79ba130c |
1 | /* -*-c-*- |
2 | * |
5c3f75ec |
3 | * $Id: cbc-def.h,v 1.6 2004/04/17 09:58:36 mdw Exp $ |
79ba130c |
4 | * |
5 | * Definitions for cipher block chaining 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_CBC_DEF_H |
31 | #define CATACOMB_CBC_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 | |
99461409 |
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 | |
99461409 |
56 | #ifndef CATACOMB_PARANOIA_H |
57 | # include "paranoia.h" |
58 | #endif |
59 | |
79ba130c |
60 | /*----- Macros ------------------------------------------------------------*/ |
61 | |
62 | /* --- @CBC_DEF@ --- * |
63 | * |
64 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
65 | * |
66 | * Use: Creates an implementation for CBC stealing mode. |
67 | */ |
68 | |
69 | #define CBC_DEF(PRE, pre) \ |
70 | \ |
71 | /* --- @pre_cbcgetiv@ --- * \ |
72 | * \ |
73 | * Arguments: @const pre_cbcctx *ctx@ = pointer to CBC context block \ |
4efe32ba |
74 | * @void *iv@ = pointer to output data block \ |
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75 | * \ |
76 | * Returns: --- \ |
77 | * \ |
78 | * Use: Reads the currently set IV. Reading and setting an IV \ |
79 | * is transparent to the CBC encryption or decryption \ |
80 | * process. \ |
81 | */ \ |
82 | \ |
83 | void pre##_cbcgetiv(const pre##_cbcctx *ctx, void *iv) \ |
84 | { \ |
85 | BLKC_STORE(PRE, iv, ctx->iv); \ |
86 | } \ |
87 | \ |
88 | /* --- @pre_cbcsetiv@ --- * \ |
89 | * \ |
90 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ |
91 | * @cnost void *iv@ = pointer to IV to set \ |
92 | * \ |
93 | * Returns: --- \ |
94 | * \ |
95 | * Use: Sets the IV to use for subsequent encryption. \ |
96 | */ \ |
97 | \ |
98 | void pre##_cbcsetiv(pre##_cbcctx *ctx, const void *iv) \ |
99 | { \ |
100 | BLKC_LOAD(PRE, ctx->iv, iv); \ |
101 | } \ |
102 | \ |
103 | /* --- @pre_cbcsetkey@ --- * \ |
104 | * \ |
105 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ |
106 | * @const pre_ctx *k@ = pointer to cipher context \ |
107 | * \ |
108 | * Returns: --- \ |
109 | * \ |
110 | * Use: Sets the CBC context to use a different cipher key. \ |
111 | */ \ |
112 | \ |
113 | void pre##_cbcsetkey(pre##_cbcctx *ctx, const pre##_ctx *k) \ |
114 | { \ |
115 | ctx->ctx = *k; \ |
116 | } \ |
117 | \ |
118 | /* --- @pre_cbcinit@ --- * \ |
119 | * \ |
120 | * Arguments: @pre_cbcctx *ctx@ = pointer to cipher context \ |
121 | * @const void *key@ = pointer to the key buffer \ |
122 | * @size_t sz@ = size of the key \ |
123 | * @const void *iv@ = pointer to initialization vector \ |
124 | * \ |
125 | * Returns: --- \ |
126 | * \ |
127 | * Use: Initializes a CBC context ready for use. The @iv@ \ |
128 | * argument may be passed as a null pointer to set a zero \ |
129 | * IV. Apart from that, this call is equivalent to calls \ |
130 | * to @pre_init@, @pre_cbcsetkey@ and @pre_cbcsetiv@. \ |
131 | */ \ |
132 | \ |
133 | void pre##_cbcinit(pre##_cbcctx *ctx, \ |
134 | const void *key, size_t sz, \ |
135 | const void *iv) \ |
136 | { \ |
4e66da02 |
137 | static const octet zero[PRE##_BLKSZ] = { 0 }; \ |
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138 | pre##_init(&ctx->ctx, key, sz); \ |
139 | BLKC_LOAD(PRE, ctx->iv, iv ? iv : zero); \ |
140 | } \ |
141 | \ |
142 | /* --- @pre_cbcencrypt@ --- * \ |
143 | * \ |
144 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ |
145 | * @const void *src@ = pointer to source data \ |
146 | * @void *dest@ = pointer to destination data \ |
147 | * @size_t sz@ = size of block to be encrypted \ |
148 | * \ |
149 | * Returns: --- \ |
150 | * \ |
151 | * Use: Encrypts a block with a block cipher in CBC mode, with \ |
152 | * ciphertext stealing and other clever tricks. \ |
153 | * Essentially, data can be encrypted in arbitrary sized \ |
154 | * chunks, although decryption must use the same chunks. \ |
155 | */ \ |
156 | \ |
157 | void pre##_cbcencrypt(pre##_cbcctx *ctx, \ |
158 | const void *src, void *dest, \ |
159 | size_t sz) \ |
160 | { \ |
161 | const octet *s = src; \ |
162 | octet *d = dest; \ |
163 | \ |
164 | /* --- Empty blocks are trivial --- */ \ |
165 | \ |
166 | if (!sz) \ |
167 | return; \ |
168 | \ |
169 | /* --- Extra magical case for a short block --- * \ |
170 | * \ |
171 | * Encrypt the IV, then exclusive-or the plaintext with the octets \ |
172 | * of the encrypted IV, shifting ciphertext octets in instead. This \ |
173 | * basically switches over to CFB. \ |
174 | */ \ |
175 | \ |
176 | if (sz < PRE##_BLKSZ) { \ |
177 | octet b[PRE##_BLKSZ]; \ |
178 | unsigned i; \ |
179 | \ |
180 | pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \ |
181 | BLKC_STORE(PRE, b, ctx->iv); \ |
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182 | if (d) { \ |
183 | for (i = 0; i < sz; i++) \ |
184 | d[i] = b[i] ^ (s ? s[i] : 0); \ |
185 | } \ |
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186 | memmove(b, b + sz, PRE##_BLKSZ - sz); \ |
187 | memcpy(b + PRE##_BLKSZ - sz, d, sz); \ |
188 | BLKC_LOAD(PRE, ctx->iv, b); \ |
189 | return; \ |
190 | } \ |
191 | \ |
192 | /* --- Do the main chunk of encryption --- * \ |
193 | * \ |
194 | * This will do the whole lot if it's a whole number of blocks. For \ |
195 | * each block, XOR it with the previous ciphertext in @iv@, encrypt, \ |
196 | * and keep a copy of the ciphertext for the next block. \ |
197 | */ \ |
198 | \ |
199 | while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) { \ |
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200 | if (s) { \ |
201 | BLKC_XLOAD(PRE, ctx->iv, s); \ |
202 | s += PRE##_BLKSZ; \ |
203 | } \ |
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204 | pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \ |
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205 | if (d) { \ |
206 | BLKC_STORE(PRE, d, ctx->iv); \ |
207 | d += PRE##_BLKSZ; \ |
208 | } \ |
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209 | sz -= PRE##_BLKSZ; \ |
210 | } \ |
211 | \ |
212 | /* --- Do the tail-end block and bit-left-over --- * \ |
213 | * \ |
214 | * This isn't very efficient. That shouldn't matter much. \ |
215 | */ \ |
216 | \ |
217 | if (sz) { \ |
218 | octet b[PRE##_BLKSZ]; \ |
219 | unsigned i; \ |
220 | \ |
221 | /* --- Let @sz@ be the size of the partial block --- */ \ |
222 | \ |
223 | sz -= PRE##_BLKSZ; \ |
224 | \ |
225 | /* --- First stage --- * \ |
226 | * \ |
227 | * XOR the complete block with the current IV, and encrypt it. The \ |
228 | * first part of the result is the partial ciphertext block. Don't \ |
229 | * write that out yet, because I've not read the partial plaintext \ |
230 | * block. \ |
231 | */ \ |
232 | \ |
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233 | if (s) BLKC_XLOAD(PRE, ctx->iv, s); \ |
