/* -*-c-*-
*
- * $Id: dsa-sign.c,v 1.1 1999/11/19 19:28:00 mdw Exp $
+ * $Id: dsa-sign.c,v 1.3 2004/04/08 01:36:15 mdw Exp $
*
* DSA signing operation
*
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: dsa-sign.c,v $
- * Revision 1.1 1999/11/19 19:28:00 mdw
- * Implementation of the Digital Signature Algorithm.
- *
- */
-
/*----- Header files ------------------------------------------------------*/
#include "dsa.h"
#include "mp.h"
+#include "mpbarrett.h"
#include "mpmont.h"
/*----- Main code ---------------------------------------------------------*/
/* --- @dsa_mksig@ --- *
*
* Arguments: @const dsa_param *dp@ = pointer to DSA parameters
- * @const mp *a@ = secret signing key
- * @const mp *m@ = message to be signed
- * @const mp *k@ = random data
+ * @mp *a@ = secret signing key
+ * @mp *m@ = message to be signed
+ * @mp *k@ = random data
* @mp **rr, **ss@ = where to put output parameters
*
* Returns: ---
* Use: Computes a DSA signature of a message.
*/
-void dsa_mksig(const dsa_param *dp, const mp *a, const mp *m, const mp *k,
- mp **rr, mp **ss)
+void dsa_mksig(const dsa_param *dp, mp *a, mp *m, mp *k, mp **rr, mp **ss)
{
- mpmont pm, qm;
+ mpmont pm;
+ mpbarrett qb;
mp *k1, *r;
- mp *rrr, *ar;
-
- /* --- Create the Montgomery contexts --- */
-
- mpmont_create(&pm, dp->p);
- mpmont_create(&qm, dp->q);
+ mp *ar;
/* --- Compute %$r = (g^k \bmod p) \bmod q$% --- */
- r = mpmont_exp(&pm, dp->g, k);
+ mpmont_create(&pm, dp->p);
+ r = mpmont_exp(&pm, MP_NEW, dp->g, k);
+ mpmont_destroy(&pm);
mp_div(0, &r, r, dp->q);
- *rr = r;
/* --- Compute %$k^{-1} \bmod q$% --- */
- mp_gcd(0, 0, &k1, dp->q, (mp *)k);
+ k1 = mp_modinv(MP_NEW, k, dp->q);
/* --- Now for %$k^{-1}(m + ar)$% --- */
- rrr = mpmont_mul(&qm, MP_NEW, r, qm.r2);
- ar = mpmont_mul(&qm, MP_NEW, a, rrr);
+ mpbarrett_create(&qb, dp->q);
+ ar = mp_mul(MP_NEW, a, r);
ar = mp_add(ar, ar, m);
- if (MP_CMP(ar, >=, dp->q))
- ar = mp_sub(ar, ar, dp->q);
- rrr = mpmont_mul(&qm, rrr, ar, qm.r2);
- ar = mpmont_mul(&qm, ar, rrr, k1);
+ ar = mpbarrett_reduce(&qb, ar, ar);
+ ar = mp_mul(ar, ar, k1);
+ ar = mpbarrett_reduce(&qb, ar, ar);
+ mpbarrett_destroy(&qb);
+ MP_DROP(k1);
+ if (*rr) MP_DROP(*rr);
+ if (*ss) MP_DROP(*ss);
+ *rr = r;
*ss = ar;
-
- /* --- Tidy things up a little --- */
-
- mp_drop(rrr);
- mp_drop(k1);
- mpmont_destroy(&pm);
- mpmont_destroy(&qm);
}
/* --- @dsa_sign@ --- *
{
mp *mm = mp_loadb(MP_NEW, m, msz);
mp *km = mp_loadb(MP_NEW, k, ksz);
- mp *rm, *sm;
+ mp *rm = MP_NEW, *sm = MP_NEW;
dsa_mksig(dp, a, mm, km, &rm, &sm);
mp_storeb(rm, r, rsz);
mp_storeb(sm, s, ssz);
mp_drop(dp.q);
mp_drop(dp.g);
mp_drop(x);
+ assert(mparena_count(MPARENA_GLOBAL) == 0);
return (ok);
}