79ba130c |
1 | /* -*-c-*- |
2 | * |
2af20fa2 |
3 | * $Id: ofb-def.h,v 1.3 2000/06/17 11:48:02 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 $ |
2af20fa2 |
33 | * Revision 1.3 2000/06/17 11:48:02 mdw |
34 | * Use secure arena for memory allocation. Rearrange setiv slightly. |
35 | * |
4ab1268f |
36 | * Revision 1.2 1999/12/13 15:34:01 mdw |
37 | * Add support for seeding from a generic pseudorandom source. |
38 | * |
79ba130c |
39 | * Revision 1.1 1999/12/10 23:16:40 mdw |
40 | * Split mode macros into interface and implementation. |
41 | * |
42 | */ |
43 | |
44 | #ifndef CATACOMB_OFB_DEF_H |
45 | #define CATACOMB_OFB_DEF_H |
46 | |
47 | #ifdef __cplusplus |
48 | extern "C" { |
49 | #endif |
50 | |
51 | /*----- Header files ------------------------------------------------------*/ |
52 | |
53 | #include <stdarg.h> |
54 | #include <string.h> |
55 | |
56 | #include <mLib/bits.h> |
57 | #include <mLib/sub.h> |
58 | |
2af20fa2 |
59 | #ifndef CATACOMB_ARENA_H |
60 | # include "arena.h" |
61 | #endif |
62 | |
79ba130c |
63 | #ifndef CATACOMB_BLKC_H |
64 | # include "blkc.h" |
65 | #endif |
66 | |
67 | #ifndef CATACOMB_GCIPHER_H |
68 | # include "gcipher.h" |
69 | #endif |
70 | |
71 | #ifndef CATACOMB_PARANOIA_H |
72 | # include "paranoia.h" |
73 | #endif |
74 | |
75 | /*----- Macros ------------------------------------------------------------*/ |
76 | |
77 | /* --- @OFB_DEF@ --- * |
78 | * |
79 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
80 | * |
81 | * Use: Creates definitions for output feedback mode. |
82 | */ |
83 | |
84 | #define OFB_DEF(PRE, pre) \ |
85 | \ |
86 | /* --- @pre_ofbgetiv@ --- * \ |
87 | * \ |
88 | * Arguments: @const pre_ofbctx *ctx@ = pointer to OFB context block \ |
89 | * @void *iv#@ = pointer to output data block \ |
90 | * \ |
91 | * Returns: --- \ |
92 | * \ |
93 | * Use: Reads the currently set IV. Reading and setting an IV \ |
94 | * is not transparent to the cipher. It will add a `step' \ |
95 | * which must be matched by a similar operation during \ |
96 | * decryption. \ |
97 | */ \ |
98 | \ |
99 | void pre##_ofbgetiv(const pre##_ofbctx *ctx, void *iv) \ |
100 | { \ |
101 | octet *p = iv; \ |
2af20fa2 |
102 | unsigned off = ctx->off; \ |
103 | unsigned rest = PRE##_BLKSZ - off; \ |
79ba130c |
104 | memcpy(p, ctx->iv + off, rest); \ |
105 | memcpy(p + rest, ctx->iv, off); \ |
106 | } \ |
107 | \ |
108 | /* --- @pre_ofbsetiv@ --- * \ |
109 | * \ |
110 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
111 | * @cnost void *iv@ = pointer to IV to set \ |
112 | * \ |
113 | * Returns: --- \ |
114 | * \ |
115 | * Use: Sets the IV to use for subsequent encryption. \ |
116 | */ \ |
117 | \ |
118 | void pre##_ofbsetiv(pre##_ofbctx *ctx, const void *iv) \ |
119 | { \ |
2af20fa2 |
120 | memcpy(ctx->iv, iv, PRE##_BLKSZ); \ |
121 | ctx->off = PRE##_BLKSZ; \ |
79ba130c |
122 | } \ |
123 | \ |
124 | /* --- @pre_ofbbdry@ --- * \ |
125 | * \ |
126 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
127 | * \ |
128 | * Returns: --- \ |
129 | * \ |
130 | * Use: Inserts a boundary during encryption. Successful \ |
