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1 | /* -*-c-*- |
2 | * |
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3 | * The SEAL pseudo-random function family |
4 | * |
5 | * (c) 2000 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
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16 | * |
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17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include <assert.h> |
31 | #include <stdarg.h> |
32 | #include <stdio.h> |
33 | |
34 | #include <mLib/bits.h> |
35 | |
36 | #include "arena.h" |
37 | #include "gcipher.h" |
38 | #include "grand.h" |
39 | #include "paranoia.h" |
40 | #include "seal.h" |
41 | #include "sha.h" |
42 | |
43 | /*----- Global variables --------------------------------------------------*/ |
44 | |
45 | const octet seal_keysz[] = { KSZ_ANY, SHA_HASHSZ }; |
46 | |
47 | /*----- Main code ---------------------------------------------------------*/ |
48 | |
49 | /* --- @gamma@ --- * |
50 | * |
51 | * Arguments: @uint32 *p@ = output table |
52 | * @size_t sz@ = size of the output table |
53 | * @const void *k@ = pointer to key material |
54 | * @unsigned i@ = integer offset |
55 | * |
56 | * Returns: --- |
57 | * |
58 | * Use: Initializes a SEAL key table. |
59 | */ |
60 | |
61 | static void gamma(uint32 *p, size_t sz, const void *k, unsigned i) |
62 | { |
63 | uint32 buf[80] = { 0 }; |
64 | const octet *kk = k; |
65 | uint32 aa = LOAD32(kk); |
66 | uint32 bb = LOAD32(kk + 4); |
67 | uint32 cc = LOAD32(kk + 8); |
68 | uint32 dd = LOAD32(kk + 12); |
69 | uint32 ee = LOAD32(kk + 16); |
70 | |
71 | unsigned skip = i % 5; |
72 | i /= 5; |
73 | |
74 | /* --- While there's hashing to do, do hashing --- */ |
75 | |
76 | while (sz) { |
77 | uint32 a = aa, b = bb, c = cc, d = dd, e = ee; |
78 | int j; |
79 | |
80 | /* --- Initialize and expand the buffer --- */ |
81 | |
82 | buf[0] = i++; |
83 | |
84 | for (j = 16; j < 80; j++) { |
85 | uint32 x = buf[j - 3] ^ buf[j - 8] ^ buf[j - 14] ^ buf[j - 16]; |
86 | buf[j] = ROL32(x, 1); |
87 | } |
88 | |
89 | /* --- Definitions for round functions --- */ |
90 | |
91 | #define F(x, y, z) (((x) & (y)) | (~(x) & (z))) |
92 | #define G(x, y, z) ((x) ^ (y) ^ (z)) |
93 | #define H(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z))) |
94 | |
95 | #define T(v, w, x, y, z, i, f, k) do { \ |
96 | uint32 _x; \ |
97 | z = ROL32(v, 5) + f(w, x, y) + z + buf[i] + k; \ |
98 | w = ROR32(w, 2); \ |
99 | _x = v; v = z; z = y; y = x; x = w; w = _x; \ |
100 | } while (0) |
101 | |
102 | #define FF(v, w, x, y, z, i) T(v, w, x, y, z, i, F, 0x5a827999) |
103 | #define GG(v, w, x, y, z, i) T(v, w, x, y, z, i, G, 0x6ed9eba1) |
104 | #define HH(v, w, x, y, z, i) T(v, w, x, y, z, i, H, 0x8f1bbcdc) |
105 | #define II(v, w, x, y, z, i) T(v, w, x, y, z, i, G, 0xca62c1d6) |
106 | |
107 | /* --- The main compression function --- * |
108 | * |
