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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: dsa-gen.c,v 1.9 2001/02/03 16:09:29 mdw Exp $ |
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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 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: dsa-gen.c,v $ |
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33 | * Revision 1.9 2001/02/03 16:09:29 mdw |
34 | * Allow the caller to fetch the parameter generation seed and counter. |
35 | * |
7d71fd1a |
36 | * Revision 1.8 2000/10/08 12:12:47 mdw |
37 | * Use @MP_EQ@ instead of @MP_CMP@. Remove vestages of @primorial@. |
38 | * |
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39 | * Revision 1.7 2000/08/15 21:45:05 mdw |
40 | * Use the new trial division equipment in pfilt. This gives a 10% |
41 | * performance improvement in dsa-gen.t. |
42 | * |
2b31b269 |
43 | * Revision 1.6 2000/07/29 10:00:14 mdw |
44 | * Rename `dsa_seed' to `dsa_gen' for consistency with other parameter- |
45 | * generation interfaces. |
46 | * |
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47 | * Revision 1.5 2000/02/12 18:21:02 mdw |
48 | * Overhaul of key management (again). |
49 | * |
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50 | * Revision 1.4 1999/12/22 15:52:44 mdw |
51 | * Reworking for new prime-search system. |
52 | * |
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53 | * Revision 1.3 1999/12/10 23:18:38 mdw |
54 | * Change interface for suggested destinations. |
55 | * |
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56 | * Revision 1.2 1999/11/20 22:23:48 mdw |
57 | * Allow event handler to abort the search process. |
58 | * |
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59 | * Revision 1.1 1999/11/19 19:28:00 mdw |
60 | * Implementation of the Digital Signature Algorithm. |
61 | * |
62 | */ |
63 | |
64 | /*----- Header files ------------------------------------------------------*/ |
65 | |
66 | #include <stdio.h> |
67 | #include <stdlib.h> |
68 | |
69 | #include "dsa.h" |
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70 | #include "dsarand.h" |
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71 | #include "fibrand.h" |
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72 | #include "mp.h" |
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73 | #include "mprand.h" |
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74 | #include "pgen.h" |
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75 | #include "prim.h" |
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76 | #include "sha.h" |
77 | |
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78 | /*----- The DSA stepper ---------------------------------------------------*/ |
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79 | |
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80 | /* --- @next@ --- * |
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81 | * |
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82 | * Arguments: @pgen_event *ev@ = pointer to event block |
83 | * @dsa_stepctx *d@ = pointer to stepping context |
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84 | * |
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85 | * Returns: A @PGEN@ result code. |
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86 | * |
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87 | * Use: Steps the generator once, reads the result, and tests it. |
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88 | */ |
89 | |
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90 | static int next(pgen_event *ev, dsa_stepctx *d) |
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91 | { |
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92 | mp *m; |
93 | int rc; |
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94 | |
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95 | /* --- Load the new candidate --- */ |
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96 | |
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97 | if (d->seedbuf) |
98 | d->r->ops->misc(d->r, DSARAND_GETSEED, d->seedbuf); |
99 | m = mprand(ev->m, d->bits, d->r, 0); |
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100 | |
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101 | /* --- Force to be a multiple of @q@ --- */ |
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102 | |
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103 | if (d->q) { |
104 | mp *r = MP_NEW; |
105 | mp_div(0, &r, m, d->q); |
106 | m = mp_sub(m, m, r); |
107 | mp_drop(r); |
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108 | } |
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109 | m->v[0] |= d->or; |
110 | ev->m = m; |
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111 | |
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112 | /* --- Do the trial division --- */ |
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113 | |
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114 | rc = pfilt_smallfactor(m); |
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115 | d->count++; |
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116 | |
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117 | /* --- Return the result --- */ |
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118 | |