131 | * decryption must place a similar boundary. \ |
132 | */ \ |
133 | \ |
134 | void pre##_ofbbdry(pre##_ofbctx *ctx) \ |
135 | { \ |
2af20fa2 |
136 | uint32 niv[PRE##_BLKSZ / 4]; \ |
137 | BLKC_LOAD(PRE, niv, ctx->iv); \ |
138 | pre##_eblk(&ctx->ctx, niv, niv); \ |
139 | BLKC_STORE(PRE, ctx->iv, niv); \ |
140 | ctx->off = PRE##_BLKSZ; \ |
141 | BURN(niv); \ |
79ba130c |
142 | } \ |
143 | \ |
144 | /* --- @pre_ofbsetkey@ --- * \ |
145 | * \ |
146 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
147 | * @const pre_ctx *k@ = pointer to cipher context \ |
148 | * \ |
149 | * Returns: --- \ |
150 | * \ |
151 | * Use: Sets the OFB context to use a different cipher key. \ |
152 | */ \ |
153 | \ |
154 | void pre##_ofbsetkey(pre##_ofbctx *ctx, const pre##_ctx *k) \ |
155 | { \ |
156 | ctx->ctx = *k; \ |
157 | } \ |
158 | \ |
159 | /* --- @pre_ofbinit@ --- * \ |
160 | * \ |
161 | * Arguments: @pre_ofbctx *ctx@ = pointer to cipher context \ |
162 | * @const void *key@ = pointer to the key buffer \ |
163 | * @size_t sz@ = size of the key \ |
164 | * @const void *iv@ = pointer to initialization vector \ |
165 | * \ |
166 | * Returns: --- \ |
167 | * \ |
168 | * Use: Initializes a OFB context ready for use. You should \ |
169 | * ensure that the IV chosen is unique: reusing an IV will \ |
170 | * compromise the security of the entire plaintext. This \ |
171 | * is equivalent to calls to @pre_init@, @pre_ofbsetkey@ \ |
172 | * and @pre_ofbsetiv@. \ |
173 | */ \ |
174 | \ |
175 | void pre##_ofbinit(pre##_ofbctx *ctx, \ |
176 | const void *key, size_t sz, \ |
177 | const void *iv) \ |
178 | { \ |
179 | static octet zero[PRE##_BLKSZ] = { 0 }; \ |
180 | pre##_init(&ctx->ctx, key, sz); \ |
181 | pre##_ofbsetiv(ctx, iv ? iv : zero); \ |
182 | } \ |
183 | \ |
184 | /* --- @pre_ofbencrypt@ --- * \ |
185 | * \ |
186 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
187 | * @const void *src@ = pointer to source data \ |
188 | * @void *dest@ = pointer to destination data \ |
189 | * @size_t sz@ = size of block to be encrypted \ |
190 | * \ |
191 | * Returns: --- \ |
192 | * \ |
193 | * Use: Encrypts or decrypts a block with a block cipher in OFB \ |
194 | * mode: encryption and decryption are the same in OFB. \ |
195 | * The destination may be null to just churn the feedback \ |
196 | * round for a bit. The source may be null to use the \ |
197 | * cipher as a random data generator. \ |
198 | */ \ |
199 | \ |
200 | void pre##_ofbencrypt(pre##_ofbctx *ctx, \ |
201 | const void *src, void *dest, \ |
202 | size_t sz) \ |
203 | { \ |
204 | const octet *s = src; \ |
205 | octet *d = dest; \ |
2af20fa2 |
206 | unsigned off = ctx->off; \ |
79ba130c |
207 | \ |
208 | /* --- Empty blocks are trivial --- */ \ |
209 | \ |
210 | if (!sz) \ |
211 | return; \ |
212 | \ |
213 | /* --- If I can deal with the block from my buffer, do that --- */ \ |
214 | \ |
215 | if (sz < PRE##_BLKSZ - off) \ |
216 | goto small; \ |
217 | \ |
218 | /* --- Finish off what's left in my buffer --- */ \ |
219 | \ |
220 | if (!d) \ |
2af20fa2 |
221 | sz -= PRE##_BLKSZ - off; \ |
79ba130c |
222 | else { \ |