109 | * Since this isn't doing bulk hashing, do it the easy way. |
110 | */ |
111 | |
112 | for (j = 0; j < 20; j++) |
113 | FF(a, b, c, d, e, j); |
114 | for (j = 20; j < 40; j++) |
115 | GG(a, b, c, d, e, j); |
116 | for (j = 40; j < 60; j++) |
117 | HH(a, b, c, d, e, j); |
118 | for (j = 60; j < 80; j++) |
119 | II(a, b, c, d, e, j); |
120 | |
121 | /* --- Do the chaining at the end --- */ |
122 | |
123 | a += aa; b += bb; c += cc; d += dd; e += ee; |
124 | |
125 | /* --- Write to the output buffer --- */ |
126 | |
127 | switch (skip) { |
128 | case 0: |
129 | if (sz) { *p++ = a; sz--; } |
130 | case 1: |
131 | if (sz) { *p++ = b; sz--; } |
132 | case 2: |
133 | if (sz) { *p++ = c; sz--; } |
134 | case 3: |
135 | if (sz) { *p++ = d; sz--; } |
136 | case 4: |
137 | if (sz) { *p++ = e; sz--; } |
138 | skip = 0; |
139 | } |
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140 | } |
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141 | } |
142 | |
143 | /* --- @seal_initkey@ --- * |
144 | * |
145 | * Arguments: @seal_key *k@ = pointer to key block |
146 | * @const void *buf@ = pointer to key material |
147 | * @size_t sz@ = size of the key material |
148 | * |
149 | * Returns: --- |
150 | * |
151 | * Use: Initializes a SEAL key block. The key material may be any |
152 | * size, but if it's not 20 bytes long it's passed to SHA for |
153 | * hashing first. |
154 | */ |
155 | |
156 | void seal_initkey(seal_key *k, const void *buf, size_t sz) |
157 | { |
158 | /* --- Hash the key if it's the wrong size --- */ |
159 | |
160 | if (sz == SHA_HASHSZ) |
161 | memcpy(k->k, buf, sizeof(k->k)); |
162 | else { |
163 | sha_ctx c; |
164 | sha_init(&c); |
165 | sha_hash(&c, buf, sz); |
166 | sha_done(&c, k->k); |
167 | } |
168 | |
169 | /* --- Expand the key to fit the various tables --- */ |
170 | |
171 | gamma(k->t, 512, k->k, 0); |
172 | gamma(k->s, 256, k->k, 0x1000); |
173 | gamma(k->r, SEAL_R, k->k, 0x2000); |
174 | } |
175 | |
176 | /* --- @seal_reset@ --- * |
177 | * |
178 | * Arguments: @seal_ctx *c@ = pointer to a SEAL context |
179 | * |
180 | * Returns: --- |
181 | * |
182 | * Use: Resets the context so that more data can be extracted from |
183 | * it. |
184 | */ |
185 | |
186 | static void seal_reset(seal_ctx *c) |
187 | { |
188 | seal_key *k = c->k; |
189 | uint32 n = c->n; |
190 | uint32 A, B, C, D; |
191 | unsigned p; |
192 | |
193 | /* --- Initialize the new chaining variables --- */ |
194 | |
195 | if (c->l >= SEAL_R) { |
196 | gamma(c->rbuf, SEAL_R, k->k, c->ri); |
197 | c->ri += SEAL_R; |
198 | c->l = 0; |
199 | c->r = c->rbuf; |
200 | } |
201 | |
202 | A = n ^ c->r[0]; |
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203 | B = ROR32(n, 8) ^ c->r[1]; |
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204 | C = ROR32(n, 16) ^ c->r[2]; |
205 | D = ROR32(n, 24) ^ c->r[3]; |
206 | c->l += 4; |
207 | c->r += 4; |
208 | |
209 | /* --- Ensure that everything is sufficiently diffused --- */ |
