79ba130c |
1 | /* -*-c-*- |
2 | * |
5c3f75ec |
3 | * $Id: cfb-def.h,v 1.6 2004/04/17 09:58:37 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 | |
79ba130c |
30 | #ifndef CATACOMB_CFB_DEF_H |
31 | #define CATACOMB_CFB_DEF_H |
32 | |
33 | #ifdef __cplusplus |
34 | extern "C" { |
35 | #endif |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #include <string.h> |
40 | |
41 | #include <mLib/bits.h> |
42 | #include <mLib/sub.h> |
43 | |
426aab6b |
44 | #ifndef CATACOMB_ARENA_H |
45 | # include "arena.h" |
46 | #endif |
47 | |
79ba130c |
48 | #ifndef CATACOMB_BLKC_H |
49 | # include "blkc.h" |
50 | #endif |
51 | |
52 | #ifndef CATACOMB_GCIPHER_H |
53 | # include "gcipher.h" |
54 | #endif |
55 | |
56 | #ifndef CATACOMB_PARANOIA_H |
57 | # include "paranoia.h" |
58 | #endif |
59 | |
426aab6b |
60 | #ifndef CATACOMB_PARANOIA_H |
61 | # include "paranoia.h" |
62 | #endif |
63 | |
79ba130c |
64 | /*----- Macros ------------------------------------------------------------*/ |
65 | |
66 | /* --- @CFB_DEF@ --- * |
67 | * |
68 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
69 | * |
70 | * Use: Creates an implementation for CFB mode. |
71 | */ |
72 | |
73 | #define CFB_DEF(PRE, pre) \ |
74 | \ |
75 | /* --- @pre_cfbgetiv@ --- * \ |
76 | * \ |
77 | * Arguments: @const pre_cfbctx *ctx@ = pointer to CFB context block \ |
4efe32ba |
78 | * @void *iv@ = pointer to output data block \ |
79ba130c |
79 | * \ |
80 | * Returns: --- \ |
81 | * \ |
82 | * Use: Reads the currently set IV. Reading and setting an IV \ |
83 | * is not transparent to the cipher. It will add a `step' \ |
84 | * which must be matched by a similar operation during \ |
85 | * decryption. \ |
86 | */ \ |
87 | \ |
88 | void pre##_cfbgetiv(const pre##_cfbctx *ctx, void *iv) \ |
89 | { \ |
90 | octet *p = iv; \ |
426aab6b |
91 | unsigned off = ctx->off; \ |
92 | unsigned rest = PRE##_BLKSZ - off; \ |
79ba130c |
93 | memcpy(p, ctx->iv + off, rest); \ |
94 | memcpy(p + rest, ctx->iv, off); \ |
95 | } \ |
96 | \ |
97 | /* --- @pre_cfbsetiv@ --- * \ |
98 | * \ |
99 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
100 | * @cnost void *iv@ = pointer to IV to set \ |
101 | * \ |
102 | * Returns: --- \ |
103 | * \ |
104 | * Use: Sets the IV to use for subsequent encryption. \ |
105 | */ \ |
106 | \ |
107 | void pre##_cfbsetiv(pre##_cfbctx *ctx, const void *iv) \ |
108 | { \ |
426aab6b |
109 | memcpy(ctx->iv, iv, PRE##_BLKSZ); \ |
110 | ctx->off = PRE##_BLKSZ; \ |
79ba130c |
111 | } \ |
112 | \ |
113 | /* --- @pre_cfbbdry@ --- * \ |
114 | * \ |
115 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
116 | * \ |
117 | * Returns: --- \ |
118 | * \ |
119 | * Use: Inserts a boundary during encryption. Successful \ |
120 | * decryption must place a similar boundary. \ |
121 | */ \ |
122 | \ |
123 | void pre##_cfbbdry(pre##_cfbctx *ctx) \ |
