79ba130c |
1 | /* -*-c-*- |
2 | * |
4efe32ba |
3 | * $Id: ofb-def.h,v 1.5 2001/06/17 00:10:51 mdw Exp $ |
79ba130c |
4 | * |
5 | * Definitions for output 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: ofb-def.h,v $ |
4efe32ba |
33 | * Revision 1.5 2001/06/17 00:10:51 mdw |
34 | * Typesetting fixes |
35 | * |
360c232e |
36 | * Revision 1.4 2001/04/03 19:36:36 mdw |
37 | * Don't use @va_arg@ as an argument to @STORE32@! |
38 | * |
2af20fa2 |
39 | * Revision 1.3 2000/06/17 11:48:02 mdw |
40 | * Use secure arena for memory allocation. Rearrange setiv slightly. |
41 | * |
4ab1268f |
42 | * Revision 1.2 1999/12/13 15:34:01 mdw |
43 | * Add support for seeding from a generic pseudorandom source. |
44 | * |
79ba130c |
45 | * Revision 1.1 1999/12/10 23:16:40 mdw |
46 | * Split mode macros into interface and implementation. |
47 | * |
48 | */ |
49 | |
50 | #ifndef CATACOMB_OFB_DEF_H |
51 | #define CATACOMB_OFB_DEF_H |
52 | |
53 | #ifdef __cplusplus |
54 | extern "C" { |
55 | #endif |
56 | |
57 | /*----- Header files ------------------------------------------------------*/ |
58 | |
59 | #include <stdarg.h> |
60 | #include <string.h> |
61 | |
62 | #include <mLib/bits.h> |
63 | #include <mLib/sub.h> |
64 | |
2af20fa2 |
65 | #ifndef CATACOMB_ARENA_H |
66 | # include "arena.h" |
67 | #endif |
68 | |
79ba130c |
69 | #ifndef CATACOMB_BLKC_H |
70 | # include "blkc.h" |
71 | #endif |
72 | |
73 | #ifndef CATACOMB_GCIPHER_H |
74 | # include "gcipher.h" |
75 | #endif |
76 | |
77 | #ifndef CATACOMB_PARANOIA_H |
78 | # include "paranoia.h" |
79 | #endif |
80 | |
81 | /*----- Macros ------------------------------------------------------------*/ |
82 | |
83 | /* --- @OFB_DEF@ --- * |
84 | * |
85 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
86 | * |
87 | * Use: Creates definitions for output feedback mode. |
88 | */ |
89 | |
90 | #define OFB_DEF(PRE, pre) \ |
91 | \ |
92 | /* --- @pre_ofbgetiv@ --- * \ |
93 | * \ |
94 | * Arguments: @const pre_ofbctx *ctx@ = pointer to OFB context block \ |
4efe32ba |
95 | * @void *iv@ = pointer to output data block \ |
79ba130c |
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##_ofbgetiv(const pre##_ofbctx *ctx, void *iv) \ |
106 | { \ |
107 | octet *p = iv; \ |
2af20fa2 |
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_ofbsetiv@ --- * \ |
115 | * \ |
116 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB 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##_ofbsetiv(pre##_ofbctx *ctx, const void *iv) \ |
125 | { \ |
2af20fa2 |
126 | memcpy(ctx->iv, iv, PRE##_BLKSZ); \ |
127 | ctx->off = PRE##_BLKSZ; \ |
79ba130c |
128 | } \ |
129 | \ |
130 | /* --- @pre_ofbbdry@ --- * \ |
131 | * \ |
132 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB 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##_ofbbdry(pre##_ofbctx *ctx) \ |
141 | { \ |
2af20fa2 |
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); \ |
79ba130c |
148 | } \ |
149 | \ |
150 | /* --- @pre_ofbsetkey@ --- * \ |
151 | * \ |
152 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
