/* -*-c-*-
*
- * $Id: f-prime.c,v 1.7 2004/03/27 17:54:11 mdw Exp $
+ * $Id$
*
* Prime fields with Montgomery arithmetic
*
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: f-prime.c,v $
- * 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.
- *
- * Revision 1.3.4.2 2004/03/20 00:13:31 mdw
- * Projective coordinates for prime curves
- *
- * Revision 1.3.4.1 2003/06/10 13:43:53 mdw
- * Simple (non-projective) curves over prime fields now seem to work.
- *
- * Revision 1.3 2003/05/15 23:25:59 mdw
- * Make elliptic curve stuff build.
- *
- * Revision 1.2 2002/01/13 13:48:44 mdw
- * Further progress.
- *
- * Revision 1.1 2001/04/29 18:12:33 mdw
- * Prototype version.
- *
- */
-
/*----- Header files ------------------------------------------------------*/
#include <mLib/sub.h>
#include "field.h"
-#include "mpmont.h"
#include "mprand.h"
-
-/*----- Data structures ---------------------------------------------------*/
-
-typedef struct fctx {
- field f;
- mpmont mm;
-} fctx;
+#include "field-guts.h"
/*----- Main code ---------------------------------------------------------*/
/* --- Field operations --- */
-static void fdestroy(field *ff)
-{
- fctx *f = (fctx *)ff;
+static void fdestroy(field *ff) {
+ fctx_prime *f = (fctx_prime *)ff;
mpmont_destroy(&f->mm);
DESTROY(f);
}
-static mp *frand(field *ff, mp *d, grand *r)
-{
- fctx *f = (fctx *)ff;
+static mp *frand(field *ff, mp *d, grand *r) {
+ fctx_prime *f = (fctx_prime *)ff;
return (mprand_range(d, f->mm.m, r, 0));
}
-static mp *fin(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
+static mp *fin(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff;
mp_div(0, &d, x, f->mm.m);
return (mpmont_mul(&f->mm, d, d, f->mm.r2));
}
-static mp *fout(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
+static mp *fout(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff;
return (mpmont_reduce(&f->mm, d, x));
}
-static int fzerop(field *ff, mp *x)
-{
- return (!MP_LEN(x));
-}
+static int fzerop(field *ff, mp *x) { return (MP_ZEROP(x)); }
-static mp *fneg(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
+static mp *fneg(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff;
return (mp_sub(d, f->mm.m, x));
}
-static mp *fadd(field *ff, mp *d, mp *x, mp *y)
-{
- fctx *f = (fctx *)ff;
- d = mp_add(d, x, y);
- if (d->f & MP_NEG)
- d = mp_add(d, d, f->mm.m);
- else if (MP_CMP(d, >, f->mm.m))
- d = mp_sub(d, d, f->mm.m);
+static mp *fadd(field *ff, mp *d, mp *x, mp *y) {
+ fctx_prime *f = (fctx_prime *)ff; d = mp_add(d, x, y);
+ if (MP_NEGP(d)) d = mp_add(d, d, f->mm.m);
+ else if (MP_CMP(d, >, f->mm.m)) d = mp_sub(d, d, f->mm.m);
return (d);
}
-static mp *fsub(field *ff, mp *d, mp *x, mp *y)
-{
- fctx *f = (fctx *)ff;
- d = mp_sub(d, x, y);
- if (d->f & MP_NEG)
- d = mp_add(d, d, f->mm.m);
- else if (MP_CMP(d, >, f->mm.m))
- d = mp_sub(d, d, f->mm.m);
+static mp *fsub(field *ff, mp *d, mp *x, mp *y) {
+ fctx_prime *f = (fctx_prime *)ff; d = mp_sub(d, x, y);
+ if (MP_NEGP(d)) d = mp_add(d, d, f->mm.m);
+ else if (MP_CMP(d, >, f->mm.m)) d = mp_sub(d, d, f->mm.m);
return (d);
}
-static mp *fmul(field *ff, mp *d, mp *x, mp *y)
-{
- fctx *f = (fctx *)ff;
+static mp *fmul(field *ff, mp *d, mp *x, mp *y) {
+ fctx_prime *f = (fctx_prime *)ff;
return (mpmont_mul(&f->mm, d, x, y));
}
-static mp *fsqr(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
- d = mp_sqr(d, x);