124 | { \ |
426aab6b |
125 | uint32 niv[PRE##_BLKSZ / 4]; \ |
126 | BLKC_LOAD(PRE, niv, ctx->iv); \ |
127 | pre##_eblk(&ctx->ctx, niv, niv); \ |
128 | BLKC_STORE(PRE, ctx->iv, niv); \ |
129 | ctx->off = PRE##_BLKSZ; \ |
130 | BURN(niv); \ |
79ba130c |
131 | } \ |
132 | \ |
133 | /* --- @pre_cfbsetkey@ --- * \ |
134 | * \ |
135 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
136 | * @const pre_ctx *k@ = pointer to cipher context \ |
137 | * \ |
138 | * Returns: --- \ |
139 | * \ |
140 | * Use: Sets the CFB context to use a different cipher key. \ |
141 | */ \ |
142 | \ |
143 | void pre##_cfbsetkey(pre##_cfbctx *ctx, const pre##_ctx *k) \ |
144 | { \ |
145 | ctx->ctx = *k; \ |
426aab6b |
146 | ctx->off = PRE##_BLKSZ; \ |
79ba130c |
147 | } \ |
148 | \ |
149 | /* --- @pre_cfbinit@ --- * \ |
150 | * \ |
151 | * Arguments: @pre_cfbctx *ctx@ = pointer to cipher context \ |
152 | * @const void *key@ = pointer to the key buffer \ |
153 | * @size_t sz@ = size of the key \ |
154 | * @const void *iv@ = pointer to initialization vector \ |
155 | * \ |
156 | * Returns: --- \ |
157 | * \ |
158 | * Use: Initializes a CFB context ready for use. You should \ |
159 | * ensure that the IV chosen is unique: reusing an IV will \ |
160 | * compromise the security of at least the first block \ |
161 | * encrypted. This is equivalent to calls to @pre_init@, \ |
162 | * @pre_cfbsetkey@ and @pre_cfbsetiv@. \ |
163 | */ \ |
164 | \ |
165 | void pre##_cfbinit(pre##_cfbctx *ctx, \ |
166 | const void *key, size_t sz, \ |
167 | const void *iv) \ |
168 | { \ |
4e66da02 |
169 | static const octet zero[PRE##_BLKSZ] = { 0 }; \ |
79ba130c |
170 | pre##_init(&ctx->ctx, key, sz); \ |
171 | pre##_cfbsetiv(ctx, iv ? iv : zero); \ |
172 | } \ |
173 | \ |
174 | /* --- @pre_cfbencrypt@ --- * \ |
175 | * \ |
176 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
177 | * @const void *src@ = pointer to source data \ |
178 | * @void *dest@ = pointer to destination data \ |
179 | * @size_t sz@ = size of block to be encrypted \ |
180 | * \ |
181 | * Returns: --- \ |
182 | * \ |
183 | * Use: Encrypts a block with a block cipher in CFB mode. The \ |
184 | * input block may be arbitrary in size. CFB mode is not \ |
185 | * sensitive to block boundaries. \ |
186 | */ \ |
187 | \ |
188 | void pre##_cfbencrypt(pre##_cfbctx *ctx, \ |
189 | const void *src, void *dest, \ |
190 | size_t sz) \ |
191 | { \ |
192 | const octet *s = src; \ |
193 | octet *d = dest; \ |
426aab6b |
194 | unsigned off = ctx->off; \ |
79ba130c |
195 | \ |
196 | /* --- Empty blocks are trivial --- */ \ |
197 | \ |
198 | if (!sz) \ |
199 | return; \ |
200 | \ |
201 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
202 | \ |
203 | if (sz < PRE##_BLKSZ - off) \ |
204 | goto small; \ |
205 | \ |
206 | /* --- Finish off what's left in my buffer --- */ \ |
207 | \ |
