+++ /dev/null
-/* -*-c-*-
- *
- * $Id$
- *
- * Generalized version of DSA
- *
- * (c) 2004 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of Catacomb.
- *
- * Catacomb is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * Catacomb is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with Catacomb; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include "dsa.h"
-#include "gdsa.h"
-#include "group.h"
-#include "ghash.h"
-#include "mpbarrett.h"
-#include "mprand.h"
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- @gdsa_beginhash@ --- *
- *
- * Arguments: @const gdsa *c@ = pointer to the context structure
- *
- * Returns: A hashing context for you to hash the message.
- *
- * Use: Initializes a hash function correctly for you to hash a
- * message. Requires @h@.
- */
-
-ghash *gdsa_beginhash(const gdsa *c) { return (GH_INIT(c->h)); }
-
-/* --- @gdsa_endhash@ --- *
- *
- * Arguments: @const gdsa *c@ = pointer to the context structure
- * @ghash *h@ = the hashing context
- *
- * Returns: ---
- *
- * Use: Does any final thing that DSA wants to do when hashing a
- * message. (Actually, there's nothing.) The hashing context
- * isn't finalized.
- */
-
-void gdsa_endhash(const gdsa *c, ghash *h) { ; }
-
-/* --- @gdsa_sign@ --- *
- *
- * Arguments: @const gdsa *c@ = my context structure
- * @gdsa_sig *s@ = where to put the signature (initialized)
- * @const void *m@ = pointer to message hash
- * @mp *k@ = random exponent for this message or null
- *
- * Returns: ---
- *
- * Use: Signs a message. Requires @g@, @u@, @h@, and @r@ if @k@ is
- * null. This is a better idea than inventing @k@ yourself.
- */
-
-void gdsa_sign(const gdsa *c, gdsa_sig *s, const void *m, mp *k)
-{
- group *g = c->g;
- mp *mr = dsa_h2n(MP_NEW, g->r, m, c->h->hashsz);
- ge *z = G_CREATE(g);
- mp *sr = s->r, *ss = s->s;
- mpbarrett b;
-
- if (k) { MP_COPY(k); goto have_k; }
-new_k:
- k = mprand_range(k, g->r, c->r, 0);
-have_k:
- if (MP_ZEROP(k)) goto new_k;
- G_EXP(g, z, g->g, k);
- sr = G_TOINT(g, sr, z); assert(sr);
- if (MP_ZEROP(sr)) goto new_k;
-
- mp_div(0, &sr, sr, g->r);
- mpbarrett_create(&b, g->r);
- ss = mp_mul(ss, sr, c->u); ss = mpbarrett_reduce(&b, ss, ss);
- ss = mp_add(ss, ss, mr); mp_div(0, &ss, ss, g->r);
- k = mp_modinv(k, k, g->r);
- ss = mp_mul(ss, ss, k); ss = mpbarrett_reduce(&b, ss, ss);
- s->r = sr; s->s = ss;
- mp_drop(k); mp_drop(mr); mpbarrett_destroy(&b); G_DESTROY(g, z);
-}
-
-/* --- @gdsa_verify@ --- *
- *
- * Arguments: @const gdsa *c@ = my context structure
- * @const gdsa_sig *s@ = the signature to verify
- * @const void *m@ = pointer to message hash
- *
- * Returns: Zero if OK, negative on failure.
- *
- * Use: Checks a signature on a message, Requires @g@, @p@ and @h@.