153 | * @const pre_ctx *k@ = pointer to cipher context \ |
154 | * \ |
155 | * Returns: --- \ |
156 | * \ |
157 | * Use: Sets the OFB context to use a different cipher key. \ |
158 | */ \ |
159 | \ |
160 | void pre##_ofbsetkey(pre##_ofbctx *ctx, const pre##_ctx *k) \ |
161 | { \ |
162 | ctx->ctx = *k; \ |
163 | } \ |
164 | \ |
165 | /* --- @pre_ofbinit@ --- * \ |
166 | * \ |
167 | * Arguments: @pre_ofbctx *ctx@ = pointer to cipher context \ |
168 | * @const void *key@ = pointer to the key buffer \ |
169 | * @size_t sz@ = size of the key \ |
170 | * @const void *iv@ = pointer to initialization vector \ |
171 | * \ |
172 | * Returns: --- \ |
173 | * \ |
174 | * Use: Initializes a OFB context ready for use. You should \ |
175 | * ensure that the IV chosen is unique: reusing an IV will \ |
176 | * compromise the security of the entire plaintext. This \ |
177 | * is equivalent to calls to @pre_init@, @pre_ofbsetkey@ \ |
178 | * and @pre_ofbsetiv@. \ |
179 | */ \ |
180 | \ |
181 | void pre##_ofbinit(pre##_ofbctx *ctx, \ |
182 | const void *key, size_t sz, \ |
183 | const void *iv) \ |
184 | { \ |
185 | static octet zero[PRE##_BLKSZ] = { 0 }; \ |
186 | pre##_init(&ctx->ctx, key, sz); \ |
187 | pre##_ofbsetiv(ctx, iv ? iv : zero); \ |
188 | } \ |
189 | \ |
190 | /* --- @pre_ofbencrypt@ --- * \ |
191 | * \ |
192 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
193 | * @const void *src@ = pointer to source data \ |
194 | * @void *dest@ = pointer to destination data \ |
195 | * @size_t sz@ = size of block to be encrypted \ |
196 | * \ |
197 | * Returns: --- \ |
198 | * \ |
199 | * Use: Encrypts or decrypts a block with a block cipher in OFB \ |
200 | * mode: encryption and decryption are the same in OFB. \ |
201 | * The destination may be null to just churn the feedback \ |
202 | * round for a bit. The source may be null to use the \ |
203 | * cipher as a random data generator. \ |
204 | */ \ |
205 | \ |
206 | void pre##_ofbencrypt(pre##_ofbctx *ctx, \ |
207 | const void *src, void *dest, \ |
208 | size_t sz) \ |
209 | { \ |
210 | const octet *s = src; \ |
211 | octet *d = dest; \ |
2af20fa2 |
212 | unsigned off = ctx->off; \ |
79ba130c |
213 | \ |
214 | /* --- Empty blocks are trivial --- */ \ |
215 | \ |
216 | if (!sz) \ |
217 | return; \ |
218 | \ |
219 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
220 | \ |
221 | if (sz < PRE##_BLKSZ - off) \ |
222 | goto small; \ |
223 | \ |
224 | /* --- Finish off what's left in my buffer --- */ \ |
225 | \ |
226 | if (!d) \ |
2af20fa2 |
227 | sz -= PRE##_BLKSZ - off; \ |
79ba130c |
228 | else { \ |
229 | while (off < PRE##_BLKSZ) { \ |
230 | register octet x = s ? *s++ : 0; \ |
231 | *d++ = ctx->iv[off++] ^ x; \ |
232 | sz--; \ |
233 | } \ |
234 | } \ |
235 | \ |
236 | /* --- Main encryption loop --- */ \ |
237 | \ |
238 | { \ |
239 | uint32 iv[PRE##_BLKSZ / 4]; \ |
240 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
241 | \ |
242 | for (;;) { \ |
243 | pre##_eblk(&ctx->ctx, iv, iv); \ |
244 | if (sz < PRE##_BLKSZ) \ |
245 | break; \ |
246 | if (d) { \ |
247 | if (!s) \ |
248 | BLKC_STORE(PRE, d, iv); \ |
