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1 | /* -*-c-*- |
2 | * |
b817bfc6 |
3 | * $Id: dsa-gen.c,v 1.10 2004/04/08 01:36:15 mdw Exp $ |
8b810a45 |
4 | * |
5 | * Generate DSA shared parameters |
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 | |
8b810a45 |
30 | /*----- Header files ------------------------------------------------------*/ |
31 | |
32 | #include <stdio.h> |
33 | #include <stdlib.h> |
34 | |
35 | #include "dsa.h" |
b04a7659 |
36 | #include "dsarand.h" |
ef5f4810 |
37 | #include "fibrand.h" |
8b810a45 |
38 | #include "mp.h" |
ef5f4810 |
39 | #include "mprand.h" |
8b810a45 |
40 | #include "pgen.h" |
b04a7659 |
41 | #include "prim.h" |
8b810a45 |
42 | #include "sha.h" |
43 | |
b04a7659 |
44 | /*----- The DSA stepper ---------------------------------------------------*/ |
8b810a45 |
45 | |
b04a7659 |
46 | /* --- @next@ --- * |
8b810a45 |
47 | * |
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48 | * Arguments: @pgen_event *ev@ = pointer to event block |
49 | * @dsa_stepctx *d@ = pointer to stepping context |
8b810a45 |
50 | * |
b04a7659 |
51 | * Returns: A @PGEN@ result code. |
8b810a45 |
52 | * |
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53 | * Use: Steps the generator once, reads the result, and tests it. |
8b810a45 |
54 | */ |
55 | |
b04a7659 |
56 | static int next(pgen_event *ev, dsa_stepctx *d) |
8b810a45 |
57 | { |
b04a7659 |
58 | mp *m; |
59 | int rc; |
8b810a45 |
60 | |
b04a7659 |
61 | /* --- Load the new candidate --- */ |
8b810a45 |
62 | |
a63f764a |
63 | if (d->seedbuf) |
64 | d->r->ops->misc(d->r, DSARAND_GETSEED, d->seedbuf); |
65 | m = mprand(ev->m, d->bits, d->r, 0); |
8b810a45 |
66 | |
b04a7659 |
67 | /* --- Force to be a multiple of @q@ --- */ |
ef5f4810 |
68 | |
b04a7659 |
69 | if (d->q) { |
70 | mp *r = MP_NEW; |
71 | mp_div(0, &r, m, d->q); |
72 | m = mp_sub(m, m, r); |
73 | mp_drop(r); |
8b810a45 |
74 | } |
b04a7659 |
75 | m->v[0] |= d->or; |
76 | ev->m = m; |
8b810a45 |
77 | |
b04a7659 |
78 | /* --- Do the trial division --- */ |
8b810a45 |
79 | |
8a33545f |
80 | rc = pfilt_smallfactor(m); |
a63f764a |
81 | d->count++; |
8b810a45 |
82 | |
b04a7659 |
83 | /* --- Return the result --- */ |
8b810a45 |
84 | |
b04a7659 |
85 | return (rc); |
86 | } |
8b810a45 |
87 | |
b04a7659 |
88 | /* --- @dsa_step@ --- */ |
89 | |
90 | int dsa_step(int rq, pgen_event *ev, void *p) |
91 | { |
92 | dsa_stepctx *d = p; |
93 | |
94 | switch (rq) { |
95 | case PGEN_BEGIN: |
b04a7659 |
96 | case PGEN_TRY: |
97 | return (next(ev, d)); |
98 | case PGEN_DONE: |
99 | return (PGEN_DONE); |
8b810a45 |
100 | } |
b04a7659 |
101 | return (PGEN_ABORT); |
102 | } |
8b810a45 |
103 | |
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104 | /*----- Glue code ---------------------------------------------------------*/ |
8b810a45 |
105 | |
2b31b269 |
106 | /* --- @dsa_gen@ --- * |
b04a7659 |
107 | * |
108 | * Arguments: @dsa_param *dp@ = where to store parameters |
109 | * @unsigned ql@ = length of @q@ in bits |
110 | * @unsigned pl@ = length of @p@ in bits |
111 | * @unsigned steps@ = number of steps to find @q@ |
112 | * @const void *k@ = pointer to key material |
113 | * @size_t sz@ = size of key material |
a63f764a |
114 | * @dsa_seed *ds@ = optional pointer for output seed information |
b04a7659 |
115 | * @pgen_proc *event@ = event handler function |
116 | * @void *ectx@ = argument for event handler |
117 | * |
118 | * Returns: @PGEN_DONE@ if everything worked ok; @PGEN_ABORT@ otherwise. |
119 | * |