223 | while (off < PRE##_BLKSZ) { \ |
224 | register octet x = s ? *s++ : 0; \ |
225 | *d++ = ctx->iv[off++] ^ x; \ |
226 | sz--; \ |
227 | } \ |
228 | } \ |
229 | \ |
230 | /* --- Main encryption loop --- */ \ |
231 | \ |
232 | { \ |
233 | uint32 iv[PRE##_BLKSZ / 4]; \ |
234 | BLKC_LOAD(PRE, iv, ctx->iv); \ |
235 | \ |
236 | for (;;) { \ |
237 | pre##_eblk(&ctx->ctx, iv, iv); \ |
238 | if (sz < PRE##_BLKSZ) \ |
239 | break; \ |
240 | if (d) { \ |
241 | if (!s) \ |
242 | BLKC_STORE(PRE, d, iv); \ |
243 | else { \ |
244 | uint32 x[PRE##_BLKSZ / 4]; \ |
245 | BLKC_LOAD(PRE, x, s); \ |
246 | BLKC_XSTORE(PRE, d, iv, x); \ |
247 | s += PRE##_BLKSZ; \ |
248 | } \ |
249 | d += PRE##_BLKSZ; \ |
250 | } \ |
251 | sz -= PRE##_BLKSZ; \ |
252 | } \ |
253 | \ |
254 | BLKC_STORE(PRE, ctx->iv, iv); \ |
255 | off = 0; \ |
256 | } \ |
257 | \ |
258 | /* --- Tidying up the tail end --- */ \ |
259 | \ |
260 | if (sz) { \ |
261 | small: \ |
262 | if (!d) \ |
263 | off += sz; \ |
264 | else do { \ |
265 | register octet x = s ? *s++ : 0; \ |
266 | *d++ = ctx->iv[off++] ^ x; \ |
267 | sz--; \ |
268 | } while (sz); \ |
269 | } \ |
270 | \ |
271 | /* --- Done --- */ \ |
272 | \ |
273 | ctx->off = off; \ |
274 | return; \ |
275 | } \ |
276 | \ |
277 | /* --- Generic cipher interface --- */ \ |
278 | \ |
279 | static const gcipher_ops gops; \ |
280 | \ |
281 | typedef struct gctx { \ |
282 | gcipher c; \ |
283 | pre##_ofbctx k; \ |
284 | } gctx; \ |
285 | \ |
286 | static gcipher *ginit(const void *k, size_t sz) \ |
287 | { \ |
2af20fa2 |
288 | gctx *g = S_CREATE(gctx); \ |
79ba130c |
289 | g->c.ops = &gops; \ |
290 | pre##_ofbinit(&g->k, k, sz, 0); \ |
291 | return (&g->c); \ |
292 | } \ |
293 | \ |
294 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
295 | { \ |
296 | gctx *g = (gctx *)c; \ |
297 | pre##_ofbencrypt(&g->k, s, t, sz); \ |
298 | } \ |
299 | \ |
300 | static void gdestroy(gcipher *c) \ |
301 | { \ |
302 | gctx *g = (gctx *)c; \ |
2af20fa2 |
303 | BURN(*g); \ |
304 | S_DESTROY(g); \ |
79ba130c |
305 | } \ |
306 | \ |
307 | static void gsetiv(gcipher *c, const void *iv) \ |
308 | { \ |
309 | gctx *g = (gctx *)c; \ |
310 | pre##_ofbsetiv(&g->k, iv); \ |
311 | } \ |
312 | \ |
313 | static void gbdry(gcipher *c) \ |
314 | { \ |
315 | gctx *g = (gctx *)c; \ |
316 | pre##_ofbbdry(&g->k); \ |
317 | } \ |
318 | \ |
319 | static const gcipher_ops gops = { \ |
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320 | &pre##_ofb, \ |
79ba130c |
321 | gencrypt, gencrypt, gdestroy, gsetiv, gbdry \ |
322 | }; \ |
323 | \ |
324 | const gccipher pre##_ofb = { \ |
2af20fa2 |
325 | #pre "-ofb", pre##_keysz, PRE##_BLKSZ, \ |
79ba130c |
326 | ginit \ |
327 | }; \ |
328 | \ |
329 | /* --- Generic random number generator interface --- */ \ |
330 | \ |
331 | typedef struct grctx { \ |
332 | grand r; \ |
333 | pre##_ofbctx k; \ |
334 | } grctx; \ |
335 | \ |
336 | static void grdestroy(grand *r) \ |
337 | { \ |
338 | grctx *g = (grctx *)r; \ |
2af20fa2 |
339 | BURN(*g); \ |
340 | S_DESTROY(g); \ |
79ba130c |
341 | } \ |
342 | \ |
343 | static int grmisc(grand *r, unsigned op, ...) \ |
344 | { \ |