249 | else { \ |
250 | uint32 x[PRE##_BLKSZ / 4]; \ |
251 | BLKC_LOAD(PRE, x, s); \ |
252 | BLKC_XSTORE(PRE, d, iv, x); \ |
253 | s += PRE##_BLKSZ; \ |
254 | } \ |
255 | d += PRE##_BLKSZ; \ |
256 | } \ |
257 | sz -= PRE##_BLKSZ; \ |
258 | } \ |
259 | \ |
260 | BLKC_STORE(PRE, ctx->iv, iv); \ |
261 | off = 0; \ |
262 | } \ |
263 | \ |
264 | /* --- Tidying up the tail end --- */ \ |
265 | \ |
266 | if (sz) { \ |
267 | small: \ |
268 | if (!d) \ |
269 | off += sz; \ |
270 | else do { \ |
271 | register octet x = s ? *s++ : 0; \ |
272 | *d++ = ctx->iv[off++] ^ x; \ |
273 | sz--; \ |
274 | } while (sz); \ |
275 | } \ |
276 | \ |
277 | /* --- Done --- */ \ |
278 | \ |
279 | ctx->off = off; \ |
280 | return; \ |
281 | } \ |
282 | \ |
283 | /* --- Generic cipher interface --- */ \ |
284 | \ |
285 | static const gcipher_ops gops; \ |
286 | \ |
287 | typedef struct gctx { \ |
288 | gcipher c; \ |
289 | pre##_ofbctx k; \ |
290 | } gctx; \ |
291 | \ |
292 | static gcipher *ginit(const void *k, size_t sz) \ |
293 | { \ |
2af20fa2 |
294 | gctx *g = S_CREATE(gctx); \ |
79ba130c |
295 | g->c.ops = &gops; \ |
296 | pre##_ofbinit(&g->k, k, sz, 0); \ |
297 | return (&g->c); \ |
298 | } \ |
299 | \ |
300 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
301 | { \ |
302 | gctx *g = (gctx *)c; \ |
303 | pre##_ofbencrypt(&g->k, s, t, sz); \ |
304 | } \ |
305 | \ |
306 | static void gdestroy(gcipher *c) \ |
307 | { \ |
308 | gctx *g = (gctx *)c; \ |
2af20fa2 |
309 | BURN(*g); \ |
310 | S_DESTROY(g); \ |
79ba130c |
311 | } \ |
312 | \ |
313 | static void gsetiv(gcipher *c, const void *iv) \ |
314 | { \ |
315 | gctx *g = (gctx *)c; \ |
316 | pre##_ofbsetiv(&g->k, iv); \ |
317 | } \ |
318 | \ |
319 | static void gbdry(gcipher *c) \ |
320 | { \ |
321 | gctx *g = (gctx *)c; \ |
322 | pre##_ofbbdry(&g->k); \ |
323 | } \ |
324 | \ |
325 | static const gcipher_ops gops = { \ |
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326 | &pre##_ofb, \ |
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327 | gencrypt, gencrypt, gdestroy, gsetiv, gbdry \ |
328 | }; \ |
329 | \ |
330 | const gccipher pre##_ofb = { \ |
2af20fa2 |
331 | #pre "-ofb", pre##_keysz, PRE##_BLKSZ, \ |
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332 | ginit \ |
333 | }; \ |
334 | \ |
335 | /* --- Generic random number generator interface --- */ \ |
336 | \ |
337 | typedef struct grctx { \ |
338 | grand r; \ |
339 | pre##_ofbctx k; \ |
340 | } grctx; \ |
341 | \ |
342 | static void grdestroy(grand *r) \ |
343 | { \ |
344 | grctx *g = (grctx *)r; \ |
2af20fa2 |
345 | BURN(*g); \ |
346 | S_DESTROY(g); \ |
79ba130c |
347 | } \ |
348 | \ |
349 | static int grmisc(grand *r, unsigned op, ...) \ |
350 | { \ |
351 | grctx *g = (grctx *)r; \ |
352 | va_list ap; \ |
353 | int rc = 0; \ |
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354 | uint32 i; \ |
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355 | octet buf[PRE##_BLKSZ]; \ |
356 | va_start(ap, op); \ |
357 | \ |
358 | switch (op) { \ |
359 | case GRAND_CHECK: \ |
360 | switch (va_arg(ap, unsigned)) { \ |
