X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/2b645fb792c62ae0d38fcde4c39e1bd0889b0e06..dbfee00a86609283c4633df870692be3db9bc5e4:/ec.c

diff --git a/ec.c b/ec.c
index 47c01a9..4111928 100644
--- a/ec.c
+++ b/ec.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: ec.c,v 1.4 2003/05/15 23:25:59 mdw Exp $
+ * $Id: ec.c,v 1.4.4.1 2003/06/10 13:43:53 mdw Exp $
  *
  * Elliptic curve definitions
  *
@@ -30,6 +30,9 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: ec.c,v $
+ * Revision 1.4.4.1  2003/06/10 13:43:53  mdw
+ * Simple (non-projective) curves over prime fields now seem to work.
+ *
  * Revision 1.4  2003/05/15 23:25:59  mdw
  * Make elliptic curve stuff build.
  *
@@ -250,6 +253,24 @@ ec *ec_find(ec_curve *c, ec *d, mp *x)
   return (d);
 }
 
+/* --- @ec_neg@ --- *
+ *
+ * Arguments:	@ec_curve *c@ = pointer to an elliptic curve
+ *		@ec *d@ = pointer to the destination point
+ *		@const ec *p@ = pointer to the operand point
+ *
+ * Returns:	The destination point.
+ *
+ * Use:		Computes the negation of the given point.
+ */
+
+ec *ec_neg(ec_curve *c, ec *d, const ec *p)
+{
+  EC_IN(c, d, p);
+  EC_NEG(c, d, d);
+  return (EC_OUT(c, d, d));
+}
+
 /* --- @ec_add@ --- *
  *
  * Arguments:	@ec_curve *c@ = pointer to an elliptic curve
@@ -273,6 +294,29 @@ ec *ec_add(ec_curve *c, ec *d, const ec *p, const ec *q)
   return (d);
 }
 
+/* --- @ec_sub@ --- *
+ *
+ * Arguments:	@ec_curve *c@ = pointer to an elliptic curve
+ *		@ec *d@ = pointer to the destination point
+ *		@const ec *p, *q@ = pointers to the operand points
+ *
+ * Returns:	The destination @d@.
+ *
+ * Use:		Subtracts one point from another on an elliptic curve.
+ */
+
+ec *ec_sub(ec_curve *c, ec *d, const ec *p, const ec *q)
+{
+  ec pp, qq;
+  EC_IN(c, &pp, p);
+  EC_IN(c, &qq, q);
+  EC_SUB(c, d, &qq, &qq);
+  EC_OUT(c, d, d);
+  EC_DESTROY(&pp);
+  EC_DESTROY(&qq);
+  return (d);
+}
+
 /* --- @ec_dbl@ --- *
  *
  * Arguments:	@ec_curve *c@ = pointer to an elliptic curve
@@ -320,6 +364,7 @@ ec *ec_imul(ec_curve *c, ec *d, const ec *p, mp *n)
     EXP_SIMPLE(*d, t, n);
   else
     EXP_WINDOW(*d, t, n);
+  EC_DESTROY(&t);
   return (d);
 }