345 | grctx *g = (grctx *)r; \ |
346 | va_list ap; \ |
347 | int rc = 0; \ |
348 | octet buf[PRE##_BLKSZ]; \ |
349 | va_start(ap, op); \ |
350 | \ |
351 | switch (op) { \ |
352 | case GRAND_CHECK: \ |
353 | switch (va_arg(ap, unsigned)) { \ |
354 | case GRAND_CHECK: \ |
355 | case GRAND_SEEDINT: \ |
356 | case GRAND_SEEDUINT32: \ |
357 | case GRAND_SEEDBLOCK: \ |
4ab1268f |
358 | case GRAND_SEEDRAND: \ |
79ba130c |
359 | rc = 1; \ |
360 | break; \ |
361 | default: \ |
362 | rc = 0; \ |
363 | break; \ |
364 | } \ |
365 | break; \ |
366 | case GRAND_SEEDINT: \ |
367 | memset(buf, 0, sizeof(buf)); \ |
368 | STORE32(buf, va_arg(ap, unsigned)); \ |
369 | pre##_ofbsetiv(&g->k, buf); \ |
370 | break; \ |
371 | case GRAND_SEEDUINT32: \ |
372 | memset(buf, 0, sizeof(buf)); \ |
373 | STORE32(buf, va_arg(ap, uint32)); \ |
374 | pre##_ofbsetiv(&g->k, buf); \ |
375 | break; \ |
376 | case GRAND_SEEDBLOCK: { \ |
377 | const void *p = va_arg(ap, const void *); \ |
378 | size_t sz = va_arg(ap, size_t); \ |
379 | if (sz < sizeof(buf)) { \ |
380 | memset(buf, 0, sizeof(buf)); \ |
381 | memcpy(buf, p, sz); \ |
382 | p = buf; \ |
383 | } \ |
384 | pre##_ofbsetiv(&g->k, p); \ |
385 | } break; \ |
4ab1268f |
386 | case GRAND_SEEDRAND: { \ |
387 | grand *rr = va_arg(ap, grand *); \ |
388 | rr->ops->fill(rr, buf, sizeof(buf)); \ |
389 | pre##_ofbsetiv(&g->k, buf); \ |
390 | } break; \ |
391 | default: \ |
392 | GRAND_BADOP; \ |
393 | break; \ |
79ba130c |
394 | } \ |
395 | \ |
396 | va_end(ap); \ |
397 | return (rc); \ |
398 | } \ |
399 | \ |
400 | static octet grbyte(grand *r) \ |
401 | { \ |
402 | grctx *g = (grctx *)r; \ |
403 | octet o; \ |
404 | pre##_ofbencrypt(&g->k, 0, &o, 1); \ |
405 | return (o); \ |
406 | } \ |
407 | \ |
408 | static uint32 grword(grand *r) \ |
409 | { \ |
410 | grctx *g = (grctx *)r; \ |
411 | octet b[4]; \ |
412 | pre##_ofbencrypt(&g->k, 0, b, sizeof(b)); \ |
413 | return (LOAD32(b)); \ |
414 | } \ |
415 | \ |
416 | static void grfill(grand *r, void *p, size_t sz) \ |
417 | { \ |
418 | grctx *g = (grctx *)r; \ |
419 | pre##_ofbencrypt(&g->k, 0, p, sz); \ |
420 | } \ |
421 | \ |
422 | static const grand_ops grops = { \ |
423 | #pre "-ofb", \ |
2af20fa2 |
424 | GRAND_CRYPTO, 0, \ |
79ba130c |
425 | grmisc, grdestroy, \ |
426 | grword, grbyte, grword, grand_range, grfill \ |
427 | }; \ |
428 | \ |
429 | /* --- @pre_ofbrand@ --- * \ |
430 | * \ |
431 | * Arguments: @const void *k@ = pointer to key material \ |
432 | * @size_t sz@ = size of key material \ |
433 | * \ |
434 | * Returns: Pointer to generic random number generator interface. \ |
435 | * \ |
436 | * Use: Creates a random number interface wrapper around an \ |
437 | * OFB-mode block cipher. \ |
438 | */ \ |
439 | \ |
440 | grand *pre##_ofbrand(const void *k, size_t sz) \ |
441 | { \ |
2af20fa2 |
442 | grctx *g = S_CREATE(grctx); \ |
79ba130c |
443 | g->r.ops = &grops; \ |
444 | pre##_ofbinit(&g->k, k, sz, 0); \ |
445 | return (&g->r); \ |
446 | } \ |
447 | \ |
448 | OFB_TEST(PRE, pre) |
449 | |
450 | /*----- Test rig ----------------------------------------------------------*/ |
451 | |
452 | #ifdef TEST_RIG |