210 | |
211 | p = A & 0x7fc; B += k->t[p >> 2]; A = ROR32(A, 9); |
212 | p = B & 0x7fc; C += k->t[p >> 2]; B = ROR32(B, 9); |
213 | p = C & 0x7fc; D += k->t[p >> 2]; C = ROR32(C, 9); |
214 | p = D & 0x7fc; A += k->t[p >> 2]; D = ROR32(D, 9); |
215 | p = A & 0x7fc; B += k->t[p >> 2]; A = ROR32(A, 9); |
216 | p = B & 0x7fc; C += k->t[p >> 2]; B = ROR32(B, 9); |
217 | p = C & 0x7fc; D += k->t[p >> 2]; C = ROR32(C, 9); |
218 | p = D & 0x7fc; A += k->t[p >> 2]; D = ROR32(D, 9); |
219 | |
220 | /* --- Write out some context --- */ |
221 | |
222 | c->n1 = D; c->n2 = B; c->n3 = A; c->n4 = C; |
223 | |
224 | /* --- Diffuse some more --- */ |
225 | |
226 | p = A & 0x7fc; B += k->t[p >> 2]; A = ROR32(A, 9); |
227 | p = B & 0x7fc; C += k->t[p >> 2]; B = ROR32(B, 9); |
228 | p = C & 0x7fc; D += k->t[p >> 2]; C = ROR32(C, 9); |
229 | p = D & 0x7fc; A += k->t[p >> 2]; D = ROR32(D, 9); |
230 | |
231 | /* --- Write out the magic numbers --- */ |
232 | |
233 | c->a = A; c->b = B; c->c = C; c->d = D; |
234 | c->i = 0; |
235 | } |
236 | |
237 | /* --- @seal_initctx@ --- * |
238 | * |
239 | * Arguments: @seal_ctx *c@ = pointer to a SEAL context |
240 | * @seal_key *k@ = pointer to a SEAL key |
241 | * @uint32 n@ = integer sequence number |
242 | * |
243 | * Returns: --- |
244 | * |
245 | * Use: Initializes a SEAL context which can be used for random |
246 | * number generation or whatever. |
247 | */ |
248 | |
249 | void seal_initctx(seal_ctx *c, seal_key *k, uint32 n) |
250 | { |
251 | c->k = k; |
252 | c->n = n; |
253 | c->l = 0; |
254 | c->r = k->r; |
255 | c->ri = 0x2000 + SEAL_R; |
256 | c->qsz = 0; |
257 | seal_reset(c); |
258 | } |
259 | |
260 | /* --- @seal_encrypt@ --- * |
261 | * |
262 | * Arguments: @seal_ctx *c@ = pointer to a SEAL context |
263 | * @const void *src@ = pointer to source data |
264 | * @void *dest@ = pointer to destination data |
265 | * @size_t sz@ = size of the data |
266 | * |
267 | * Returns: --- |
268 | * |
269 | * Use: Encrypts a block of data using SEAL. If @src@ is zero, |
270 | * @dest@ is filled with SEAL output. If @dest@ is zero, the |
271 | * SEAL generator is just spun around for a bit. This shouldn't |
272 | * be necessary, because SEAL isn't RC4. |
273 | */ |
274 | |
275 | void seal_encrypt(seal_ctx *c, const void *src, void *dest, size_t sz) |
276 | { |
277 | const octet *s = src; |
278 | octet *d = dest; |
279 | |
280 | /* --- Expect a big dollop of bytes --- */ |
281 | |
282 | if (sz > c->qsz) { |
283 | seal_key *k = c->k; |
284 | uint32 A = c->a, B = c->b, C = c->c, D = c->d; |
285 | uint32 n1 = c->n1, n2 = c->n2, n3 = c->n3, n4 = c->n4; |
286 | uint32 aa, bb, cc, dd; |
287 | unsigned j = c->i; |
288 | |
289 | /* --- Empty the queue first --- */ |
290 | |
291 | if (c->qsz) { |
292 | if (d) { |
293 | unsigned i; |
294 | octet *p = c->q + sizeof(c->q) - c->qsz; |
295 | for (i = 0; i < c->qsz; i++) |
