/* -*-c-*-
*
- * $Id: ec-bin.c,v 1.7 2004/04/01 21:28:41 mdw Exp $
+ * $Id$
*
* Arithmetic for elliptic curves over binary fields
*
* (c) 2004 Straylight/Edgeware
*/
-/*----- Licensing notice --------------------------------------------------*
+/*----- Licensing notice --------------------------------------------------*
*
* This file is part of Catacomb.
*
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
- *
+ *
* Catacomb is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
- *
+ *
* You should have received a copy of the GNU Library General Public
* License along with Catacomb; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: ec-bin.c,v $
- * Revision 1.7 2004/04/01 21:28:41 mdw
- * Normal basis support (translates to poly basis internally). Rewrite
- * EC and prime group table generators in awk, so that they can reuse data
- * for repeated constants.
- *
- * 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 2004/03/22 02:19:09 mdw
- * Rationalise the sliding-window threshold. Drop guarantee that right
- * arguments to EC @add@ are canonical, and fix up projective implementations
- * to cope.
- *
- * Revision 1.2 2004/03/21 22:52:06 mdw
- * Merge and close elliptic curve branch.
- *
- * Revision 1.1.2.1 2004/03/21 22:39:46 mdw
- * Elliptic curves on binary fields work.
- *
- */
-
/*----- Header files ------------------------------------------------------*/
#include <mLib/sub.h>
#include "ec.h"
-
-/*----- Data structures ---------------------------------------------------*/
-
-typedef struct ecctx {
- ec_curve c;
- mp *bb;
-} ecctx;
+#include "ec-guts.h"
/*----- Main code ---------------------------------------------------------*/
{
field *f = c->f;
mp *y, *u, *v;
-
+
if (F_ZEROP(f, x))
y = F_SQRT(f, MP_NEW, c->b);
else {
EC_SETINF(d);
else {
field *f = c->f;
- ecctx *cc = (ecctx *)c;
+ ecctx_bin *cc = (ecctx_bin *)c;
mp *dx, *dy, *dz, *u, *v;
dy = F_SQR(f, MP_NEW, a->z); /* %$z^2$% */
d->z = dz;
MP_DROP(u);
MP_DROP(v);
- assert(!(d->x->f & MP_DESTROYED));
- assert(!(d->y->f & MP_DESTROYED));
- assert(!(d->z->f & MP_DESTROYED));
}
return (d);
}
dx = F_ADD(f, dx, dx, c->a); /* %$a + \lambda^2 + \lambda$% */
dx = F_ADD(f, dx, dx, a->x); /* %$a + \lambda^2 + \lambda + x_0$% */
dx = F_ADD(f, dx, dx, b->x);
- /* %$x' = a + \lambda^2 + \lambda + x_0 + x_1$% */
+ /* %$x' = a + \lambda^2 + \lambda + x_0 + x_1$% */
} else if (!MP_EQ(a->y, b->y) || F_ZEROP(f, a->x)) {
EC_SETINF(d);
return (d);
dx = F_ADD(f, dx, dx, c->a); /* %$x' = a + \lambda^2 + \lambda$% */
dy = MP_NEW;
}
-
+
dy = F_ADD(f, dy, a->x, dx); /* %$ x + x' $% */
dy = F_MUL(f, dy, dy, lambda); /* %$ (x + x') \lambda$% */
dy = F_ADD(f, dy, dy, a->y); /* %$ (x + x') \lambda + y$% */
{
ec t = EC_INIT;
int rc;
-
+
c->ops->fix(c, &t, p);
rc = eccheck(c, &t);
EC_DESTROY(&t);
static void ecdestroy(ec_curve *c)
{
- ecctx *cc = (ecctx *)c;
+ ecctx_bin *cc = (ecctx_bin *)c;
MP_DROP(cc->c.a);
MP_DROP(cc->c.b);
if (cc->bb) MP_DROP(cc->bb);
* 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 binary field. The @binproj@ variant uses projective
ec_curve *ec_bin(field *f, mp *a, mp *b)
{
- ecctx *cc = CREATE(ecctx);
+ ecctx_bin *cc = CREATE(ecctx_bin);
cc->c.ops = &ec_binops;
cc->c.f = f;
cc->c.a = F_IN(f, MP_NEW, a);
ec_curve *ec_binproj(field *f, mp *a, mp *b)
{
- ecctx *cc = CREATE(ecctx);
+ ecctx_bin *cc = CREATE(ecctx_bin);
+ int i;
+ mp *c, *d;
+
cc->c.ops = &ec_binprojops;
cc->c.f = f;
cc->c.a = F_IN(f, MP_NEW, a);
cc->c.b = F_IN(f, MP_NEW, b);
- cc->bb = F_SQRT(f, MP_NEW, cc->c.b);
- cc->bb = F_SQRT(f, cc->bb, cc->bb);
+
+ c = MP_COPY(cc->c.b);
+ for (i = 0; i < f->nbits - 2; i++)
+ c = F_SQR(f, c, c);
+ d = F_SQR(f, MP_NEW, c); d = F_SQR(f, d, d);
+ if (!MP_EQ(d, cc->c.b)) {
+ MP_DROP(c);
+ MP_DROP(d);
+ MP_DROP(cc->c.a);
+ MP_DROP(cc->c.b);
+ DESTROY(cc);
+ return (0);
+ }
+ cc->bb = c;
+ MP_DROP(d);
return (&cc->c);
}
static const ec_ops ec_binops = {
+ "bin",
ecdestroy, ec_stdsamep, ec_idin, ec_idout, ec_idfix,
ecfind, ecneg, ecadd, ec_stdsub, ecdbl, eccheck
};
static const ec_ops ec_binprojops = {
+ "binproj",
ecdestroy, ec_stdsamep, ec_projin, ec_projout, ec_projfix,
ecfind, ecprojneg, ecprojadd, ec_stdsub, ecprojdbl, ecprojcheck
};
g.x = MP(0x0311103c17167564ace77ccb09c681f886ba54ee8);
g.y = MP(0x333ac13c6447f2e67613bf7009daf98c87bb50c7f);
- for (i = 0; i < n; i++) {
+ for (i = 0; i < n; i++) {
ec_mul(c, &d, &g, r);
if (EC_ATINF(&d)) {
fprintf(stderr, "zero too early\n");
projects / u / mdw / catacomb / blobdiff