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234 | pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \ |
235 | BLKC_STORE(PRE, b, ctx->iv); \ |
236 | \ |
237 | /* --- Second stage --- * \ |
238 | * \ |
239 | * Now XOR in the partial plaintext block, writing out the \ |
240 | * ciphertext as I go. Then encrypt, and write the complete \ |
241 | * ciphertext block. \ |
242 | */ \ |
243 | \ |
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244 | if (s) s += PRE##_BLKSZ; \ |
245 | if (d) d += PRE##_BLKSZ; \ |
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246 | for (i = 0; i < sz; i++) { \ |
247 | register octet x = b[i]; \ |
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248 | if (s) b[i] ^= s[i]; \ |
249 | if (d) d[i] = x; \ |
79ba130c |
250 | } \ |
251 | BLKC_LOAD(PRE, ctx->iv, b); \ |
252 | pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \ |
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253 | if (d) BLKC_STORE(PRE, d - PRE##_BLKSZ, ctx->iv); \ |
79ba130c |
254 | } \ |
255 | \ |
256 | /* --- Done --- */ \ |
257 | \ |
258 | return; \ |
259 | } \ |
260 | \ |
261 | /* --- @pre_cbcdecrypt@ --- * \ |
262 | * \ |
263 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ |
264 | * @const void *src@ = pointer to source data \ |
265 | * @void *dest@ = pointer to destination data \ |
266 | * @size_t sz@ = size of block to be encrypted \ |
267 | * \ |
268 | * Returns: --- \ |
269 | * \ |
270 | * Use: Decrypts a block with a block cipher in CBC mode, with \ |
271 | * ciphertext stealing and other clever tricks. \ |
272 | * Essentially, data can be encrypted in arbitrary sized \ |
273 | * chunks, although decryption must use the same chunks. \ |
274 | */ \ |
275 | \ |
276 | void pre##_cbcdecrypt(pre##_cbcctx *ctx, \ |
277 | const void *src, void *dest, \ |
278 | size_t sz) \ |
279 | { \ |
280 | const octet *s = src; \ |
281 | octet *d = dest; \ |
282 | \ |
283 | /* --- Empty blocks are trivial --- */ \ |
284 | \ |
285 | if (!sz) \ |
286 | return; \ |
287 | \ |
288 | /* --- Extra magical case for a short block --- * \ |
289 | * \ |
290 | * Encrypt the IV, then exclusive-or the ciphertext with the octets \ |
291 | * of the encrypted IV, shifting ciphertext octets in instead. This \ |
292 | * basically switches over to CFB. \ |
293 | */ \ |
294 | \ |
295 | if (sz < PRE##_BLKSZ) { \ |
296 | octet b[PRE##_BLKSZ], c[PRE##_BLKSZ]; \ |
297 | unsigned i; \ |
298 | \ |
299 | pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \ |
300 | BLKC_STORE(PRE, b, ctx->iv); \ |
301 | for (i = 0; i < sz; i++) { \ |
302 | register octet x = s[i]; \ |
303 | d[i] = b[i] ^ x; \ |
304 | c[i] = x; \ |
305 | } \ |
306 | memmove(b, b + sz, PRE##_BLKSZ - sz); \ |
307 | memcpy(b + PRE##_BLKSZ - sz, c, sz); \ |
308 | BLKC_LOAD(PRE, ctx->iv, b); \ |
309 | return; \ |
310 | } \ |
311 | \ |
312 | /* --- Do the main chunk of decryption --- * \ |
313 | * \ |
314 | * This will do the whole lot if it's a whole number of blocks. For \ |
315 | * each block, decrypt, XOR it with the previous ciphertext in @iv@, \ |
316 | * and keep a copy of the ciphertext for the next block. \ |
317 | */ \ |
318 | \ |
319 | while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) { \ |
320 | uint32 b[PRE##_BLKSZ / 4], niv[PRE##_BLKSZ / 4]; \ |
321 | BLKC_LOAD(PRE, niv, s); \ |
322 | pre##_dblk(&ctx->ctx, niv, b); \ |