361 | case GRAND_CHECK: \ |
362 | case GRAND_SEEDINT: \ |
363 | case GRAND_SEEDUINT32: \ |
364 | case GRAND_SEEDBLOCK: \ |
4ab1268f |
365 | case GRAND_SEEDRAND: \ |
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366 | rc = 1; \ |
367 | break; \ |
368 | default: \ |
369 | rc = 0; \ |
370 | break; \ |
371 | } \ |
372 | break; \ |
373 | case GRAND_SEEDINT: \ |
374 | memset(buf, 0, sizeof(buf)); \ |
360c232e |
375 | i = va_arg(ap, unsigned); \ |
376 | STORE32(buf, i); \ |
79ba130c |
377 | pre##_ofbsetiv(&g->k, buf); \ |
378 | break; \ |
379 | case GRAND_SEEDUINT32: \ |
380 | memset(buf, 0, sizeof(buf)); \ |
360c232e |
381 | i = va_arg(ap, uint32); \ |
382 | STORE32(buf, i); \ |
79ba130c |
383 | pre##_ofbsetiv(&g->k, buf); \ |
384 | break; \ |
385 | case GRAND_SEEDBLOCK: { \ |
386 | const void *p = va_arg(ap, const void *); \ |
387 | size_t sz = va_arg(ap, size_t); \ |
388 | if (sz < sizeof(buf)) { \ |
389 | memset(buf, 0, sizeof(buf)); \ |
390 | memcpy(buf, p, sz); \ |
391 | p = buf; \ |
392 | } \ |
393 | pre##_ofbsetiv(&g->k, p); \ |
394 | } break; \ |
4ab1268f |
395 | case GRAND_SEEDRAND: { \ |
396 | grand *rr = va_arg(ap, grand *); \ |
397 | rr->ops->fill(rr, buf, sizeof(buf)); \ |
398 | pre##_ofbsetiv(&g->k, buf); \ |
399 | } break; \ |
400 | default: \ |
401 | GRAND_BADOP; \ |
402 | break; \ |
79ba130c |
403 | } \ |
404 | \ |
405 | va_end(ap); \ |
406 | return (rc); \ |
407 | } \ |
408 | \ |
409 | static octet grbyte(grand *r) \ |
410 | { \ |
411 | grctx *g = (grctx *)r; \ |
412 | octet o; \ |
413 | pre##_ofbencrypt(&g->k, 0, &o, 1); \ |
414 | return (o); \ |
415 | } \ |
416 | \ |
417 | static uint32 grword(grand *r) \ |
418 | { \ |
419 | grctx *g = (grctx *)r; \ |
420 | octet b[4]; \ |
421 | pre##_ofbencrypt(&g->k, 0, b, sizeof(b)); \ |
422 | return (LOAD32(b)); \ |
423 | } \ |
424 | \ |
425 | static void grfill(grand *r, void *p, size_t sz) \ |
426 | { \ |
427 | grctx *g = (grctx *)r; \ |
428 | pre##_ofbencrypt(&g->k, 0, p, sz); \ |
429 | } \ |
430 | \ |
431 | static const grand_ops grops = { \ |
432 | #pre "-ofb", \ |
2af20fa2 |
433 | GRAND_CRYPTO, 0, \ |
79ba130c |
434 | grmisc, grdestroy, \ |
435 | grword, grbyte, grword, grand_range, grfill \ |
436 | }; \ |
437 | \ |
438 | /* --- @pre_ofbrand@ --- * \ |
439 | * \ |
440 | * Arguments: @const void *k@ = pointer to key material \ |
441 | * @size_t sz@ = size of key material \ |
442 | * \ |
443 | * Returns: Pointer to generic random number generator interface. \ |
444 | * \ |
445 | * Use: Creates a random number interface wrapper around an \ |
446 | * OFB-mode block cipher. \ |
447 | */ \ |
448 | \ |
449 | grand *pre##_ofbrand(const void *k, size_t sz) \ |
450 | { \ |
2af20fa2 |
451 | grctx *g = S_CREATE(grctx); \ |
79ba130c |
452 | g->r.ops = &grops; \ |
453 | pre##_ofbinit(&g->k, k, sz, 0); \ |
454 | return (&g->r); \ |
455 | } \ |
456 | \ |
457 | OFB_TEST(PRE, pre) |
458 | |
459 | /*----- Test rig ----------------------------------------------------------*/ |
460 | |
461 | #ifdef TEST_RIG |
462 | |
463 | #include <stdio.h> |
464 | |
465 | #include "daftstory.h" |