208 | while (off < PRE##_BLKSZ) { \ |
209 | register octet x = *s++; \ |
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210 | ctx->iv[off] ^= x; \ |
211 | if (d) *d++ = ctx->iv[off]; \ |
212 | off++; \ |
79ba130c |
213 | sz--; \ |
214 | } \ |
215 | \ |
216 | /* --- Main encryption loop --- */ \ |
217 | \ |
218 | { \ |
219 | uint32 iv[PRE##_BLKSZ / 4]; \ |
220 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
221 | \ |
222 | for (;;) { \ |
223 | pre##_eblk(&ctx->ctx, iv, iv); \ |
224 | if (sz < PRE##_BLKSZ) \ |
225 | break; \ |
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226 | if (s) { \ |
227 | BLKC_XLOAD(PRE, iv, s); \ |
228 | s += PRE##_BLKSZ; \ |
229 | } \ |
230 | if (d) { \ |
231 | BLKC_STORE(PRE, d, iv); \ |
232 | d += PRE##_BLKSZ; \ |
233 | } \ |
79ba130c |
234 | sz -= PRE##_BLKSZ; \ |
235 | } \ |
236 | off = 0; \ |
237 | BLKC_STORE(PRE, ctx->iv, iv); \ |
238 | } \ |
239 | \ |
240 | /* --- Tidying up the tail end --- */ \ |
241 | \ |
242 | if (sz) { \ |
243 | small: \ |
244 | do { \ |
245 | register octet x = *s++; \ |
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246 | ctx->iv[off] ^= x; \ |
247 | if (d) *d++ = ctx->iv[off]; \ |
248 | off++; \ |
79ba130c |
249 | sz--; \ |
250 | } while (sz); \ |
251 | } \ |
252 | \ |
253 | /* --- Done --- */ \ |
254 | \ |
255 | ctx->off = off; \ |
256 | return; \ |
257 | } \ |
258 | \ |
426aab6b |
259 | /* --- @pre_cfbdecrypt@ --- * \ |
79ba130c |
260 | * \ |
261 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
262 | * @const void *src@ = pointer to source data \ |
263 | * @void *dest@ = pointer to destination data \ |
264 | * @size_t sz@ = size of block to be encrypted \ |
265 | * \ |
266 | * Returns: --- \ |
267 | * \ |
268 | * Use: Decrypts a block with a block cipher in CFB mode. The \ |
269 | * input block may be arbitrary in size. CFB mode is not \ |
270 | * sensitive to block boundaries. \ |
271 | */ \ |
272 | \ |
273 | void pre##_cfbdecrypt(pre##_cfbctx *ctx, \ |
274 | const void *src, void *dest, \ |
275 | size_t sz) \ |
276 | { \ |
277 | const octet *s = src; \ |
278 | octet *d = dest; \ |
426aab6b |
279 | unsigned off = ctx->off; \ |
79ba130c |
280 | \ |
281 | /* --- Empty blocks are trivial --- */ \ |
282 | \ |
283 | if (!sz) \ |
284 | return; \ |
285 | \ |
286 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
287 | \ |
288 | if (sz < PRE##_BLKSZ - off) \ |
289 | goto small; \ |
290 | \ |
291 | /* --- Finish off what's left in my buffer --- */ \ |
292 | \ |
293 | while (off < PRE##_BLKSZ) { \ |
294 | register octet x = *s++; \ |
295 | *d++ = ctx->iv[off] ^ x; \ |
296 | ctx->iv[off++] = x; \ |
297 | sz--; \ |
298 | } \ |
299 | \ |
300 | /* --- Main encryption loop --- */ \ |
301 | \ |
302 | { \ |
303 | uint32 iv[PRE##_BLKSZ / 4]; \ |
304 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
305 | \ |
