X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/c3caa2face1cda7002eb58245ad75865bf437455..1589affab225db500965e2cb869c534d6860e6bd:/f-binpoly.c

diff --git a/f-binpoly.c b/f-binpoly.c
index 02e683d..aeec0cf 100644
--- a/f-binpoly.c
+++ b/f-binpoly.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: f-binpoly.c,v 1.2 2004/03/21 22:52:06 mdw Exp $
+ * $Id: f-binpoly.c,v 1.6 2004/04/01 12:50:09 mdw Exp $
  *
  * Binary fields with polynomial basis representation
  *
@@ -30,6 +30,22 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: f-binpoly.c,v $
+ * Revision 1.6  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 1.5  2004/03/27 17:54:11  mdw
+ * Standard curves and curve checking.
+ *
+ * Revision 1.4  2004/03/23 15:19:32  mdw
+ * Test elliptic curves more thoroughly.
+ *
+ * Revision 1.3  2004/03/23 12:08:26  mdw
+ * Random field-element selection.
+ *
  * Revision 1.2  2004/03/21 22:52:06  mdw
  * Merge and close elliptic curve branch.
  *
@@ -45,6 +61,7 @@
 #include "field.h"
 #include "gf.h"
 #include "gfreduce.h"
+#include "mprand.h"
 
 /*----- Data structures ---------------------------------------------------*/
 
@@ -64,6 +81,11 @@ static void fdestroy(field *ff)
   DESTROY(f);
 }
 
+static mp *frand(field *f, mp *d, grand *r)
+{
+  return (mprand(d, f->nbits, r, 0));
+}
+
 static int fzerop(field *ff, mp *x)
 {
   return (!MP_LEN(x));
@@ -116,7 +138,8 @@ static mp *fquadsolve(field *ff, mp *d, mp *x)
 /* --- Field operations table --- */
 
 static field_ops fops = {
-  fdestroy,
+  FTY_BINARY, "binpoly",
+  fdestroy, frand, field_stdsamep,
   freduce, field_id,
   fzerop, field_id, fadd, fadd, fmul, fsqr, finv, freduce, fsqrt,
   fquadsolve,
@@ -138,7 +161,10 @@ field *field_binpoly(mp *p)
   f->f.ops = &fops;
   f->f.zero = MP_ZERO;
   f->f.one = MP_ONE;
+  f->f.nbits = mp_bits(p) - 1;
+  f->f.noctets = (f->f.nbits + 7) >> 3;
   gfreduce_create(&f->r, p);
+  f->f.m = f->r.p;
   return (&f->f);
 }