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119 | return (rc); |
120 | } |
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121 | |
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122 | /* --- @dsa_step@ --- */ |
123 | |
124 | int dsa_step(int rq, pgen_event *ev, void *p) |
125 | { |
126 | dsa_stepctx *d = p; |
127 | |
128 | switch (rq) { |
129 | case PGEN_BEGIN: |
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130 | case PGEN_TRY: |
131 | return (next(ev, d)); |
132 | case PGEN_DONE: |
133 | return (PGEN_DONE); |
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134 | } |
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135 | return (PGEN_ABORT); |
136 | } |
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137 | |
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138 | /*----- Glue code ---------------------------------------------------------*/ |
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139 | |
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140 | /* --- @dsa_gen@ --- * |
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141 | * |
142 | * Arguments: @dsa_param *dp@ = where to store parameters |
143 | * @unsigned ql@ = length of @q@ in bits |
144 | * @unsigned pl@ = length of @p@ in bits |
145 | * @unsigned steps@ = number of steps to find @q@ |
146 | * @const void *k@ = pointer to key material |
147 | * @size_t sz@ = size of key material |
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148 | * @dsa_seed *ds@ = optional pointer for output seed information |
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149 | * @pgen_proc *event@ = event handler function |
150 | * @void *ectx@ = argument for event handler |
151 | * |
152 | * Returns: @PGEN_DONE@ if everything worked ok; @PGEN_ABORT@ otherwise. |
153 | * |
154 | * Use: Generates the DSA shared parameters from a given seed value. |
052b36d0 |
155 | * |
156 | * The parameters are a prime %$q$%, relatively small, and a |
157 | * large prime %$p = kq + 1$% for some %$k$%, together with a |
158 | * generator %$g$% of the cyclic subgroup of order %$q$%. These |
159 | * are actually the same as the Diffie-Hellman parameter set, |
160 | * but the generation algorithm is different. |
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161 | * |
162 | * The algorithm used is a compatible extension of the method |
163 | * described in the DSA standard, FIPS 186. The standard |
164 | * requires that %$q$% be 160 bits in size (i.e., @ql == 160@) |
165 | * and that the length of %$p$% be %$L = 512 + 64l$% for some |
166 | * %$l$%. Neither limitation applies to this implementation. |
167 | */ |
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168 | |
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169 | int dsa_gen(dsa_param *dp, unsigned ql, unsigned pl, unsigned steps, |
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170 | const void *k, size_t sz, dsa_seed *ds, |
171 | pgen_proc *event, void *ectx) |
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172 | { |
173 | dsa_stepctx s; |
174 | prim_ctx p; |
175 | int i; |
176 | rabin r; |
177 | mp *qc; |
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178 | |
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179 | /* --- Initialize the stepping context --- */ |
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180 | |
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181 | s.r = dsarand_create(k, sz); |
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182 | |
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183 | /* --- Find @q@ --- */ |
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184 | |
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185 | s.q = 0; |
186 | s.r->ops->misc(s.r, DSARAND_PASSES, 2); |
187 | s.bits = ql; |
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188 | s.count = 0; |
189 | s.or = 1; |
190 | if (!ds) |
191 | s.seedbuf = 0; |
192 | else { |
193 | ds->sz = sz; |
194 | ds->p = s.seedbuf = xmalloc(sz); |
195 | } |
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196 | if ((dp->q = pgen("q", MP_NEW, MP_NEW, event, ectx, steps, dsa_step, &s, |
197 | rabin_iters(ql), pgen_test, &r)) == 0) |
198 | goto fail_q; |
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199 | |
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200 | /* --- Find @p@ --- */ |
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201 | |
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202 | s.count = ~0; |
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203 | s.q = mp_lsl(MP_NEW, dp->q, 1); |
204 | s.r->ops->misc(s.r, DSARAND_PASSES, 1); |
205 | s.bits = pl; |
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206 | s.seedbuf = 0; |
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207 | if ((dp->p = pgen("p", MP_NEW, MP_NEW, event, ectx, 4096, dsa_step, &s, |
208 | rabin_iters(pl), pgen_test, &r)) == 0) |
209 | goto fail_p; |
210 | mp_drop(s.q); |
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211 | if (ds) |
212 | ds->count = s.count; |
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213 | |
214 | /* --- Find @g@ --- * |
215 | * |
216 | * The division returns remainder 1. This doesn't matter. |
217 | */ |
218 | |
219 | mpmont_create(&p.mm, dp->p); |
220 | qc = MP_NEW; mp_div(&qc, 0, dp->p, dp->q); |
221 | i = 0; |