306 | for (;;) { \ |
307 | uint32 x[PRE##_BLKSZ / 4]; \ |
308 | pre##_eblk(&ctx->ctx, iv, iv); \ |
309 | if (sz < PRE##_BLKSZ) \ |
310 | break; \ |
311 | BLKC_LOAD(PRE, x, s); \ |
312 | BLKC_XSTORE(PRE, d, iv, x); \ |
313 | BLKC_MOVE(PRE, iv, x); \ |
314 | s += PRE##_BLKSZ; \ |
315 | d += PRE##_BLKSZ; \ |
316 | sz -= PRE##_BLKSZ; \ |
317 | } \ |
318 | off = 0; \ |
319 | BLKC_STORE(PRE, ctx->iv, iv); \ |
320 | } \ |
321 | \ |
322 | /* --- Tidying up the tail end --- */ \ |
323 | \ |
324 | if (sz) { \ |
325 | small: \ |
326 | do { \ |
327 | register octet x = *s++; \ |
328 | *d++ = ctx->iv[off] ^ x; \ |
329 | ctx->iv[off++] = x; \ |
330 | sz--; \ |
331 | } while (sz); \ |
332 | } \ |
333 | \ |
334 | /* --- Done --- */ \ |
335 | \ |
336 | ctx->off = off; \ |
337 | return; \ |
338 | } \ |
339 | \ |
340 | /* --- Generic cipher interface --- */ \ |
341 | \ |
342 | static const gcipher_ops gops; \ |
343 | \ |
344 | typedef struct gctx { \ |
345 | gcipher c; \ |
346 | pre##_cfbctx k; \ |
347 | } gctx; \ |
348 | \ |
349 | static gcipher *ginit(const void *k, size_t sz) \ |
350 | { \ |
426aab6b |
351 | gctx *g = S_CREATE(gctx); \ |
79ba130c |
352 | g->c.ops = &gops; \ |
353 | pre##_cfbinit(&g->k, k, sz, 0); \ |
354 | return (&g->c); \ |
355 | } \ |
356 | \ |
357 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
358 | { \ |
359 | gctx *g = (gctx *)c; \ |
360 | pre##_cfbencrypt(&g->k, s, t, sz); \ |
361 | } \ |
362 | \ |
363 | static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
364 | { \ |
365 | gctx *g = (gctx *)c; \ |
366 | pre##_cfbdecrypt(&g->k, s, t, sz); \ |
367 | } \ |
368 | \ |
369 | static void gdestroy(gcipher *c) \ |
370 | { \ |
371 | gctx *g = (gctx *)c; \ |
426aab6b |
372 | BURN(*g); \ |
373 | S_DESTROY(g); \ |
79ba130c |
374 | } \ |
375 | \ |
376 | static void gsetiv(gcipher *c, const void *iv) \ |
377 | { \ |
378 | gctx *g = (gctx *)c; \ |
379 | pre##_cfbsetiv(&g->k, iv); \ |
380 | } \ |
381 | \ |
382 | static void gbdry(gcipher *c) \ |
383 | { \ |
384 | gctx *g = (gctx *)c; \ |
385 | pre##_cfbbdry(&g->k); \ |
386 | } \ |
387 | \ |
388 | static const gcipher_ops gops = { \ |
426aab6b |
389 | &pre##_cfb, \ |
390 | gencrypt, gdecrypt, gdestroy, gsetiv, gbdry \ |
79ba130c |
391 | }; \ |
392 | \ |
393 | const gccipher pre##_cfb = { \ |
426aab6b |
394 | #pre "-cfb", pre##_keysz, PRE##_BLKSZ, \ |
79ba130c |
395 | ginit \ |
396 | }; \ |
397 | \ |
398 | CFB_TEST(PRE, pre) |
399 | |
400 | /*----- Test rig ----------------------------------------------------------*/ |
401 | |
402 | #ifdef TEST_RIG |
403 | |
404 | #include <stdio.h> |
405 | |
406 | #include "daftstory.h" |
407 | |
408 | /* --- @CFB_TEST@ --- * |
409 | * |
410 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
411 | * |
412 | * Use: Standard test rig for CFB functions. |
413 | */ |
414 | |
415 | #define CFB_TEST(PRE, pre) \ |