296 | *d++ = (s ? *s++ ^ *p++ : *p++); |
297 | } |
298 | sz -= c->qsz; |
299 | } |
300 | |
301 | /* --- Main sequence --- */ |
302 | |
303 | for (;;) { |
304 | unsigned P, Q; |
305 | |
306 | /* --- Reset if we've run out of steam on this iteration --- */ |
307 | |
308 | if (j == 256) { |
309 | seal_reset(c); |
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310 | A = c->a, B = c->b, C = c->c, D = c->d; |
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311 | n1 = c->n1, n2 = c->n2, n3 = c->n3, n4 = c->n4; |
312 | j = 0; |
313 | } |
314 | |
315 | /* --- Make some new numbers --- */ |
316 | |
317 | P = A & 0x7fc; B += k->t[P >> 2]; A = ROR32(A, 9); B ^= A; |
318 | Q = B & 0x7fc; C ^= k->t[Q >> 2]; B = ROR32(B, 9); C += B; |
319 | P = (P + C) & 0x7fc; D += k->t[P >> 2]; C = ROR32(C, 9); D ^= C; |
320 | Q = (Q + D) & 0x7fc; A ^= k->t[Q >> 2]; D = ROR32(D, 9); A += D; |
321 | P = (P + A) & 0x7fc; B ^= k->t[P >> 2]; A = ROR32(A, 9); |
322 | Q = (Q + B) & 0x7fc; C += k->t[Q >> 2]; B = ROR32(B, 9); |
323 | P = (P + C) & 0x7fc; D ^= k->t[P >> 2]; C = ROR32(C, 9); |
324 | Q = (Q + D) & 0x7fc; A += k->t[Q >> 2]; D = ROR32(D, 9); |
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325 | |
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326 | /* --- Remember the output and set up the next round --- */ |
327 | |
328 | aa = B + k->s[j + 0]; |
329 | bb = C ^ k->s[j + 1]; |
330 | cc = D + k->s[j + 2]; |
331 | dd = A ^ k->s[j + 3]; |
332 | j += 4; |
333 | |
334 | if (j & 4) |
335 | A += n1, B += n2, C ^= n1, D ^= n2; |
336 | else |
337 | A += n3, B += n4, C ^= n3, D ^= n4; |
338 | |
339 | /* --- Bail out here if we need to do buffering --- */ |
340 | |
341 | if (sz < 16) |
342 | break; |
343 | |
344 | /* --- Write the next 16 bytes --- */ |
345 | |
346 | if (d) { |
347 | if (s) { |
348 | aa ^= LOAD32_L(s + 0); |
349 | bb ^= LOAD32_L(s + 4); |
350 | cc ^= LOAD32_L(s + 8); |
351 | dd ^= LOAD32_L(s + 12); |
352 | s += 16; |
353 | } |
354 | STORE32_L(d + 0, aa); |
355 | STORE32_L(d + 4, bb); |
356 | STORE32_L(d + 8, cc); |
357 | STORE32_L(d + 12, dd); |
358 | d += 16; |
359 | } |
360 | sz -= 16; |
361 | } |
362 | |
363 | /* --- Write the new queue --- */ |
364 | |
365 | STORE32_L(c->q + 0, aa); |
366 | STORE32_L(c->q + 4, bb); |
367 | STORE32_L(c->q + 8, cc); |
368 | STORE32_L(c->q + 12, dd); |
369 | c->qsz = 16; |
370 | |
371 | c->a = A; c->b = B; c->c = C; c->d = D; |
372 | c->i = j; |
373 | } |
374 | |
375 | /* --- Deal with the rest from the queue --- */ |
376 | |
377 | if (sz) { |
378 | unsigned i; |
379 | octet *p = c->q + sizeof(c->q) - c->qsz; |
380 | if (d) { |
381 | for (i = 0; i < sz; i++) |
382 | *d++ = (s ? *s++ ^ *p++ : *p++); |
383 | } |
384 | c->qsz -= sz; |
385 | } |
386 | } |
387 | |
388 | /*----- Generic cipher interface ------------------------------------------*/ |
389 | |
390 | typedef struct gctx { |
391 | gcipher c; |
392 | seal_key k; |