+static mp *fsqr(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff; d = mp_sqr(d, x);
return (mpmont_reduce(&f->mm, d, d));
}
-static mp *finv(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
- d = mpmont_reduce(&f->mm, d, x);
- mp_gcd(0, 0, &d, f->mm.m, d);
- return (mpmont_mul(&f->mm, d, d, f->mm.r2));
+static mp *finv(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff; d = mpmont_reduce(&f->mm, d, x);
+ d = mp_modinv(d, d, f->mm.m); return (mpmont_mul(&f->mm, d, d, f->mm.r2));
}
-static mp *freduce(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
+static mp *freduce(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff;
mp_div(0, &d, x, f->mm.m);
return (d);
}
-static mp *fsqrt(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
- d = mpmont_reduce(&f->mm, d, x);
- d = mp_modsqrt(d, d, f->mm.m);
- if (!d)
- return (d);
+static mp *fsqrt(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff; d = mpmont_reduce(&f->mm, d, x);
+ d = mp_modsqrt(d, d, f->mm.m); if (!d) return (d);
return (mpmont_mul(&f->mm, d, d, f->mm.r2));
}
-static mp *fdbl(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
- d = mp_lsl(d, x, 1);
- if (MP_CMP(d, >, f->mm.m))
- d = mp_sub(d, d, f->mm.m);
+static mp *fdbl(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff; d = mp_lsl(d, x, 1);
+ if (MP_CMP(d, >=, f->mm.m)) d = mp_sub(d, d, f->mm.m);
return (d);
}
-static mp *ftpl(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
- MP_DEST(d, MP_LEN(x) + 1, x->f);
- MPX_UMULN(d->v, d->vl, x->v, x->vl, 3);
- while (MP_CMP(d, >, f->mm.m))
- d = mp_sub(d, d, f->mm.m);
+static mp *ftpl(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff; MP_DEST(d, MP_LEN(x) + 1, x->f);
+ MPX_UMULN(d->v, d->vl, x->v, x->vl, 3); d->f &= ~MP_UNDEF;
+ while (MP_CMP(d, >=, f->mm.m)) d = mp_sub(d, d, f->mm.m);
return (d);
}
-static mp *fqdl(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
- d = mp_lsl(d, x, 2);
- while (MP_CMP(d, >, f->mm.m))
- d = mp_sub(d, d, f->mm.m);
+static mp *fqdl(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff; d = mp_lsl(d, x, 2);
+ while (MP_CMP(d, >=, f->mm.m)) d = mp_sub(d, d, f->mm.m);
return (d);
}
-static mp *fhlv(field *ff, mp *d, mp *x)
-{
- fctx *f = (fctx *)ff;
- if (!MP_LEN(x)) {
- MP_COPY(x);
- MP_DROP(d);
- return (x);
- }
- if (x->v[0] & 1) {
- d = mp_add(d, x, f->mm.m);
- x = d;
- }
+static mp *fhlv(field *ff, mp *d, mp *x) {
+ fctx_prime *f = (fctx_prime *)ff;
+ if (MP_ZEROP(x)) { MP_COPY(x); MP_DROP(d); return (x); }
+ if (x->v[0] & 1) { d = mp_add(d, x, f->mm.m); x = d; }
return (mp_lsr(d, x, 1));
}
/* --- Field operations table --- */
-static field_ops fops = {
+static const field_ops fops = {
FTY_PRIME, "prime",
- fdestroy, frand,
+ fdestroy, frand, field_stdsamep,
fin, fout,
fzerop, fneg, fadd, fsub, fmul, fsqr, finv, freduce, fsqrt,
0,
*
* Arguments: @mp *p@ = the characteristic of the field
*
- * Returns: A pointer to the field.
+ * Returns: A pointer to the field or null.
*
* Use: Creates a field structure for a prime field of size %$p$%,
* using Montgomery reduction for arithmetic.
field *field_prime(mp *p)
{
- fctx *f = CREATE(fctx);
+ fctx_prime *f;
+
+ f = CREATE(fctx_prime);
f->f.ops = &fops;
- mpmont_create(&f->mm, p);
+ if (mpmont_create(&f->mm, p)) {
+ DESTROY(f);
+ return (0);
+ }
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;
+ f->f.q = f->mm.m;
return (&f->f);
}
projects / u / mdw / catacomb / blobdiff