X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/02d7884df1f33c9c7dc3a14c4b1a5f520ebe090a..a1e745ad3b306d1e5173588e39d71b132466365e:/g-prime.c

diff --git a/g-prime.c b/g-prime.c
index 03cce55..5230111 100644
--- a/g-prime.c
+++ b/g-prime.c
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: g-prime.c,v 1.2 2004/04/03 03:32:05 mdw Exp $
+ * $Id$
  *
  * Abstraction for prime groups
  *
  * (c) 2004 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of Catacomb.
  *
@@ -15,33 +15,18 @@
  * 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: g-prime.c,v $
- * Revision 1.2  2004/04/03 03:32:05  mdw
- * General robustification.
- *
- * Revision 1.1  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.)
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include <mLib/sub.h>
@@ -51,21 +36,14 @@
 
 #define ge mp *
 #include "group.h"
-
-/*----- Data structures ---------------------------------------------------*/
-
-typedef struct gctx {
-  group g;
-  mp *gen;
-  mpmont mm;
-} gctx;
+#include "group-guts.h"
 
 /*----- Main code ---------------------------------------------------------*/
 
 /* --- Group operations --- */
 
 static void gdestroygroup(group *gg) {
-  gctx *g = (gctx *)gg;
+  gctx_prime *g = (gctx_prime *)gg;
   mp_drop(g->gen); mp_drop(g->g.r); mp_drop(g->g.h);
   mpmont_destroy(&g->mm);
   DESTROY(g);
@@ -82,14 +60,14 @@ static void gburn(group *gg, mp **x) { (*x)->f |= MP_BURN; }
 static void gdestroy(group *gg, mp **x) { MP_DROP(*x); DESTROY(x); }
 
 static int gsamep(group *gg, group *hh) {
-  gctx *g = (gctx *)gg, *h = (gctx *)hh;
+  gctx_prime *g = (gctx_prime *)gg, *h = (gctx_prime *)hh;
   return (MP_EQ(g->mm.m, h->mm.m));
 }
 
 static int geq(group *gg, mp **x, mp **y) { return (MP_EQ(*x, *y)); }
 
 static const char *gcheck(group *gg, grand *gr) {
-  gctx *g = (gctx *)gg; int rc; mp *t;
+  gctx_prime *g = (gctx_prime *)gg; int rc; mp *t;
   if (!pgen_primep(g->mm.m, gr)) return ("p is not prime");
   t = mp_mul(MP_NEW, g->g.r, g->g.h); t = mp_add(t, t, MP_ONE);
   rc = MP_EQ(t, g->mm.m); MP_DROP(t); if (!rc) return ("not a subgroup");
@@ -97,54 +75,74 @@ static const char *gcheck(group *gg, grand *gr) {
 }
 
 static void gmul(group *gg, mp **d, mp **x, mp **y)
-  { gctx *g = (gctx *)gg; *d = mpmont_mul(&g->mm, *d, *x, *y); }
+  { gctx_prime *g = (gctx_prime *)gg; *d = mpmont_mul(&g->mm, *d, *x, *y); }
 
 static void gsqr(group *gg, mp **d, mp **x) {
-  gctx *g = (gctx *)gg; mp *r = mp_sqr(*d, *x);
+  gctx_prime *g = (gctx_prime *)gg; mp *r = mp_sqr(*d, *x);
   *d = mpmont_reduce(&g->mm, r, r);
 }
 
 static void ginv(group *gg, mp **d, mp **x) {
-  gctx *g = (gctx *)gg; mp *r = mpmont_reduce(&g->mm, *d, *x);
-  mp_gcd(0, 0, &r, g->mm.m, r); *d = mpmont_mul(&g->mm, r, r, g->mm.r2);
+  gctx_prime *g = (gctx_prime *)gg; mp *r = mpmont_reduce(&g->mm, *d, *x);
+  r = mp_modinv(r, r, g->mm.m); *d = mpmont_mul(&g->mm, r, r, g->mm.r2);
 }
 
 static void gexp(group *gg, mp **d, mp **x, mp *n)
-  { gctx *g = (gctx *)gg; *d = mpmont_expr(&g->mm, *d, *x, n); }
+  { gctx_prime *g = (gctx_prime *)gg; *d = mpmont_expr(&g->mm, *d, *x, n); }
 
 static void gmexp(group *gg, mp **d, const group_expfactor *f, size_t n) {
-  gctx *g = (gctx *)gg; size_t i;
+  gctx_prime *g = (gctx_prime *)gg; size_t i;
   mp_expfactor *ff = xmalloc(n * sizeof(mp_expfactor));
   for (i = 0; i < n; i++) { ff[i].base = *f[i].base; ff[i].exp = f[i].exp; }
   *d = mpmont_mexpr(&g->mm, *d, ff, n); xfree(ff);
 }
 