120 | * Use: Generates the DSA shared parameters from a given seed value. |
052b36d0 |
121 | * |
122 | * The parameters are a prime %$q$%, relatively small, and a |
123 | * large prime %$p = kq + 1$% for some %$k$%, together with a |
124 | * generator %$g$% of the cyclic subgroup of order %$q$%. These |
125 | * are actually the same as the Diffie-Hellman parameter set, |
126 | * but the generation algorithm is different. |
b04a7659 |
127 | * |
128 | * The algorithm used is a compatible extension of the method |
129 | * described in the DSA standard, FIPS 186. The standard |
130 | * requires that %$q$% be 160 bits in size (i.e., @ql == 160@) |
131 | * and that the length of %$p$% be %$L = 512 + 64l$% for some |
132 | * %$l$%. Neither limitation applies to this implementation. |
133 | */ |
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134 | |
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135 | int dsa_gen(dsa_param *dp, unsigned ql, unsigned pl, unsigned steps, |
a63f764a |
136 | const void *k, size_t sz, dsa_seed *ds, |
137 | pgen_proc *event, void *ectx) |
b04a7659 |
138 | { |
139 | dsa_stepctx s; |
140 | prim_ctx p; |
141 | int i; |
142 | rabin r; |
143 | mp *qc; |
8b810a45 |
144 | |
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145 | /* --- Initialize the stepping context --- */ |
8b810a45 |
146 | |
b04a7659 |
147 | s.r = dsarand_create(k, sz); |
8b810a45 |
148 | |
b04a7659 |
149 | /* --- Find @q@ --- */ |
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150 | |
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151 | s.q = 0; |
152 | s.r->ops->misc(s.r, DSARAND_PASSES, 2); |
153 | s.bits = ql; |
a63f764a |
154 | s.count = 0; |
155 | s.or = 1; |
156 | if (!ds) |
157 | s.seedbuf = 0; |
158 | else { |
159 | ds->sz = sz; |
160 | ds->p = s.seedbuf = xmalloc(sz); |
161 | } |
b04a7659 |
162 | if ((dp->q = pgen("q", MP_NEW, MP_NEW, event, ectx, steps, dsa_step, &s, |
163 | rabin_iters(ql), pgen_test, &r)) == 0) |
164 | goto fail_q; |
8b810a45 |
165 | |
b04a7659 |
166 | /* --- Find @p@ --- */ |
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167 | |
a63f764a |
168 | s.count = ~0; |
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169 | s.q = mp_lsl(MP_NEW, dp->q, 1); |
170 | s.r->ops->misc(s.r, DSARAND_PASSES, 1); |
171 | s.bits = pl; |
a63f764a |
172 | s.seedbuf = 0; |
b04a7659 |
173 | if ((dp->p = pgen("p", MP_NEW, MP_NEW, event, ectx, 4096, dsa_step, &s, |
174 | rabin_iters(pl), pgen_test, &r)) == 0) |
175 | goto fail_p; |
176 | mp_drop(s.q); |
a63f764a |
177 | if (ds) |
178 | ds->count = s.count; |
b04a7659 |
179 | |
180 | /* --- Find @g@ --- * |
181 | * |
182 | * The division returns remainder 1. This doesn't matter. |
183 | */ |
184 | |
185 | mpmont_create(&p.mm, dp->p); |
186 | qc = MP_NEW; mp_div(&qc, 0, dp->p, dp->q); |
187 | i = 0; |
2b31b269 |
188 | p.exp = qc; |
b04a7659 |
189 | p.n = 0; |
190 | if ((dp->g = pgen("g", MP_NEW, MP_NEW, event, ectx, 0, prim_step, &i, |
191 | 1, prim_test, &p)) == 0) |
192 | goto fail_g; |
193 | |
194 | /* --- Done --- */ |
195 | |
196 | mp_drop(qc); |
197 | mpmont_destroy(&p.mm); |
198 | s.r->ops->destroy(s.r); |
199 | return (PGEN_DONE); |
200 | |
201 | /* --- Tidy up when things go wrong --- */ |
202 | |
203 | fail_g: |
204 | mp_drop(qc); |
205 | mpmont_destroy(&p.mm); |
206 | fail_p: |
207 | mp_drop(dp->q); |
208 | mp_drop(s.q); |
209 | fail_q: |
210 | s.r->ops->destroy(s.r); |
a63f764a |
211 | if (ds) |
212 | xfree(ds->p); |
b04a7659 |
213 | return (PGEN_ABORT); |
8b810a45 |
214 | } |
215 | |
b04a7659 |