453 | |
454 | #include <stdio.h> |
455 | |
456 | #include "daftstory.h" |
457 | |
458 | /* --- @OFB_TEST@ --- * |
459 | * |
460 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
461 | * |
462 | * Use: Standard test rig for OFB functions. |
463 | */ |
464 | |
465 | #define OFB_TEST(PRE, pre) \ |
466 | \ |
467 | /* --- Initial plaintext for the test --- */ \ |
468 | \ |
469 | static const octet text[] = TEXT; \ |
470 | \ |
471 | /* --- Key and IV to use --- */ \ |
472 | \ |
473 | static const octet key[] = KEY; \ |
474 | static const octet iv[] = IV; \ |
475 | \ |
476 | /* --- Buffers for encryption and decryption output --- */ \ |
477 | \ |
478 | static octet ct[sizeof(text)]; \ |
479 | static octet pt[sizeof(text)]; \ |
480 | \ |
481 | static void hexdump(const octet *p, size_t sz) \ |
482 | { \ |
483 | const octet *q = p + sz; \ |
484 | for (sz = 0; p < q; p++, sz++) { \ |
485 | printf("%02x", *p); \ |
486 | if ((sz + 1) % PRE##_BLKSZ == 0) \ |
487 | putchar(':'); \ |
488 | } \ |
489 | } \ |
490 | \ |
491 | int main(void) \ |
492 | { \ |
493 | size_t sz = 0, rest; \ |
494 | pre##_ofbctx ctx; \ |
495 | int status = 0; \ |
496 | int done = 0; \ |
497 | pre##_ctx k; \ |
498 | \ |
499 | size_t keysz = PRE##_KEYSZ ? \ |
500 | PRE##_KEYSZ : strlen((const char *)key); \ |
501 | \ |
502 | fputs(#pre "-ofb: ", stdout); \ |
503 | \ |
504 | pre##_init(&k, key, keysz); \ |
505 | pre##_ofbsetkey(&ctx, &k); \ |
506 | \ |
507 | while (sz <= sizeof(text)) { \ |
508 | rest = sizeof(text) - sz; \ |
509 | memcpy(ct, text, sizeof(text)); \ |
510 | pre##_ofbsetiv(&ctx, iv); \ |
511 | pre##_ofbencrypt(&ctx, ct, ct, sz); \ |
512 | pre##_ofbencrypt(&ctx, ct + sz, ct + sz, rest); \ |
513 | memcpy(pt, ct, sizeof(text)); \ |
514 | pre##_ofbsetiv(&ctx, iv); \ |
515 | pre##_ofbencrypt(&ctx, pt, pt, rest); \ |
516 | pre##_ofbencrypt(&ctx, pt + rest, pt + rest, sz); \ |
517 | if (memcmp(pt, text, sizeof(text)) == 0) { \ |
518 | done++; \ |
519 | if (sizeof(text) < 40 || done % 8 == 0) \ |
520 | fputc('.', stdout); \ |
521 | if (done % 480 == 0) \ |
522 | fputs("\n\t", stdout); \ |
523 | fflush(stdout); \ |
524 | } else { \ |
525 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ |
526 | status = 1; \ |
527 | printf("\tplaintext = "); hexdump(text, sz); \ |
528 | printf(", "); hexdump(text + sz, rest); \ |
529 | fputc('\n', stdout); \ |
530 | printf("\tciphertext = "); hexdump(ct, sz); \ |
531 | printf(", "); hexdump(ct + sz, rest); \ |
532 | fputc('\n', stdout); \ |
533 | printf("\trecovered text = "); hexdump(pt, sz); \ |
534 | printf(", "); hexdump(pt + sz, rest); \ |
535 | fputc('\n', stdout); \ |
536 | fputc('\n', stdout); \ |
537 | } \ |
538 | if (sz < 63) \ |
539 | sz++; \ |
540 | else \ |
541 | sz += 9; \ |
542 | } \ |
543 | \ |
544 | fputs(status ? " failed\n" : " ok\n", stdout); \ |
545 | return (status); \ |
546 | } |
547 | |
548 | #else |
549 | # define OFB_TEST(PRE, pre) |
550 | #endif |
551 | |
552 | /*----- That's all, folks -------------------------------------------------*/ |
553 | |
554 | #ifdef __cplusplus |
555 | } |
556 | #endif |
557 | |
558 | #endif |