- */
-
-int gdsa_verify(const gdsa *c, const gdsa_sig *s, const void *m)
-{
- group *g = c->g;
- group_expfactor e[2];
- mpbarrett b;
- mp *h, *t;
- ge *w;
- int rc = -1;
-
- if (MP_CMP(s->r, <, MP_ONE) || MP_CMP(s->r, >=, g->r) ||
- MP_CMP(s->s, <, MP_ONE) || MP_CMP(s->s, >=, g->r))
- return (-1);
- mpbarrett_create(&b, g->r); h = mp_modinv(MP_NEW, s->s, g->r);
- e[0].base = g->g; e[1].base = c->p;
- t = dsa_h2n(MP_NEW, g->r, m, c->h->hashsz); mp_div(0, &t, t, g->r);
- t = mp_mul(t, t, h); e[0].exp = t = mpbarrett_reduce(&b, t, t);
- h = mp_mul(h, s->r, h); e[1].exp = h = mpbarrett_reduce(&b, h, h);
- w = G_CREATE(g); G_MEXP(g, w, e, 2);
- t = G_TOINT(g, t, w); if (!t) goto done;
- mp_div(0, &t, t, g->r); if (MP_EQ(t, s->r)) rc = 0;
-done:
- G_DESTROY(g, w); mp_drop(t); mp_drop(h); mpbarrett_destroy(&b);
- return (rc);
-}
-
-/*----- Test rig ----------------------------------------------------------*/
-
-#ifdef TEST_RIG
-
-static group *getgroup(const char *p) {
- group *g; qd_parse qd;
- qd.p = p; qd.e = 0; g = group_parse(&qd);
- if (g && !qd_eofp(&qd)) { G_DESTROYGROUP(g); g = 0; qd.e = "junk at eof"; }
- if (!g) { fprintf(stderr, "bad group string `%.*s|%s': %s\n", qd.p - p,
- p, qd.p, qd.e); exit(1); }
- return (g);
-}
-
-static ge *getge(group *g, const char *p) {
- ge *x = G_CREATE(g);
- if (group_readstring(g, x, p, 0)) {
- fprintf(stderr, "bad group element `%s'\n", p);
- exit(1);
- }
- return (x);
-}
-
-static void showge(group *g, const char *p, ge *x) {
- fprintf(stderr, "*** %s = ", p); group_writefile(g, x, stderr);
- putc('\n', stderr);
-}
-
-static void showmp(const char *p, mp *x, int r) {
- fprintf(stderr, "*** %s = ", p); mp_writefile(x, stderr, r);
- putc('\n', stderr);
-}
-
-static int tsign(dstr *v)
-{
- gdsa c;
- gdsa_sig s, ss = GDSA_SIG_INIT;
- ghash *h;
- mp *k;
- int ok = 1;
-
- c.g = getgroup(v[0].buf); c.h = ghash_byname(v[1].buf);
- c.u = *(mp **)v[2].buf; k = *(mp **)v[4].buf;
- s.r = *(mp **)v[5].buf; s.s = *(mp **)v[6].buf;
-
- h = gdsa_beginhash(&c);
- GH_HASH(h, v[3].buf, v[3].len);
- gdsa_endhash(&c, h);
- gdsa_sign(&c, &ss, GH_DONE(h, 0), k);
- if (!MP_EQ(s.r, ss.r) || !MP_EQ(s.s, ss.s)) {
- ok = 0;
- fprintf(stderr, "*** sign failed!\n");
- fprintf(stderr, "*** group: %s\n", v[0].buf);
- fprintf(stderr, "*** hash: %s\n", c.h->name);
- showmp("private key", c.u, 16);
- fprintf(stderr, "*** message: `%s'\n", v[3].buf);
- showmp("computed r", ss.r, 16); showmp("computed s", ss.s, 16);
- showmp("expected r", s.r, 16); showmp("expected s", s.s, 16);
- }
- mp_drop(s.r); mp_drop(s.s); mp_drop(ss.r); mp_drop(ss.s);
- mp_drop(k); mp_drop(c.u); G_DESTROYGROUP(c.g); GH_DESTROY(h);
- assert(mparena_count(MPARENA_GLOBAL) == 0);
- return (ok);
-}
-
-static int tverify(dstr *v)
-{
- gdsa c;
- gdsa_sig s;
- ghash *h;
- int rc, erc;
- int ok = 1;
-
- c.g = getgroup(v[0].buf); c.h = ghash_byname(v[1].buf);
- c.p = getge(c.g, v[2].buf);
- s.r = *(mp **)v[4].buf; s.s = *(mp **)v[5].buf;
- erc = *(int *)v[6].buf;
-
- h = gdsa_beginhash(&c);
- GH_HASH(h, v[3].buf, v[3].len);
- gdsa_endhash(&c, h);
- rc = gdsa_verify(&c, &s, GH_DONE(h, 0));
- if (!rc != !erc) {
- ok = 0;
- fprintf(stderr, "*** verify failed!\n");
- fprintf(stderr, "*** group: %s\n", v[0].buf);
- fprintf(stderr, "*** hash: %s\n", c.h->name);
- showge(c.g, "public key", c.p);
- fprintf(stderr, "*** message: `%s'\n", v[3].buf);
- showmp("sig r", s.r, 16); showmp("sig s", s.s, 16);
- fprintf(stderr, "*** expected %s\n", !erc ? "pass" : "fail");
- }
- mp_drop(s.r); mp_drop(s.s); G_DESTROY(c.g, c.p); G_DESTROYGROUP(c.g);
- GH_DESTROY(h);
- assert(mparena_count(MPARENA_GLOBAL) == 0);
- return (ok);
-}
-
-static const test_chunk tests[] = {
- { "sign", tsign, { &type_string, &type_string, &type_mp, &type_string,
- &type_mp, &type_mp, &type_mp } },
- { "verify", tverify, { &type_string, &type_string, &type_string,
- &type_string, &type_mp, &type_mp, &type_int } },
- { 0 }
-};
-
-int main(int argc, char *argv[])
-{
- sub_init();
- test_run(argc, argv, tests, SRCDIR "/tests/gdsa");
- return (0);
-}
-
-#endif
-
-/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff