X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/b085fd9162fa3ff5b16788ced6d11a71ffe5a5fe..6d56743beed37f62273209341fa812bcd6aa220f:/ec-prime.c

diff --git a/ec-prime.c b/ec-prime.c
index 09733ce..4611855 100644
--- a/ec-prime.c
+++ b/ec-prime.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: ec-prime.c,v 1.2 2002/01/13 13:48:44 mdw Exp $
+ * $Id: ec-prime.c,v 1.3 2003/05/15 23:25:59 mdw Exp $
  *
  * Elliptic curves over prime fields
  *
@@ -30,6 +30,9 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: ec-prime.c,v $
+ * Revision 1.3  2003/05/15 23:25:59  mdw
+ * Make elliptic curve stuff build.
+ *
  * Revision 1.2  2002/01/13 13:48:44  mdw
  * Further progress.
  *
@@ -40,6 +43,8 @@
 
 /*----- Header files ------------------------------------------------------*/
 
+#include <mLib/sub.h>
+
 #include "ec.h"
 
 /*----- Data structures ---------------------------------------------------*/
@@ -51,7 +56,9 @@ typedef struct ecctx {
 
 /*----- Main code ---------------------------------------------------------*/
 
-static ec *ecneg(ec_cuvrve *c, ec *d, const ec *p)
+static const ec_ops ec_primeops;
+
+static ec *ecneg(ec_curve *c, ec *d, const ec *p)
 {
   EC_COPY(d, p);
   d->y = F_NEG(c->f, d->y, d->y);
@@ -75,10 +82,10 @@ static ec *ecdbl(ec_curve *c, ec *d, const ec *a)
     dx = F_TPL(f, dx, dx);
     dx = F_ADD(f, dx, dx, cc->a);
     dy = F_INV(f, dy, dy);
-    lambda = F_MUL(d, MP_NEW, dx, dy);
+    lambda = F_MUL(f, MP_NEW, dx, dy);
 
     dx = F_SQR(f, dx, lambda);
-    dy = F_DBL(d, dy, a->x);
+    dy = F_DBL(f, dy, a->x);
     dx = F_SUB(f, dx, dx, dy);
     dy = F_SUB(f, dy, a->x, dx);
     dy = F_MUL(f, dy, lambda, dy);
@@ -121,7 +128,7 @@ static ec *ecadd(ec_curve *c, ec *d, const ec *a, const ec *b)
       dx = F_ADD(f, dx, dx, cc->a);
       dy = F_DBL(f, MP_NEW, a->y);
       dy = F_INV(f, dy, dy);
-      lambda = F_MUL(d, MP_NEW, dx, dy);
+      lambda = F_MUL(f, MP_NEW, dx, dy);
     }
 
     dx = F_SQR(f, dx, lambda);
@@ -140,4 +147,76 @@ static ec *ecadd(ec_curve *c, ec *d, const ec *a, const ec *b)
   return (d);
 }
 
+static void ecdestroy(ec_curve *c)
+{
+  ecctx *cc = (ecctx *)c;
+  MP_DROP(cc->a);
+  MP_DROP(cc->b);
+  DESTROY(cc);
+}
+
+/* --- @ec_prime@, @ec_primeproj@ --- *
+ *
+ * Arguments:	@field *f@ = the underyling field for this elliptic curve
+ *		@mp *a, *b@ = the coefficients for this curve
+ *
+ * Returns:	A pointer to the curve.
+ *
+ * Use:		Creates a curve structure for an elliptic curve defined over
+ *		a prime field.  The @primeproj@ variant uses projective
+ *		coordinates, which can be a win.
+ */
+
+extern ec_curve *ec_prime(field *f, mp *a, mp *b)
+{
+  ecctx *cc = CREATE(ecctx);
+  cc->c.ops = &ec_primeops;
+  cc->c.f = f;
+  cc->a = MP_COPY(a);
+  cc->b = MP_COPY(b);
+  return (&cc->c);
+}
+
+static const ec_ops ec_primeops = {
+  ecdestroy, ec_idin, ec_idout, 0, ecneg, ecadd, ec_stdsub, ecdbl
+};
+
+/*----- Test rig ----------------------------------------------------------*/
+
+#ifdef TEST_RIG
+
+#define MP(x) mp_readstring(MP_NEW, #x, 0, 0)
+
+int main(void)
+{
+  field *f;
+  ec_curve *c;
+  ec g = EC_INIT, d = EC_INIT;
+  mp *p, *a, *b, *r;
+
+  a = MP(-3);
+  b = MP(0x64210519e59c80e70fa7e9ab72243049feb8deecc146b9b1);
+  p = MP(6277101735386680763835789423207666416083908700390324961279);
+  r = MP(6277101735386680763835789423176059013767194773182842284081);
+
+  f = field_prime(p);
+  c = ec_prime(f, a, b);
+  
+  g.x = MP(0x188da80eb03090f67cbf20eb43a18800f4ff0afd82ff1012);
+  g.y = MP(0x07192b95ffc8da78631011ed6b24cdd573f977a11e794811);
+
+  ec_mul(c, &d, &g, r);
+  MP_PRINT("d.x", d.x);
+  MP_PRINT("d.y", d.y);
+
+  ec_destroy(&d);
+  ec_destroy(&g);
+  ec_destroycurve(c);
+  F_DESTROY(f);
+
+  return (0);
+}
+
+#endif
+
 /*----- That's all, folks -------------------------------------------------*/