/* -*-c-*-
*
- * $Id: cc-kem.c,v 1.1 2004/04/17 09:58:37 mdw Exp $
+ * $Id$
*
* Catcrypt key-encapsulation
*
ge *y;
} dh_encctx;
-static dh_encctx *dh_doinit(key *k, const gprime_param *gp, mp *y)
+static dh_encctx *dh_doinit(key *k, const gprime_param *gp, mp *y,
+ group *(*makegroup)(const gprime_param *),
+ const char *what)
{
dh_encctx *de = CREATE(dh_encctx);
dstr t = DSTR_INIT;
key_fulltag(k, &t);
- if ((de->g = group_prime(gp)) == 0)
- die(EXIT_FAILURE, "bad prime group in key `%s'", t.buf);
+ if ((de->g = makegroup(gp)) == 0)
+ die(EXIT_FAILURE, "bad %s group in key `%s'", what, t.buf);
de->x = MP_NEW;
de->y = G_CREATE(de->g);
if (G_FROMINT(de->g, de->y, y))
static kem *dh_encinit(key *k, void *kd)
{
dh_pub *dp = kd;
- dh_encctx *de = dh_doinit(k, &dp->dp, dp->y);
+ dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_prime, "prime");
+ return (&de->k);
+}
+
+static kem *bindh_encinit(key *k, void *kd)
+{
+ dh_pub *dp = kd;
+ dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_binary, "binary");
return (&de->k);
}
G_DESTROY(de->g, de->y);
mp_drop(de->x);
G_DESTROYGROUP(de->g);
+ DESTROY(de);
}
static const kemops dh_encops = {
dh_encinit, dh_encdoit, dh_enccheck, dh_encdestroy
};
+static const kemops bindh_encops = {
+ dh_pubfetch, sizeof(dh_pub),
+ bindh_encinit, dh_encdoit, dh_enccheck, dh_encdestroy
+};
+
static const kemops ec_encops = {
ec_pubfetch, sizeof(ec_pub),
ec_encinit, dh_encdoit, dh_enccheck, dh_encdestroy
static kem *dh_decinit(key *k, void *kd)
{
dh_priv *dp = kd;
- dh_encctx *de = dh_doinit(k, &dp->dp, dp->y);
+ dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_prime, "prime");
+ de->x = MP_COPY(dp->x);
+ return (&de->k);
+}
+
+static kem *bindh_decinit(key *k, void *kd)
+{
+ dh_priv *dp = kd;
+ dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_binary, "binary");
de->x = MP_COPY(dp->x);
return (&de->k);
}
dh_decinit, dh_decdoit, dh_enccheck, dh_encdestroy
};
+static const kemops bindh_decops = {
+ dh_privfetch, sizeof(dh_priv),
+ bindh_decinit, dh_decdoit, dh_enccheck, dh_encdestroy
+};
+
static const kemops ec_decops = {
ec_privfetch, sizeof(ec_priv),
ec_decinit, dh_decdoit, dh_enccheck, dh_encdestroy
};
+/* --- Symmetric --- */
+
+typedef struct symm_ctx {
+ kem k;
+ key_packdef kp;
+ key_bin kb;
+} symm_ctx;
+
+static kem *symm_init(key *k, void *kd)
+{
+ symm_ctx *s;
+ dstr d = DSTR_INIT;
+ int err;
+
+ s = CREATE(symm_ctx);
+
+ key_fulltag(k, &d);
+ s->kp.e = KENC_BINARY;
+ s->kp.p = &s->kb;
+ s->kp.kd = 0;
+
+ if ((err = key_unpack(&s->kp, kd, &d)) != 0) {
+ die(EXIT_FAILURE, "failed to unpack symmetric key `%s': %s",
+ d.buf, key_strerror(err));
+ }
+ dstr_destroy(&d);
+ return (&s->k);
+}
+
+static int symm_decdoit(kem *k, dstr *d, ghash *h)
+{
+ symm_ctx *s = (symm_ctx *)k;
+
+ GH_HASH(h, s->kb.k, s->kb.sz);
+ GH_HASH(h, d->buf, d->len);
+ return (0);
+}
+
+static int symm_encdoit(kem *k, dstr *d, ghash *h)
+{
+ dstr_ensure(d, h->ops->c->hashsz);
+ d->len += h->ops->c->hashsz;
+ rand_get(RAND_GLOBAL, d->buf, d->len);
+ return (symm_decdoit(k, d, h));
+}
+
+static const char *symm_check(kem *k) { return (0); }
+
+static void symm_destroy(kem *k)
+ { symm_ctx *s = (symm_ctx *)k; key_unpackdone(&s->kp); }
+
+static const kemops symm_encops = {
+ 0, 0,
+ symm_init, symm_encdoit, symm_check, symm_destroy
+};
+
+static const kemops symm_decops = {
+ 0, 0,
+ symm_init, symm_decdoit, symm_check, symm_destroy
+};
+
/* --- The switch table --- */
-static const struct kemtab {
- const char *name;
- const kemops *encops;
- const kemops *decops;
-} kemtab[] = {
+const struct kemtab kemtab[] = {
{ "rsa", &rsa_encops, &rsa_decops },
{ "dh", &dh_encops, &dh_decops },
+ { "bindh", &bindh_encops, &bindh_decops },
{ "ec", &ec_encops, &ec_decops },
+ { "symm", &symm_encops, &symm_decops },
{ 0, 0, 0 }
};
kalg, t.buf);
k_found:;
ko = wantpriv ? kt->decops : kt->encops;
- kd = xmalloc(ko->kdsz);
- kp = key_fetchinit(ko->kf, 0, kd);
- if ((e = key_fetch(kp, k)) != 0)
- die(EXIT_FAILURE, "error fetching key `%s': %s", t.buf, key_strerror(e));
+ if (!ko->kf) {
+ kd = k->k;
+ key_incref(kd);
+ } else {
+ kd = xmalloc(ko->kdsz);
+ kp = key_fetchinit(ko->kf, 0, kd);
+ if ((e = key_fetch(kp, k)) != 0) {
+ die(EXIT_FAILURE, "error fetching key `%s': %s",
+ t.buf, key_strerror(e));
+ }
+ }
kk = ko->init(k, kd);
kk->kp = kp;
kk->ops = ko;
octet *kd;
size_t n, cn, mn;
ghash *h;
- int rc = 0;
+ int rc = -1;
h = GH_INIT(k->h);
if (k->ops->doit(k, d, h))
void freekem(kem *k)
{
- key_fetchdone(k->kp);
- xfree(k->kd);
+ if (!k->ops->kf)
+ key_drop(k->kd);
+ else {
+ key_fetchdone(k->kp);
+ xfree(k->kd);
+ }
k->ops->destroy(k);
}