 static int gread(group *gg, mp **d, const mptext_ops *ops, void *p) {
-  gctx *g = (gctx *)gg; mp *t;
+  gctx_prime *g = (gctx_prime *)gg; mp *t;
   if ((t = mp_read(MP_NEW, 0, ops, p)) == 0) return (-1);
   mp_drop(*d); *d = mpmont_mul(&g->mm, t, t, g->mm.r2); return (0);
 }
 
 static int gwrite(group *gg, mp **x, const mptext_ops *ops, void *p) {
-  gctx *g = (gctx *)gg; mp *t = mpmont_reduce(&g->mm, MP_NEW, *x);
+  gctx_prime *g = (gctx_prime *)gg;
+  mp *t = mpmont_reduce(&g->mm, MP_NEW, *x);
   int rc = mp_write(t, 10, ops, p); MP_DROP(t); return (rc);
 }
 
-static mp *gtoint(group *gg, mp *d, mp **x)
-  { gctx *g = (gctx *)gg; return (mpmont_reduce(&g->mm, d, *x)); }
+static mp *gtoint(group *gg, mp *d, mp **x) {
+  gctx_prime *g = (gctx_prime *)gg;
+  return (mpmont_reduce(&g->mm, d, *x));
+}
 
 static int gfromint(group *gg, mp **d, mp *x) {
-  gctx *g = (gctx *)gg; mp_div(0, &x, x, g->mm.m); mp_drop(*d);
-  *d = mpmont_mul(&g->mm, x, x, g->mm.r2); return (0);
+  gctx_prime *g = (gctx_prime *)gg; mp_div(0, d, x, g->mm.m);
+  *d = mpmont_mul(&g->mm, *d, *d, g->mm.r2); return (0);
 }
 
 static int gtobuf(group *gg, buf *b, mp **x) {
-  gctx *g = (gctx *)gg; mp *t = mpmont_reduce(&g->mm, MP_NEW, *x);
+  gctx_prime *g = (gctx_prime *)gg;
+  mp *t = mpmont_reduce(&g->mm, MP_NEW, *x);
   int rc = buf_putmp(b, t); MP_DROP(t); return (rc);
 }
 
 static int gfrombuf(group *gg, buf *b, mp **d) {
-  gctx * g = (gctx *)gg; mp *x; if ((x = buf_getmp(b)) == 0) return (-1);
+  gctx_prime * g = (gctx_prime *)gg; mp *x;
+  if ((x = buf_getmp(b)) == 0) return (-1);
+  mp_div(0, &x, x, g->mm.m); mp_drop(*d);
+  *d = mpmont_mul(&g->mm, x, x, g->mm.r2); return(0);
+}
+
+static int gtoraw(group *gg, buf *b, mp **x) {
+  gctx_prime *g = (gctx_prime *)gg; octet *q;
+  mp *t = mpmont_reduce(&g->mm, MP_NEW, *x);
+  if ((q = buf_get(b, g->g.noctets)) == 0) { MP_DROP(t); return (-1); }
+  mp_storeb(t, q, g->g.noctets); MP_DROP(t); return (0);
+}
+
+static int gfromraw(group *gg, buf *b, mp **d) {
+  gctx_prime * g = (gctx_prime *)gg; mp *x; octet *q;
+  if ((q = buf_get(b, g->g.noctets)) == 0) return (-1);
+  x = mp_loadb(MP_NEW, q, g->g.noctets);
   mp_div(0, &x, x, g->mm.m); mp_drop(*d);
   *d = mpmont_mul(&g->mm, x, x, g->mm.r2); return(0);
 }
@@ -160,22 +158,23 @@ static int gfrombuf(group *gg, buf *b, mp **d) {
  */
 
 static const group_ops gops = {
-  GTY_PRIME,
+  GTY_PRIME, "prime",
   gdestroygroup, gcreate, gcopy, gburn, gdestroy,
   gsamep, geq, group_stdidentp,
   gcheck,
   gmul, gsqr, ginv, group_stddiv, gexp, gmexp,
   gread, gwrite,
-  gtoint, gfromint, group_stdtoec, group_stdfromec, gtobuf, gfrombuf
+  gtoint, gfromint, group_stdtoec, group_stdfromec, gtobuf, gfrombuf,
+  gtoraw, gfromraw
 };
 
 group *group_prime(const gprime_param *gp)
 {
-  gctx *g;
+  gctx_prime *g;
 
-  if (!MP_ISPOS(gp->p) || !MP_ISODD(gp->p))
+  if (!MP_POSP(gp->p) || !MP_ODDP(gp->p))
     return (0);
-  g = CREATE(gctx);
+  g = CREATE(gctx_prime);
   g->g.ops = &gops;
   g->g.nbits = mp_bits(gp->p);
   g->g.noctets = (g->g.nbits + 7) >> 3;