393 | seal_ctx cc; |
394 | } gctx; |
395 | |
396 | static const gcipher_ops gops; |
397 | |
398 | static gcipher *ginit(const void *k, size_t sz) |
399 | { |
400 | gctx *g = S_CREATE(gctx); |
401 | g->c.ops = &gops; |
402 | seal_initkey(&g->k, k, sz); |
403 | seal_initctx(&g->cc, &g->k, 0); |
404 | return (&g->c); |
405 | } |
406 | |
407 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) |
408 | { |
409 | gctx *g = (gctx *)c; |
410 | seal_encrypt(&g->cc, s, t, sz); |
411 | } |
412 | |
413 | static void gsetiv(gcipher *c, const void *iv) |
414 | { |
415 | gctx *g = (gctx *)c; |
416 | uint32 n = *(const uint32 *)iv; |
417 | seal_initctx(&g->cc, &g->k, n); |
418 | } |
419 | |
420 | static void gdestroy(gcipher *c) |
421 | { |
422 | gctx *g = (gctx *)c; |
423 | BURN(*g); |
424 | S_DESTROY(g); |
425 | } |
426 | |
427 | static const gcipher_ops gops = { |
428 | &seal, |
429 | gencrypt, gencrypt, gdestroy, gsetiv, 0 |
430 | }; |
431 | |
432 | const gccipher seal = { |
433 | "seal", seal_keysz, 0, |
434 | ginit |
435 | }; |
436 | |
437 | /*----- Generic random number generator interface -------------------------*/ |
438 | |
439 | typedef struct grctx { |
440 | grand r; |
441 | seal_key k; |
442 | seal_ctx cc; |
443 | } grctx; |
444 | |
445 | static void grdestroy(grand *r) |
446 | { |
447 | grctx *g = (grctx *)r; |
448 | BURN(*g); |
449 | S_DESTROY(g); |
450 | } |
451 | |
452 | static int grmisc(grand *r, unsigned op, ...) |
453 | { |
454 | grctx *g = (grctx *)r; |
455 | va_list ap; |
456 | int rc = 0; |
457 | va_start(ap, op); |
458 | |
459 | switch (op) { |
460 | case GRAND_CHECK: |
461 | switch (va_arg(ap, unsigned)) { |
462 | case GRAND_CHECK: |
463 | case GRAND_SEEDINT: |
464 | case GRAND_SEEDUINT32: |
465 | case GRAND_SEEDBLOCK: |
466 | case GRAND_SEEDRAND: |
467 | rc = 1; |
468 | break; |
469 | default: |
470 | rc = 0; |
471 | break; |
472 | } |
473 | break; |
474 | case GRAND_SEEDINT: |
475 | seal_initctx(&g->cc, &g->k, va_arg(ap, int)); |
476 | break; |
477 | case GRAND_SEEDUINT32: |
478 | seal_initctx(&g->cc, &g->k, va_arg(ap, uint32)); |
479 | break; |
480 | case GRAND_SEEDBLOCK: { |
481 | const void *p = va_arg(ap, const void *); |
482 | size_t sz = va_arg(ap, size_t); |
483 | uint32 n; |
484 | if (sz >= 4) |
485 | n = LOAD32_L(p); |
486 | else { |
487 | octet buf[4] = { 0 }; |
488 | memcpy(buf, p, sz); |
489 | n = LOAD32_L(p); |
490 | } |
491 | seal_initctx(&g->cc, &g->k, n); |
492 | } break; |
493 | case GRAND_SEEDRAND: { |
494 | grand *rr = va_arg(ap, grand *); |
495 | seal_initctx(&g->cc, &g->k, rr->ops->word(rr)); |
496 | } break; |
497 | default: |
498 | GRAND_BADOP; |
499 | break; |
500 | } |
501 | |
502 | va_end(ap); |
503 | return (rc); |
504 | } |
505 | |
506 | static octet grbyte(grand *r) |
507 | { |
508 | grctx *g = (grctx *)r; |
509 | octet o; |
510 | seal_encrypt(&g->cc, 0, &o, 1); |
511 | return (o); |
512 | } |
513 | |
514 | static uint32 grword(grand *r) |
515 | { |
516 | grctx *g = (grctx *)r; |
517 | octet b[4]; |
518 | seal_encrypt(&g->cc, 0, b, 4); |
519 | return (LOAD32(b)); |
520 | } |
521 | |
522 | static void grfill(grand *r, void *p, size_t sz) |
523 | { |
524 | grctx *g = (grctx *)r; |
525 | seal_encrypt(&g->cc, 0, p, sz); |
526 | } |
527 | |
528 | static const grand_ops grops = { |
529 | "seal", |
530 | GRAND_CRYPTO, 0, |
531 | grmisc, grdestroy, |
532 | grword, grbyte, grword, grand_range, grfill |
533 | }; |
534 | |
535 | /* --- @seal_rand@ --- * |
536 | * |
537 | * Arguments: @const void *k@ = pointer to key material |
538 | * @size_t sz@ = size of key material |
539 | * @uint32 n@ = sequence number |
540 | * |
541 | * Returns: Pointer to generic random number generator interface. |
542 | * |
543 | * Use: Creates a random number interface wrapper around a SEAL |
544 | * pseudorandom function. |
545 | */ |
546 | |
547 | grand *seal_rand(const void *k, size_t sz, uint32 n) |
548 | { |
549 | grctx *g = S_CREATE(grctx); |
550 | g->r.ops = &grops; |
551 | seal_initkey(&g->k, k, sz); |
552 | seal_initctx(&g->cc, &g->k, n); |
553 | return (&g->r); |
554 | } |
555 | |
556 | /*----- Test rig ----------------------------------------------------------*/ |
557 | |
558 | #ifdef TEST_RIG |
559 | |
560 | #include <string.h> |
561 | |
562 | #include <mLib/testrig.h> |
563 | |
564 | static int verify(dstr *v) |
565 | { |
566 | seal_key k; |
567 | seal_ctx c; |
568 | uint32 n = *(uint32 *)v[1].buf; |
569 | dstr d = DSTR_INIT; |
570 | dstr z = DSTR_INIT; |
571 | int i; |
572 | int ok = 1; |
573 | |
574 | DENSURE(&d, v[2].len); |
575 | DENSURE(&z, v[2].len); |
576 | memset(z.buf, 0, v[2].len); |
577 | z.len = d.len = v[2].len; |
578 | seal_initkey(&k, v[0].buf, v[0].len); |
579 | |
580 | for (i = 0; i < v[2].len; i++) { |
581 | seal_initctx(&c, &k, n); |
582 | seal_encrypt(&c, 0, d.buf, i); |
583 | seal_encrypt(&c, z.buf, d.buf + i, d.len - i); |
584 | if (memcmp(d.buf, v[2].buf, d.len) != 0) { |
585 | ok = 0; |
586 | printf("*** seal failure\n"); |
587 | printf("*** k = "); type_hex.dump(&v[0], stdout); putchar('\n'); |
588 | printf("*** n = %08lx\n", (unsigned long)n); |
589 | printf("*** i = %i\n", i); |
590 | printf("*** expected = "); type_hex.dump(&v[2], stdout); putchar('\n'); |
591 | printf("*** computed = "); type_hex.dump(&d, stdout); putchar('\n'); |
592 | } |
593 | } |
594 | |
595 | dstr_destroy(&d); |
596 | dstr_destroy(&z); |
597 | |
598 | return (ok); |
599 | } |
600 | |
601 | static test_chunk defs[] = { |
602 | { "seal", verify, { &type_hex, &type_uint32, &type_hex, 0 } }, |
603 | { 0, 0, { 0 } } |
604 | }; |
605 | |
606 | int main(int argc, char *argv[]) |
607 | { |
0f00dc4c |
608 | test_run(argc, argv, defs, SRCDIR"/t/seal"); |
8dd8c294 |
609 | return (0); |
610 | } |
611 | |
612 | #endif |
613 | |
614 | /*----- That's all, folks -------------------------------------------------*/ |