466 | |
467 | /* --- @OFB_TEST@ --- * |
468 | * |
469 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
470 | * |
471 | * Use: Standard test rig for OFB functions. |
472 | */ |
473 | |
474 | #define OFB_TEST(PRE, pre) \ |
475 | \ |
476 | /* --- Initial plaintext for the test --- */ \ |
477 | \ |
478 | static const octet text[] = TEXT; \ |
479 | \ |
480 | /* --- Key and IV to use --- */ \ |
481 | \ |
482 | static const octet key[] = KEY; \ |
483 | static const octet iv[] = IV; \ |
484 | \ |
485 | /* --- Buffers for encryption and decryption output --- */ \ |
486 | \ |
487 | static octet ct[sizeof(text)]; \ |
488 | static octet pt[sizeof(text)]; \ |
489 | \ |
490 | static void hexdump(const octet *p, size_t sz) \ |
491 | { \ |
492 | const octet *q = p + sz; \ |
493 | for (sz = 0; p < q; p++, sz++) { \ |
494 | printf("%02x", *p); \ |
495 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
496 | putchar(':'); \ |
497 | } \ |
498 | } \ |
499 | \ |
500 | int main(void) \ |
501 | { \ |
502 | size_t sz = 0, rest; \ |
503 | pre##_ofbctx ctx; \ |
504 | int status = 0; \ |
505 | int done = 0; \ |
506 | pre##_ctx k; \ |
507 | \ |
508 | size_t keysz = PRE##_KEYSZ ? \ |
509 | PRE##_KEYSZ : strlen((const char *)key); \ |
510 | \ |
511 | fputs(#pre "-ofb: ", stdout); \ |
512 | \ |
513 | pre##_init(&k, key, keysz); \ |
514 | pre##_ofbsetkey(&ctx, &k); \ |
515 | \ |
516 | while (sz <= sizeof(text)) { \ |
517 | rest = sizeof(text) - sz; \ |
518 | memcpy(ct, text, sizeof(text)); \ |
519 | pre##_ofbsetiv(&ctx, iv); \ |
520 | pre##_ofbencrypt(&ctx, ct, ct, sz); \ |
521 | pre##_ofbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
522 | memcpy(pt, ct, sizeof(text)); \ |
523 | pre##_ofbsetiv(&ctx, iv); \ |
524 | pre##_ofbencrypt(&ctx, pt, pt, rest); \ |
525 | pre##_ofbencrypt(&ctx, pt + rest, pt + rest, sz); \ |
526 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
527 | done++; \ |
528 | if (sizeof(text) < 40 || done % 8 == 0) \ |
529 | fputc('.', stdout); \ |
530 | if (done % 480 == 0) \ |
531 | fputs("\n\t", stdout); \ |
532 | fflush(stdout); \ |
533 | } else { \ |
534 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
535 | status = 1; \ |
536 | printf("\tplaintext = "); hexdump(text, sz); \ |
537 | printf(", "); hexdump(text + sz, rest); \ |
538 | fputc('\n', stdout); \ |
539 | printf("\tciphertext = "); hexdump(ct, sz); \ |
540 | printf(", "); hexdump(ct + sz, rest); \ |
541 | fputc('\n', stdout); \ |
542 | printf("\trecovered text = "); hexdump(pt, sz); \ |
543 | printf(", "); hexdump(pt + sz, rest); \ |
544 | fputc('\n', stdout); \ |
545 | fputc('\n', stdout); \ |
546 | } \ |
547 | if (sz < 63) \ |
548 | sz++; \ |
549 | else \ |
550 | sz += 9; \ |
551 | } \ |
552 | \ |
553 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
554 | return (status); \ |
555 | } |
556 | |
557 | #else |
558 | # define OFB_TEST(PRE, pre) |
559 | #endif |
560 | |
561 | /*----- That's all, folks -------------------------------------------------*/ |
562 | |
563 | #ifdef __cplusplus |
564 | } |
565 | #endif |
566 | |
567 | #endif |