X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/b817bfc642225b8c3c0b6a7e42d1fb949b61a606..78614e02310dbe879d55f0a68e47349db074ff61:/ec-prime.c

diff --git a/ec-prime.c b/ec-prime.c
index 8f3c731..52815e4 100644
--- a/ec-prime.c
+++ b/ec-prime.c
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: ec-prime.c,v 1.11 2004/04/08 01:36:15 mdw Exp $
+ * $Id$
  *
  * Elliptic curves over prime fields
  *
  * (c) 2001 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of Catacomb.
  *
@@ -15,12 +15,12 @@
  * 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,
@@ -68,10 +68,8 @@ static ec *ecfind(ec_curve *c, ec *d, mp *x)
 
 static ec *ecdbl(ec_curve *c, ec *d, const ec *a)
 {
-  if (EC_ATINF(a))
+  if (EC_ATINF(a) || F_ZEROP(c->f, a->y))
     EC_SETINF(d);
-  else if (F_ZEROP(c->f, a->y))
-    EC_COPY(d, a);
   else {
     field *f = c->f;
     mp *lambda;
@@ -102,10 +100,8 @@ static ec *ecdbl(ec_curve *c, ec *d, const ec *a)
 
 static ec *ecprojdbl(ec_curve *c, ec *d, const ec *a)
 {
-  if (EC_ATINF(a))
+  if (EC_ATINF(a) || F_ZEROP(c->f, a->y))
     EC_SETINF(d);
-  else if (F_ZEROP(c->f, a->y))
-    EC_COPY(d, a);
   else {
     field *f = c->f;
     mp *p, *q, *m, *s, *dx, *dy, *dz;
@@ -146,10 +142,8 @@ static ec *ecprojdbl(ec_curve *c, ec *d, const ec *a)
 
 static ec *ecprojxdbl(ec_curve *c, ec *d, const ec *a)
 {
-  if (EC_ATINF(a))
+  if (EC_ATINF(a) || F_ZEROP(c->f, a->y))
     EC_SETINF(d);
-  else if (F_ZEROP(c->f, a->y))
-    EC_COPY(d, a);
   else {
     field *f = c->f;
     mp *p, *q, *m, *s, *dx, *dy, *dz;
@@ -284,7 +278,7 @@ static ec *ecprojadd(ec_curve *c, ec *d, const ec *a, const ec *b)
     q = F_MUL(f, MP_NEW, p, u);		/* %$t w^2$% */
     u = F_MUL(f, u, p, w);		/* %$w^3$% */
     p = F_MUL(f, p, u, s);		/* %$m w^3$% */
-    
+
     dx = F_SQR(f, u, r);		/* %$r^2$% */
     dx = F_SUB(f, dx, dx, q);		/* %$x' = r^2 - t w^2$% */
 
@@ -329,7 +323,7 @@ static int ecprojcheck(ec_curve *c, const ec *p)
 {
   ec t = EC_INIT;
   int rc;
-  
+
   c->ops->fix(c, &t, p);
   rc = eccheck(c, &t);
   EC_DESTROY(&t);
@@ -384,16 +378,19 @@ extern ec_curve *ec_primeproj(field *f, mp *a, mp *b)
 }
 
 static const ec_ops ec_primeops = {
+  "prime",
   ecdestroy, ec_stdsamep, ec_idin, ec_idout, ec_idfix,
   ecfind, ecneg, ecadd, ec_stdsub, ecdbl, eccheck
 };
 
 static const ec_ops ec_primeprojops = {
+  "primeproj",
   ecdestroy, ec_stdsamep, ec_projin, ec_projout, ec_projfix,
   ecfind, ecneg, ecprojadd, ec_stdsub, ecprojdbl, ecprojcheck
 };
 
 static const ec_ops ec_primeprojxops = {
+  "primeproj",
   ecdestroy, ec_stdsamep, ec_projin, ec_projout, ec_projfix,
   ecfind, ecneg, ecprojadd, ec_stdsub, ecprojxdbl, ecprojcheck
 };
@@ -421,11 +418,11 @@ int main(int argc, char *argv[])
 
   f = field_niceprime(p);
   c = ec_primeproj(f, a, b);
-  
+
   g.x = MP(0xaa87ca22be8b05378eb1c71ef320ad746e1d3b628ba79b9859f741e082542a385502f25dbf55296c3a545e3872760ab7);
   g.y = MP(0x3617de4a96262c6f5d9e98bf9292dc29f8f41dbd289a147ce9da3113b5f0b8c00a60b1ce1d7e819d7a431d7c90ea0e5f);
 
-  for (i = 0; i < n; i++) { 
+  for (i = 0; i < n; i++) {
     ec_mul(c, &d, &g, r);
     if (EC_ATINF(&d)) {
       fprintf(stderr, "zero too early\n");