216 | /*----- Test rig ----------------------------------------------------------*/ |
217 | |
218 | #ifdef TEST_RIG |
219 | |
8b810a45 |
220 | static int verify(dstr *v) |
221 | { |
a63f764a |
222 | mp *q = *(mp **)v[4].buf; |
223 | mp *p = *(mp **)v[5].buf; |
224 | mp *g = *(mp **)v[6].buf; |
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225 | dsa_param dp; |
a63f764a |
226 | dsa_seed ds; |
227 | unsigned long l = *(unsigned long *)v[1].buf; |
228 | unsigned long n = *(unsigned long *)v[3].buf; |
8b810a45 |
229 | int ok = 1; |
230 | int rc; |
a63f764a |
231 | keycheck kc; |
232 | keycheck_reportctx kcr; |
8b810a45 |
233 | |
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234 | rc = dsa_gen(&dp, 160, l, 16, v[0].buf, v[0].len, &ds, pgen_evspin, 0); |
235 | if (rc || ds.count != n || ds.sz != v[2].len || |
236 | memcmp(ds.p, v[2].buf, v[2].len) != 0 || |
237 | !MP_EQ(q, dp.q) || !MP_EQ(p, dp.p) || !MP_EQ(g, dp.g)) { |
8b810a45 |
238 | fputs("\n*** gen failed", stderr); |
a63f764a |
239 | fputs("\nseed_in = ", stderr); type_hex.dump(&v[0], stderr); |
240 | fprintf(stderr, "\nl = %lu", l); |
241 | fputs("\nseed_out = ", stderr); type_hex.dump(&v[2], stderr); |
242 | fprintf(stderr, "\ncount = %lu", n); |
8b810a45 |
243 | fputs("\n q = ", stderr); mp_writefile(q, stderr, 16); |
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244 | fputs("\n p = ", stderr); mp_writefile(p, stderr, 16); |
8b810a45 |
245 | fputs("\n g = ", stderr); mp_writefile(g, stderr, 16); |
246 | if (!rc) { |
a63f764a |
247 | dstr d; |
248 | d.buf = ds.p; d.len = ds.sz; |
249 | fputs("\nds.seed = ", stderr); type_hex.dump(&d, stderr); |
250 | fprintf(stderr, "\nds.count = %u", ds.count); |
8b810a45 |
251 | fputs("\ndp.q = ", stderr); mp_writefile(dp.q, stderr, 16); |
252 | fputs("\ndp.p = ", stderr); mp_writefile(dp.p, stderr, 16); |
253 | fputs("\ndp.g = ", stderr); mp_writefile(dp.g, stderr, 16); |
254 | } |
255 | fputc('\n', stderr); |
256 | ok = 0; |
257 | } |
258 | |
a63f764a |
259 | kcr.fp = stderr; |
260 | kcr.sev = KCSEV_ERR; |
261 | keycheck_init(&kc, keycheck_stdreport, &kcr); |
262 | if (!rc) |
263 | dsa_checkparam(&kc, &dp, &ds); |
264 | if (!keycheck_allclear(&kc, KCSEV_ERR)) { |
265 | fputs("\n*** gen failed check", stderr); |
266 | fputs("\nseed_in = ", stderr); type_hex.dump(&v[0], stderr); |
267 | fprintf(stderr, "\nl = %lu", l); |
268 | fputs("\nseed_out = ", stderr); type_hex.dump(&v[2], stderr); |
269 | fprintf(stderr, "\ncount = %lu", n); |
270 | fputs("\n q = ", stderr); mp_writefile(q, stderr, 16); |
271 | fputs("\n p = ", stderr); mp_writefile(p, stderr, 16); |
272 | fputs("\n g = ", stderr); mp_writefile(g, stderr, 16); |
273 | fputc('\n', stderr); |
274 | ok = 0; |
275 | } |
276 | |
8b810a45 |
277 | mp_drop(q); mp_drop(p); mp_drop(g); |
278 | if (!rc) { |
a63f764a |
279 | mp_drop(dp.q); mp_drop(dp.p); mp_drop(dp.g); xfree(ds.p); |
8b810a45 |
280 | } |
8a33545f |
281 | assert(mparena_count(MPARENA_GLOBAL) == 0); |
8b810a45 |
282 | return (ok); |
283 | } |
284 | |
285 | static test_chunk tests[] = { |
286 | { "gen", verify, |
a63f764a |
287 | { &type_hex, &type_ulong, &type_hex, &type_ulong, |
288 | &type_mp, &type_mp, &type_mp, 0 } }, |
8b810a45 |
289 | { 0, 0, { 0 } } |
290 | }; |
291 | |
292 | int main(int argc, char *argv[]) |
293 | { |
294 | sub_init(); |
295 | test_run(argc, argv, tests, SRCDIR "/tests/dsa"); |
296 | return (0); |
297 | } |
298 | |
299 | #endif |
300 | |
301 | /*----- That's all, folks -------------------------------------------------*/ |