General utilities cleanup. Add signature support to catcrypt. Throw in

[u/mdw/catacomb] / mpmont.c

diff --git a/mpmont.c b/mpmont.c
index e7b9bb7..39f51ed 100644 (file)
--- a/mpmont.c
+++ b/mpmont.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
 /* -*-c-*-
  *

- * $Id: mpmont.c,v 1.9 2000/06/17 11:45:09 mdw Exp $
+ * $Id: mpmont.c,v 1.19 2004/04/08 01:36:15 mdw Exp $

  *
  * Montgomery reduction
  *
  *
  * Montgomery reduction
  *


@@ -27,45 +27,6 @@
  * MA 02111-1307, USA.
  */
 
  * MA 02111-1307, USA.
  */
 

-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: mpmont.c,v $
- * Revision 1.9  2000/06/17 11:45:09  mdw
- * Major memory management overhaul.  Added arena support.  Use the secure
- * arena for secret integers.  Replace and improve the MP management macros
- * (e.g., replace MP_MODIFY by MP_DEST).
- *
- * Revision 1.8  1999/12/22 15:55:00  mdw
- * Adjust Karatsuba parameters.
- *
- * Revision 1.7  1999/12/11 01:51:14  mdw
- * Use a Karatsuba-based reduction for large moduli.
- *
- * Revision 1.6  1999/12/10 23:18:39  mdw
- * Change interface for suggested destinations.
- *
- * Revision 1.5  1999/11/22 13:58:40  mdw
- * Add an option to disable Montgomery reduction, so that performance
- * comparisons can be done.
- *
- * Revision 1.4  1999/11/21 12:27:06  mdw
- * Remove a division from the Montgomery setup by calculating
- * %$R^2 \bmod m$% first and then %$R \bmod m$% by Montgomery reduction of
- * %$R^2$%.
- *
- * Revision 1.3  1999/11/21 11:35:10  mdw
- * Performance improvement: use @mp_sqr@ and @mpmont_reduce@ instead of
- * @mpmont_mul@ for squaring in exponentiation.
- *
- * Revision 1.2  1999/11/19 13:17:26  mdw
- * Add extra interface to exponentiation which returns a Montgomerized
- * result.
- *
- * Revision 1.1  1999/11/17 18:02:16  mdw
- * New multiprecision integer arithmetic suite.
- *
- */
-

 /*----- Header files ------------------------------------------------------*/
 
 #include "mp.h"
 /*----- Header files ------------------------------------------------------*/
 
 #include "mp.h"


@@ -81,7 +42,7 @@
 
 /* #define MPMONT_DISABLE */
 
 
 /* #define MPMONT_DISABLE */
 

-/*----- Main code ---------------------------------------------------------*/
+/*----- Reduction and multiplication --------------------------------------*/

 
 /* --- @mpmont_create@ --- *
  *
 
 /* --- @mpmont_create@ --- *
  *


@@ -113,15 +74,9 @@ void mpmont_create(mpmont *mm, mp *m)
   mp *r2 = mp_new(2 * n + 1, 0);
   mp r;
 
   mp *r2 = mp_new(2 * n + 1, 0);
   mp r;
 

-  /* --- Validate the arguments --- */
-
-  assert(((void)"Montgomery modulus must be positive",
-         (m->f & MP_NEG) == 0));
-  assert(((void)"Montgomery modulus must be odd", m->v[0] & 1));
-

   /* --- Take a copy of the modulus --- */
 
   /* --- Take a copy of the modulus --- */
 

-  mp_shrink(m);
+  assert(MP_ISPOS(m) && MP_ISODD(m));

   mm->m = MP_COPY(m);
 
   /* --- Determine %$R^2$% --- */
   mm->m = MP_COPY(m);
 
   /* --- Determine %$R^2$% --- */


@@ -133,8 +88,7 @@ void mpmont_create(mpmont *mm, mp *m)
   /* --- Find the magic value @mi@ --- */
 
   mp_build(&r, r2->v + n, r2->vl);
   /* --- Find the magic value @mi@ --- */
 
   mp_build(&r, r2->v + n, r2->vl);

-  mm->mi = MP_NEW;
-  mp_gcd(0, 0, &mm->mi, &r, m);
+  mm->mi = mp_modinv(MP_NEW, m, &r);

   mm->mi = mp_sub(mm->mi, &r, mm->mi);
 
   /* --- Discover the values %$R \bmod m$% and %$R^2 \bmod m$% --- */
   mm->mi = mp_sub(mm->mi, &r, mm->mi);
 
   /* --- Discover the values %$R \bmod m$% and %$R^2 \bmod m$% --- */


@@ -190,7 +144,7 @@ mp *mpmont_reduce(mpmont *mm, mp *d, mp *a)
 
