 | ginit \ |
402 | }; \ |
403 | \ |
404 | CFB_TEST(PRE, pre) |
405 | |
406 | /*----- Test rig ----------------------------------------------------------*/ |
407 | |
408 | #ifdef TEST_RIG |
409 | |
410 | #include <stdio.h> |
411 | |
412 | #include "daftstory.h" |
413 | |
414 | /* --- @CFB_TEST@ --- * |
415 | * |
416 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
417 | * |
418 | * Use: Standard test rig for CFB functions. |
419 | */ |
420 | |
421 | #define CFB_TEST(PRE, pre) \ |
422 | \ |
423 | /* --- Initial plaintext for the test --- */ \ |
424 | \ |
425 | static const octet text[] = TEXT; \ |
426 | \ |
427 | /* --- Key and IV to use --- */ \ |
428 | \ |
429 | static const octet key[] = KEY; \ |
430 | static const octet iv[] = IV; \ |
431 | \ |
432 | /* --- Buffers for encryption and decryption output --- */ \ |
433 | \ |
434 | static octet ct[sizeof(text)]; \ |
435 | static octet pt[sizeof(text)]; \ |
436 | \ |
437 | static void hexdump(const octet *p, size_t sz) \ |
438 | { \ |
439 | const octet *q = p + sz; \ |
440 | for (sz = 0; p < q; p++, sz++) { \ |
441 | printf("%02x", *p); \ |
442 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
443 | putchar(':'); \ |
444 | } \ |
445 | } \ |
446 | \ |
447 | int main(void) \ |
448 | { \ |
449 | size_t sz = 0, rest; \ |
450 | pre##_cfbctx ctx; \ |
451 | int status = 0; \ |
452 | int done = 0; \ |
453 | pre##_ctx k; \ |
454 | \ |
455 | size_t keysz = PRE##_KEYSZ ? \ |
456 | PRE##_KEYSZ : strlen((const char *)key); \ |
457 | \ |
458 | fputs(#pre "-cfb: ", stdout); \ |
459 | \ |
460 | pre##_init(&k, key, keysz); \ |
461 | pre##_cfbsetkey(&ctx, &k); \ |
462 | \ |
463 | while (sz <= sizeof(text)) { \ |
464 | rest = sizeof(text) - sz; \ |
465 | memcpy(ct, text, sizeof(text)); \ |
466 | pre##_cfbsetiv(&ctx, iv); \ |
467 | pre##_cfbencrypt(&ctx, ct, ct, sz); \ |
468 | pre##_cfbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
469 | memcpy(pt, ct, sizeof(text)); \ |
470 | pre##_cfbsetiv(&ctx, iv); \ |
471 | pre##_cfbdecrypt(&ctx, pt, pt, rest); \ |
472 | pre##_cfbdecrypt(&ctx, pt + rest, pt + rest, sz); \ |
473 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
474 | done++; \ |
475 | if (sizeof(text) < 40 || done % 8 == 0) \ |
476 | fputc('.', stdout); \ |
477 | if (done % 480 == 0) \ |
478 | fputs("\n\t", stdout); \ |
479 | fflush(stdout); \ |
480 | } else { \ |
481 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
482 | status = 1; \ |
483 | printf("\tplaintext = "); hexdump(text, sz); \ |
484 | printf(", "); hexdump(text + sz, rest); \ |
485 | fputc('\n', stdout); \ |
486 | printf("\tciphertext = "); hexdump(ct, sz); \ |
487 | printf(", "); hexdump(ct + sz, rest); \ |
488 | fputc('\n', stdout); \ |
489 | printf("\trecovered text = "); hexdump(pt, sz); \ |
490 | printf(", "); hexdump(pt + sz, rest); \ |
491 | fputc('\n', stdout); \ |
492 | fputc('\n', stdout); \ |
493 | } \ |
494 | if (sz < 63) \ |
495 | sz++; \ |
496 | else \ |
497 | sz += 9; \ |
498 | } \ |
499 | \ |
500 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
501 | return (status); \ |
502 | } |
503 | |
504 | #else |
505 | # define CFB_TEST(PRE, pre) |
506 | #endif |
507 | |
508 | /*----- That's all, folks -------------------------------------------------*/ |
509 | |
510 | #ifdef __cplusplus |
511 | } |
512 | #endif |
513 | |
514 | #endif |