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222 | p.exp = qc; |
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223 | p.n = 0; |
224 | if ((dp->g = pgen("g", MP_NEW, MP_NEW, event, ectx, 0, prim_step, &i, |
225 | 1, prim_test, &p)) == 0) |
226 | goto fail_g; |
227 | |
228 | /* --- Done --- */ |
229 | |
230 | mp_drop(qc); |
231 | mpmont_destroy(&p.mm); |
232 | s.r->ops->destroy(s.r); |
233 | return (PGEN_DONE); |
234 | |
235 | /* --- Tidy up when things go wrong --- */ |
236 | |
237 | fail_g: |
238 | mp_drop(qc); |
239 | mpmont_destroy(&p.mm); |
240 | fail_p: |
241 | mp_drop(dp->q); |
242 | mp_drop(s.q); |
243 | fail_q: |
244 | s.r->ops->destroy(s.r); |
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245 | if (ds) |
246 | xfree(ds->p); |
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247 | return (PGEN_ABORT); |
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248 | } |
249 | |
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250 | /*----- Test rig ----------------------------------------------------------*/ |
251 | |
252 | #ifdef TEST_RIG |
253 | |
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254 | static int verify(dstr *v) |
255 | { |
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256 | mp *q = *(mp **)v[4].buf; |
257 | mp *p = *(mp **)v[5].buf; |
258 | mp *g = *(mp **)v[6].buf; |
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259 | dsa_param dp; |
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260 | dsa_seed ds; |
261 | unsigned long l = *(unsigned long *)v[1].buf; |
262 | unsigned long n = *(unsigned long *)v[3].buf; |
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263 | int ok = 1; |
264 | int rc; |
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265 | keycheck kc; |
266 | keycheck_reportctx kcr; |
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267 | |
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268 | rc = dsa_gen(&dp, 160, l, 16, v[0].buf, v[0].len, &ds, pgen_evspin, 0); |
269 | if (rc || ds.count != n || ds.sz != v[2].len || |
270 | memcmp(ds.p, v[2].buf, v[2].len) != 0 || |
271 | !MP_EQ(q, dp.q) || !MP_EQ(p, dp.p) || !MP_EQ(g, dp.g)) { |
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272 | fputs("\n*** gen failed", stderr); |
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273 | fputs("\nseed_in = ", stderr); type_hex.dump(&v[0], stderr); |
274 | fprintf(stderr, "\nl = %lu", l); |
275 | fputs("\nseed_out = ", stderr); type_hex.dump(&v[2], stderr); |
276 | fprintf(stderr, "\ncount = %lu", n); |
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277 | fputs("\n q = ", stderr); mp_writefile(q, stderr, 16); |
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278 | fputs("\n p = ", stderr); mp_writefile(p, stderr, 16); |
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279 | fputs("\n g = ", stderr); mp_writefile(g, stderr, 16); |
280 | if (!rc) { |
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281 | dstr d; |
282 | d.buf = ds.p; d.len = ds.sz; |
283 | fputs("\nds.seed = ", stderr); type_hex.dump(&d, stderr); |
284 | fprintf(stderr, "\nds.count = %u", ds.count); |
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285 | fputs("\ndp.q = ", stderr); mp_writefile(dp.q, stderr, 16); |
286 | fputs("\ndp.p = ", stderr); mp_writefile(dp.p, stderr, 16); |
287 | fputs("\ndp.g = ", stderr); mp_writefile(dp.g, stderr, 16); |
288 | } |
289 | fputc('\n', stderr); |
290 | ok = 0; |
291 | } |
292 | |
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293 | kcr.fp = stderr; |
294 | kcr.sev = KCSEV_ERR; |
295 | keycheck_init(&kc, keycheck_stdreport, &kcr); |
296 | if (!rc) |
297 | dsa_checkparam(&kc, &dp, &ds); |
298 | if (!keycheck_allclear(&kc, KCSEV_ERR)) { |
299 | fputs("\n*** gen failed check", stderr); |
300 | fputs("\nseed_in = ", stderr); type_hex.dump(&v[0], stderr); |
301 | fprintf(stderr, "\nl = %lu", l); |
302 | fputs("\nseed_out = ", stderr); type_hex.dump(&v[2], stderr); |
303 | fprintf(stderr, "\ncount = %lu", n); |
304 | fputs("\n q = ", stderr); mp_writefile(q, stderr, 16); |
305 | fputs("\n p = ", stderr); mp_writefile(p, stderr, 16); |
306 | fputs("\n g = ", stderr); mp_writefile(g, stderr, 16); |
307 | fputc('\n', stderr); |
308 | ok = 0; |
309 | } |
310 | |
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311 | mp_drop(q); mp_drop(p); mp_drop(g); |
312 | if (!rc) { |
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313 | mp_drop(dp.q); mp_drop(dp.p); mp_drop(dp.g); xfree(ds.p); |
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314 | } |
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315 | assert(mparena_count(MPARENA_GLOBAL) == 0); |
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316 | return (ok); |
317 | } |
318 | |
319 | static test_chunk tests[] = { |
320 | { "gen", verify, |
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321 | { &type_hex, &type_ulong, &type_hex, &type_ulong, |
322 | &type_mp, &type_mp, &type_mp, 0 } }, |
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323 | { 0, 0, { 0 } } |
324 | }; |
325 | |
326 | int main(int argc, char *argv[]) |
327 | { |
328 | sub_init(); |
329 | test_run(argc, argv, tests, SRCDIR "/tests/dsa"); |
330 | return (0); |
331 | } |
332 | |
333 | #endif |
334 | |
335 | /*----- That's all, folks -------------------------------------------------*/ |