X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/432c4e184d44704511a5991b80224a87cb1d4613..02d7884df1f33c9c7dc3a14c4b1a5f520ebe090a:/ec-prime.c

diff --git a/ec-prime.c b/ec-prime.c
index ce81ba1..41ba9c4 100644
--- a/ec-prime.c
+++ b/ec-prime.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: ec-prime.c,v 1.8 2004/03/27 17:54:11 mdw Exp $
+ * $Id: ec-prime.c,v 1.10 2004/04/03 03:32:05 mdw Exp $
  *
  * Elliptic curves over prime fields
  *
@@ -30,6 +30,16 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: ec-prime.c,v $
+ * Revision 1.10  2004/04/03 03:32:05  mdw
+ * General robustification.
+ *
+ * Revision 1.9  2004/04/01 12:50:09  mdw
+ * Add cyclic group abstraction, with test code.  Separate off exponentation
+ * functions for better static linking.  Fix a buttload of bugs on the way.
+ * Generally ensure that negative exponents do inversion correctly.  Add
+ * table of standard prime-field subgroups.  (Binary field subgroups are
+ * currently unimplemented but easy to add if anyone ever finds a good one.)
+ *
  * Revision 1.8  2004/03/27 17:54:11  mdw
  * Standard curves and curve checking.
  *
@@ -349,10 +359,12 @@ static ec *ecprojadd(ec_curve *c, ec *d, const ec *a, const ec *b)
 static int eccheck(ec_curve *c, const ec *p)
 {
   field *f = c->f;
+  mp *l, *x, *r;
   int rc;
-  mp *l = F_SQR(f, MP_NEW, p->y);
-  mp *x = F_SQR(f, MP_NEW, p->x);
-  mp *r = F_MUL(f, MP_NEW, x, p->x);
+  if (EC_ATINF(p)) return (0);
+  l = F_SQR(f, MP_NEW, p->y);
+  x = F_SQR(f, MP_NEW, p->x);
+  r = F_MUL(f, MP_NEW, x, p->x);
   x = F_MUL(f, x, c->a, p->x);
   r = F_ADD(f, r, r, x);
   r = F_ADD(f, r, r, c->b);
@@ -386,7 +398,7 @@ static void ecdestroy(ec_curve *c)
  * Arguments:	@field *f@ = the underlying field for this elliptic curve
  *		@mp *a, *b@ = the coefficients for this curve
  *
- * Returns:	A pointer to the curve.
+ * Returns:	A pointer to the curve, or null.
  *
  * Use:		Creates a curve structure for an elliptic curve defined over
  *		a prime field.  The @primeproj@ variant uses projective
@@ -422,17 +434,17 @@ extern ec_curve *ec_primeproj(field *f, mp *a, mp *b)
 }
 
 static const ec_ops ec_primeops = {
-  ecdestroy, ec_idin, ec_idout, ec_idfix,
+  ecdestroy, ec_stdsamep, ec_idin, ec_idout, ec_idfix,
   ecfind, ecneg, ecadd, ec_stdsub, ecdbl, eccheck
 };
 
 static const ec_ops ec_primeprojops = {
-  ecdestroy, ec_projin, ec_projout, ec_projfix,
+  ecdestroy, ec_stdsamep, ec_projin, ec_projout, ec_projfix,
   ecfind, ecneg, ecprojadd, ec_stdsub, ecprojdbl, ecprojcheck
 };
 
 static const ec_ops ec_primeprojxops = {
-  ecdestroy, ec_projin, ec_projout, ec_projfix,
+  ecdestroy, ec_stdsamep, ec_projin, ec_projout, ec_projfix,
   ecfind, ecneg, ecprojadd, ec_stdsub, ecprojxdbl, ecprojcheck
 };