416 | \ |
417 | /* --- Initial plaintext for the test --- */ \ |
418 | \ |
419 | static const octet text[] = TEXT; \ |
420 | \ |
421 | /* --- Key and IV to use --- */ \ |
422 | \ |
423 | static const octet key[] = KEY; \ |
424 | static const octet iv[] = IV; \ |
425 | \ |
426 | /* --- Buffers for encryption and decryption output --- */ \ |
427 | \ |
428 | static octet ct[sizeof(text)]; \ |
429 | static octet pt[sizeof(text)]; \ |
430 | \ |
431 | static void hexdump(const octet *p, size_t sz) \ |
432 | { \ |
433 | const octet *q = p + sz; \ |
434 | for (sz = 0; p < q; p++, sz++) { \ |
435 | printf("%02x", *p); \ |
436 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
437 | putchar(':'); \ |
438 | } \ |
439 | } \ |
440 | \ |
441 | int main(void) \ |
442 | { \ |
443 | size_t sz = 0, rest; \ |
444 | pre##_cfbctx ctx; \ |
445 | int status = 0; \ |
446 | int done = 0; \ |
447 | pre##_ctx k; \ |
448 | \ |
449 | size_t keysz = PRE##_KEYSZ ? \ |
450 | PRE##_KEYSZ : strlen((const char *)key); \ |
451 | \ |
452 | fputs(#pre "-cfb: ", stdout); \ |
453 | \ |
454 | pre##_init(&k, key, keysz); \ |
455 | pre##_cfbsetkey(&ctx, &k); \ |
456 | \ |
457 | while (sz <= sizeof(text)) { \ |
458 | rest = sizeof(text) - sz; \ |
459 | memcpy(ct, text, sizeof(text)); \ |
460 | pre##_cfbsetiv(&ctx, iv); \ |
461 | pre##_cfbencrypt(&ctx, ct, ct, sz); \ |
462 | pre##_cfbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
463 | memcpy(pt, ct, sizeof(text)); \ |
464 | pre##_cfbsetiv(&ctx, iv); \ |
465 | pre##_cfbdecrypt(&ctx, pt, pt, rest); \ |
466 | pre##_cfbdecrypt(&ctx, pt + rest, pt + rest, sz); \ |
467 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
468 | done++; \ |
469 | if (sizeof(text) < 40 || done % 8 == 0) \ |
470 | fputc('.', stdout); \ |
471 | if (done % 480 == 0) \ |
472 | fputs("\n\t", stdout); \ |
473 | fflush(stdout); \ |
474 | } else { \ |
475 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
476 | status = 1; \ |
477 | printf("\tplaintext = "); hexdump(text, sz); \ |
478 | printf(", "); hexdump(text + sz, rest); \ |
479 | fputc('\n', stdout); \ |
480 | printf("\tciphertext = "); hexdump(ct, sz); \ |
481 | printf(", "); hexdump(ct + sz, rest); \ |
482 | fputc('\n', stdout); \ |
483 | printf("\trecovered text = "); hexdump(pt, sz); \ |
484 | printf(", "); hexdump(pt + sz, rest); \ |
485 | fputc('\n', stdout); \ |
486 | fputc('\n', stdout); \ |
487 | } \ |
488 | if (sz < 63) \ |
489 | sz++; \ |
490 | else \ |
491 | sz += 9; \ |
492 | } \ |
493 | \ |
494 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
495 | return (status); \ |
496 | } |
497 | |
498 | #else |
499 | # define CFB_TEST(PRE, pre) |
500 | #endif |
501 | |
502 | /*----- That's all, folks -------------------------------------------------*/ |
503 | |
504 | #ifdef __cplusplus |
505 | } |
506 | #endif |
507 | |
508 | #endif |