Random field-element selection.

[u/mdw/catacomb] / f-prime.c

diff --git a/f-prime.c b/f-prime.c
index 8454902..5ab4204 100644 (file)
--- a/f-prime.c
+++ b/f-prime.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: f-prime.c,v 1.4 2004/03/21 22:52:06 mdw Exp $
+ * $Id: f-prime.c,v 1.5 2004/03/23 12:08:26 mdw Exp $
  *
  * Prime fields with Montgomery arithmetic
  *
@@ -30,6 +30,9 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: f-prime.c,v $
+ * Revision 1.5  2004/03/23 12:08:26  mdw
+ * Random field-element selection.
+ *
  * Revision 1.4  2004/03/21 22:52:06  mdw
  * Merge and close elliptic curve branch.
  *
@@ -59,6 +62,7 @@
 
 #include "field.h"
 #include "mpmont.h"
+#include "mprand.h"
 
 /*----- Data structures ---------------------------------------------------*/
 
@@ -78,6 +82,12 @@ static void fdestroy(field *ff)
   DESTROY(f);
 }
 
+static mp *frand(field *ff, mp *d, grand *r)
+{
+  fctx *f = (fctx *)ff;
+  return (mprand_range(d, f->mm.m, r, 0));
+}
+
 static mp *fin(field *ff, mp *d, mp *x)
 {
   fctx *f = (fctx *)ff;
@@ -208,7 +218,7 @@ static mp *fhlv(field *ff, mp *d, mp *x)
 /* --- Field operations table --- */
 
 static field_ops fops = {
-  fdestroy,
+  fdestroy, frand,
   fin, fout,
   fzerop, fneg, fadd, fsub, fmul, fsqr, finv, freduce, fsqrt,
   0,