Add cyclic group abstraction, with test code. Separate off exponentation

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

diff --git a/f-prime.c b/f-prime.c
index 7215ec8..473ba4c 100644 (file)
--- a/f-prime.c
+++ b/f-prime.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: f-prime.c,v 1.3.4.3 2004/03/21 22:39:46 mdw Exp $
+ * $Id: f-prime.c,v 1.8 2004/04/01 12:50:09 mdw Exp $
  *
  * Prime fields with Montgomery arithmetic
  *
@@ -30,6 +30,25 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: f-prime.c,v $
+ * Revision 1.8  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 1.7  2004/03/27 17:54:11  mdw
+ * Standard curves and curve checking.
+ *
+ * Revision 1.6  2004/03/23 15:19:32  mdw
+ * Test elliptic curves more thoroughly.
+ *
+ * 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.
+ *
  * Revision 1.3.4.3  2004/03/21 22:39:46  mdw
  * Elliptic curves on binary fields work.
  *
@@ -56,6 +75,7 @@
 
 #include "field.h"
 #include "mpmont.h"
+#include "mprand.h"
 
 /*----- Data structures ---------------------------------------------------*/
 
@@ -75,6 +95,12 @@ 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;
@@ -205,7 +231,8 @@ static mp *fhlv(field *ff, mp *d, mp *x)
 /* --- Field operations table --- */
 
 static field_ops fops = {
-  fdestroy,
+  FTY_PRIME, "prime",
+  fdestroy, frand, field_stdsamep,
   fin, fout,
   fzerop, fneg, fadd, fsub, fmul, fsqr, finv, freduce, fsqrt,
   0,
@@ -229,6 +256,9 @@ field *field_prime(mp *p)
   mpmont_create(&f->mm, p);
   f->f.zero = MP_ZERO;
   f->f.one = f->mm.r;
+  f->f.m = f->mm.m;
+  f->f.nbits = mp_bits(p);
+  f->f.noctets = (f->f.nbits + 7) >> 3;
   return (&f->f);
 }