New function and example program computes Fibonacci numbers fairly fast.

[u/mdw/catacomb] / dsa-verify.c

diff --git a/dsa-verify.c b/dsa-verify.c
index fee0dd3..90895b4 100644 (file)
--- a/dsa-verify.c
+++ b/dsa-verify.c
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: dsa-verify.c,v 1.3 1999/12/10 23:18:38 mdw Exp $
+ * $Id: dsa-verify.c,v 1.7 2004/04/08 01:36:15 mdw Exp $
  *
  * DSA signature verification
  *
  * (c) 1999 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of Catacomb.
  *
@@ -15,32 +15,18 @@
  * 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.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: dsa-verify.c,v $
- * Revision 1.3  1999/12/10 23:18:38  mdw
- * Change interface for suggested destinations.
- *
- * Revision 1.2  1999/11/23 00:20:04  mdw
- * Remove stray debugging code.
- *
- * Revision 1.1  1999/11/19 19:28:00  mdw
- * Implementation of the Digital Signature Algorithm.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include "dsa.h"
@@ -65,7 +51,7 @@ int dsa_vrfy(const dsa_param *dp, mp *y, mp *m, mp *r, mp *s)
 {
   mpmont pm, qm;
   mp *w;
-  mpmont_factor f[2];
+  mp_expfactor f[2];
   int ok;
 
   /* --- Ensure that all of the signature bits are in range --- */
@@ -83,13 +69,12 @@ int dsa_vrfy(const dsa_param *dp, mp *y, mp *m, mp *r, mp *s)
   /* --- Compute %$w = s^{-1} \bmod q$% --- */
 
   {
-    mp *z = MP_NEW;
-    mp_gcd(0, 0, &z, dp->q, s);
+    mp *z = mp_modinv(MP_NEW, s, dp->q);
     w = mpmont_mul(&qm, MP_NEW, z, qm.r2);
     mp_drop(z);
   }
 
-  /* --- Compute %$wr%$ and %$wm$% --- */
+  /* --- Compute %$wr$% and %$wm$% --- */
 
   f[0].exp = mpmont_mul(&qm, MP_NEW, w, m);
   f[1].exp = mpmont_mul(&qm, MP_NEW, w, r);
@@ -102,7 +87,7 @@ int dsa_vrfy(const dsa_param *dp, mp *y, mp *m, mp *r, mp *s)
   f[1].base = y;
   w = mpmont_mexp(&pm, MP_NEW, f, 2);
   mp_div(0, &w, w, dp->q);
-  ok = MP_CMP(w, ==, r);
+  ok = MP_EQ(w, r);
 
   /* --- Tidy up --- */
 
@@ -134,7 +119,7 @@ int dsa_verify(const dsa_param *dp, mp *y,
               const void *r, size_t rsz,
               const void *s, size_t ssz)
 {
-  mp *mm = mp_loadb(MP_NEW, m, msz);
+  mp *mm = dsa_h2n(MP_NEW, dp->q, m, msz);
   mp *rm = mp_loadb(MP_NEW, r, rsz);
   mp *sm = mp_loadb(MP_NEW, s, ssz);
   int ok = dsa_vrfy(dp, y, mm, rm, sm);