323 | BLKC_XSTORE(PRE, d, b, ctx->iv); \ |
324 | BLKC_MOVE(PRE, ctx->iv, niv); \ |
325 | s += PRE##_BLKSZ; \ |
326 | d += PRE##_BLKSZ; \ |
327 | sz -= PRE##_BLKSZ; \ |
328 | } \ |
329 | \ |
330 | /* --- Do the tail-end block and bit-left-over --- * \ |
331 | * \ |
332 | * This isn't very efficient. That shouldn't matter much. \ |
333 | */ \ |
334 | \ |
335 | if (sz) { \ |
336 | octet b[PRE##_BLKSZ]; \ |
337 | uint32 bk[PRE##_BLKSZ / 4], niv[PRE##_BLKSZ / 4]; \ |
338 | unsigned i; \ |
339 | \ |
340 | /* --- Let @sz@ be the size of the partial block --- */ \ |
341 | \ |
342 | sz -= PRE##_BLKSZ; \ |
343 | \ |
344 | /* --- First stage --- * \ |
345 | * \ |
346 | * Take the complete ciphertext block, and decrypt it. This block \ |
347 | * is carried over for the next encryption operation. \ |
348 | */ \ |
349 | \ |
350 | BLKC_LOAD(PRE, niv, s); \ |
351 | pre##_dblk(&ctx->ctx, niv, bk); \ |
352 | \ |
353 | /* --- Second stage --- * \ |
354 | * \ |
355 | * XORing the first few bytes of this with the partial ciphertext \ |
356 | * block recovers the partial plaintext block. At the same time, \ |
357 | * write the partial ciphertext block's contents in ready for stage \ |
358 | * three. \ |
359 | */ \ |
360 | \ |
361 | BLKC_STORE(PRE, b, bk); \ |
362 | s += PRE##_BLKSZ; \ |
363 | d += PRE##_BLKSZ; \ |
364 | for (i = 0; i < sz; i++) { \ |
365 | register octet x = s[i]; \ |
366 | d[i] = b[i] ^ x; \ |
367 | b[i] = x; \ |
368 | } \ |
369 | \ |
370 | /* --- Third stage --- * \ |
371 | * \ |
372 | * Decrypt the block we've got left, and XOR with the initial IV to \ |
373 | * recover the complete plaintext block. \ |
374 | */ \ |
375 | \ |
376 | BLKC_LOAD(PRE, bk, b); \ |
377 | pre##_dblk(&ctx->ctx, bk, bk); \ |
378 | BLKC_XSTORE(PRE, d - PRE##_BLKSZ, bk, ctx->iv); \ |
379 | BLKC_MOVE(PRE, ctx->iv, niv); \ |
380 | } \ |
381 | \ |
382 | /* --- Done --- */ \ |
383 | \ |
384 | return; \ |
385 | } \ |
386 | \ |
387 | /* --- Generic cipher interface --- */ \ |
388 | \ |
389 | static const gcipher_ops gops; \ |
390 | \ |
391 | typedef struct gctx { \ |
392 | gcipher c; \ |
393 | pre##_cbcctx k; \ |
394 | } gctx; \ |
395 | \ |
396 | static gcipher *ginit(const void *k, size_t sz) \ |
397 | { \ |
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398 | gctx *g = S_CREATE(gctx); \ |
79ba130c |
399 | g->c.ops = &gops; \ |
400 | pre##_cbcinit(&g->k, k, sz, 0); \ |
401 | return (&g->c); \ |
402 | } \ |
403 | \ |
404 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
405 | { \ |
406 | gctx *g = (gctx *)c; \ |
407 | pre##_cbcencrypt(&g->k, s, t, sz); \ |
408 | } \ |
409 | \ |
410 | static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
411 | { \ |
412 | gctx *g = (gctx *)c; \ |
413 | pre##_cbcdecrypt(&g->k, s, t, sz); \ |
414 | } \ |
415 | \ |
416 | static void gdestroy(gcipher *c) \ |
417 | { \ |
418 | gctx *g = (gctx *)c; \ |
99461409 |
419 | BURN(*g); \ |
420 | S_DESTROY(g); \ |
79ba130c |
421 | } \ |
422 | \ |
423 | static void gsetiv(gcipher *c, const void *iv) \ |
424 | { \ |
425 | gctx *g = (gctx *)c; \ |
426 | pre##_cbcsetiv(&g->k, iv); \ |
427 | } \ |
428 | \ |
429 | static const gcipher_ops gops = { \ |
99461409 |
430 | &pre##_cbc, \ |
431 | gencrypt, gdecrypt, gdestroy, gsetiv, 0 \ |
79ba130c |
432 | }; \ |
433 | \ |
434 | const gccipher pre##_cbc = { \ |
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435 | #pre "-cbc", pre##_keysz, PRE##_BLKSZ, \ |
