X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/a2a74efe4b1276b1efec12f25fd65f0df060f38a..80be023065ced106a4078a36371c135a60d2bd6c:/calc/ecp.cal

diff --git a/calc/ecp.cal b/calc/ecp.cal
index 04971aa..0163d5e 100644
--- a/calc/ecp.cal
+++ b/calc/ecp.cal
@@ -1,6 +1,6 @@
 /* -*-apcalc-*-
  *
- * $Id: ecp.cal,v 1.1 2000/10/08 16:01:37 mdw Exp $
+ * $Id: ecp.cal,v 1.5 2004/04/08 01:36:15 mdw Exp $
  *
  * Testbed for elliptic curve arithmetic over prime fields
  *
@@ -27,14 +27,6 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: ecp.cal,v $
- * Revision 1.1  2000/10/08 16:01:37  mdw
- * Prototypes of various bits of code.
- *
- */
-
 /*----- Object types ------------------------------------------------------*/
 
 obj ecp_curve { a, b, p };
@@ -96,15 +88,38 @@ define ecp_pt_add(a, b)
   return (d);
 }
 
+define ecp_pt_dbl(a)
+{
+  local e, alpha;
+  local obj ecp_pt d;
+  if (istype(a, 1))
+    return (0);
+  e = a.e;
+  alpha = (3 * a.x^2 + e.a) * minv(2 * a.y, e.p) % e.p;
+  d.x = (alpha^2 - 2 * a.x) % e.p;
+  d.y = (-a.y + alpha * (a.x - d.x)) % e.p;
+  d.e = e;
+  return (d);
+}
+
 define ecp_pt_neg(a)
 {
   local obj ecp_pt d;
   d.x = a.x;
-  d.y = -a.y;
+  d.y = a.e.p - a.y;
   d.e = a.e;
   return (d);
 }
 
+define ecp_pt_check(a)
+{
+  local e;
+
+  e = a.e;
+  if (a.y^2 % e.p != (a.x^3 + e.a * a.x + e.b) % e.p)
+    quit "bad curve point";
+}
+
 define ecp_pt_mul(a, b)
 {
   local p, n;
@@ -124,10 +139,18 @@ define ecp_pt_mul(a, b)
     if (n & 1)
       d += p;
     n >>= 1;
-    p += p;
+    p = ecp_pt_dbl(p);
   }
   return (d);
 }
 
+/*----- FIPS186-2 standard curves -----------------------------------------*/
+
+p192 = ecp_curve(-3, 0x64210519e59c80e70fa7e9ab72243049feb8deecc146b9b1,
+		 6277101735386680763835789423207666416083908700390324961279);
+p192_r = 6277101735386680763835789423176059013767194773182842284081;
+p192_g = ecp_pt(0x188da80eb03090f67cbf20eb43a18800f4ff0afd82ff1012,
+		0x07192b95ffc8da78631011ed6b24cdd573f977a11e794811, p192);
+
 /*----- That's all, folks -------------------------------------------------*/