79ba130c |
436 | ginit \ |
437 | }; \ |
438 | \ |
439 | CBC_TEST(PRE, pre) |
440 | |
441 | /*----- Test rig ----------------------------------------------------------*/ |
442 | |
443 | #ifdef TEST_RIG |
444 | |
445 | #include <stdio.h> |
446 | |
447 | #include "daftstory.h" |
448 | |
449 | /* --- @CBC_TEST@ --- * |
450 | * |
451 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
452 | * |
453 | * Use: Standard test rig for CBC functions. |
454 | */ |
455 | |
456 | #define CBC_TEST(PRE, pre) \ |
457 | \ |
458 | /* --- Initial plaintext for the test --- */ \ |
459 | \ |
460 | static const octet text[] = TEXT; \ |
461 | \ |
462 | /* --- Key and IV to use --- */ \ |
463 | \ |
464 | static const octet key[] = KEY; \ |
465 | static const octet iv[] = IV; \ |
466 | \ |
467 | /* --- Buffers for encryption and decryption output --- */ \ |
468 | \ |
469 | static octet ct[sizeof(text)]; \ |
470 | static octet pt[sizeof(text)]; \ |
471 | \ |
472 | static void hexdump(const octet *p, size_t sz) \ |
473 | { \ |
474 | const octet *q = p + sz; \ |
475 | for (sz = 0; p < q; p++, sz++) { \ |
476 | printf("%02x", *p); \ |
477 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
478 | putchar(':'); \ |
479 | } \ |
480 | } \ |
481 | \ |
482 | int main(void) \ |
483 | { \ |
484 | size_t sz = 0, rest; \ |
485 | pre##_cbcctx ctx; \ |
486 | pre##_ctx k; \ |
487 | int status = 0; \ |
488 | int done = 0; \ |
489 | \ |
490 | size_t keysz = PRE##_KEYSZ ? \ |
491 | PRE##_KEYSZ : strlen((const char *)key); \ |
492 | \ |
493 | fputs(#pre "-cbc: ", stdout); \ |
494 | \ |
495 | pre##_init(&k, key, keysz); \ |
496 | pre##_cbcsetkey(&ctx, &k); \ |
497 | \ |
498 | while (sz <= sizeof(text)) { \ |
499 | rest = sizeof(text) - sz; \ |
500 | memcpy(ct, text, sizeof(text)); \ |
501 | pre##_cbcsetiv(&ctx, iv); \ |
502 | pre##_cbcencrypt(&ctx, ct, ct, sz); \ |
503 | pre##_cbcencrypt(&ctx, ct + sz, ct + sz, rest); \ |
504 | memcpy(pt, ct, sizeof(text)); \ |
505 | pre##_cbcsetiv(&ctx, iv); \ |
506 | pre##_cbcdecrypt(&ctx, pt, pt, sz); \ |
507 | pre##_cbcdecrypt(&ctx, pt + sz, pt + sz, rest); \ |
508 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
509 | done++; \ |
510 | if (sizeof(text) < 40 || done % 8 == 0) \ |
511 | fputc('.', stdout); \ |
512 | if (done % 480 == 0) \ |
513 | fputs("\n\t", stdout); \ |
514 | fflush(stdout); \ |
515 | } else { \ |
516 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
517 | status = 1; \ |
518 | printf("\tplaintext = "); hexdump(text, sz); \ |
519 | printf(", "); hexdump(text + sz, rest); \ |
520 | fputc('\n', stdout); \ |
521 | printf("\tciphertext = "); hexdump(ct, sz); \ |
522 | printf(", "); hexdump(ct + sz, rest); \ |
523 | fputc('\n', stdout); \ |
524 | printf("\trecovered text = "); hexdump(pt, sz); \ |
525 | printf(", "); hexdump(pt + sz, rest); \ |
526 | fputc('\n', stdout); \ |
527 | fputc('\n', stdout); \ |
528 | } \ |
529 | if (sz < 63) \ |
530 | sz++; \ |
531 | else \ |
532 | sz += 9; \ |
533 | } \ |
534 | \ |
535 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
536 | return (status); \ |
537 | } |
538 | |
539 | #else |
540 | # define CBC_TEST(PRE, pre) |
541 | #endif |
542 | |
543 | /*----- That's all, folks -------------------------------------------------*/ |
544 | |
545 | #ifdef __cplusplus |
546 | } |
547 | #endif |
548 | |
549 | #endif |