   /* --- Check for serious Karatsuba reduction --- */
 
 
   /* --- Check for serious Karatsuba reduction --- */
 

-  if (n > KARATSUBA_CUTOFF * 3) {
+  if (n > MPK_THRESH * 3) {

     mp al;
     mpw *vl;
     mp *u;
     mp al;
     mpw *vl;
     mp *u;


@@ -241,8 +195,12 @@ mp *mpmont_reduce(mpmont *mm, mp *d, mp *a)
 
   memmove(d->v, d->v + n, MPWS(MP_LEN(d) - n));
   d->vl -= n;
 
   memmove(d->v, d->v + n, MPWS(MP_LEN(d) - n));
   d->vl -= n;

-  if (MP_CMP(d, >=, mm->m))
-    d = mp_sub(d, d, mm->m);
+  if (MPX_UCMP(d->v, d->vl, >=, mm->m->v, mm->m->vl))
+    mpx_usub(d->v, d->vl, d->v, d->vl, mm->m->v, mm->m->vl);
+  if (d->f & MP_NEG) {
+    mpx_usub(d->v, d->vl, mm->m->v, mm->m->vl, d->v, d->vl);
+    d->f &= ~MP_NEG;
+  }

   MP_SHRINK(d);
   return (d);
 }
   MP_SHRINK(d);
   return (d);
 }


@@ -271,7 +229,7 @@ mp *mpmont_mul(mpmont *mm, mp *d, mp *a, mp *b)
 
 mp *mpmont_mul(mpmont *mm, mp *d, mp *a, mp *b)
 {
 
 mp *mpmont_mul(mpmont *mm, mp *d, mp *a, mp *b)
 {

-  if (mm->n > KARATSUBA_CUTOFF * 3) {
+  if (mm->n > MPK_THRESH * 3) {

     d = mp_mul(d, a, b);
     d = mpmont_reduce(mm, d, d);
   } else {
     d = mp_mul(d, a, b);
     d = mpmont_reduce(mm, d, d);
   } else {


@@ -326,10 +284,12 @@ mp *mpmont_mul(mpmont *mm, mp *d, mp *a, mp *b)
 
     memmove(d->v, dv, MPWS(dvl - dv));
     d->vl -= dv - d->v;
 
     memmove(d->v, dv, MPWS(dvl - dv));
     d->vl -= dv - d->v;

+    if (MPX_UCMP(d->v, d->vl, >=, mm->m->v, mm->m->vl))
+      mpx_usub(d->v, d->vl, d->v, d->vl, mm->m->v, mm->m->vl);
+    if ((a->f ^ b->f) & MP_NEG)
+      mpx_usub(d->v, d->vl, mm->m->v, mm->m->vl, d->v, d->vl);

     MP_SHRINK(d);
     d->f = (a->f | b->f) & MP_BURN;
     MP_SHRINK(d);
     d->f = (a->f | b->f) & MP_BURN;

-    if (MP_CMP(d, >=, mm->m))
-      d = mp_sub(d, d, mm->m);

     MP_DROP(a);
     MP_DROP(b);
   }
     MP_DROP(a);
     MP_DROP(b);
   }


@@ -339,69 +299,6 @@ mp *mpmont_mul(mpmont *mm, mp *d, mp *a, mp *b)
 
 #endif
 
 
 #endif
 

-/* --- @mpmont_expr@ --- *
- *
- * Arguments:  @mpmont *mm@ = pointer to Montgomery reduction context
- *             @mp *d@ = fake destination
- *             @mp *a@ = base
- *             @mp *e@ = exponent
- *
- * Returns:    Result, %$a^e R \bmod m$%.
- */
-
-mp *mpmont_expr(mpmont *mm, mp *d, mp *a, mp *e)
-{
-  mpscan sc;
-  mp *ar = mpmont_mul(mm, MP_NEW, a, mm->r2);
-  mp *x = MP_COPY(mm->r);
-  mp *spare = (e->f & MP_BURN) ? MP_NEWSEC : MP_NEW;
-
-  mp_scan(&sc, e);
-
-  if (MP_STEP(&sc)) {
-    size_t sq = 0;
-    for (;;) {
-      mp *dd;
-      if (MP_BIT(&sc)) {
-       while (sq) {
-         dd = mp_sqr(spare, ar);
-         dd = mpmont_reduce(mm, dd, dd);
-         spare = ar; ar = dd;
-         sq--;
-       }
-       dd = mpmont_mul(mm, spare, x, ar);
-       spare = x; x = dd;
-      }
-      sq++;
-      if (!MP_STEP(&sc))
-       break;
-    }
-  }
-  MP_DROP(ar);
-  if (spare != MP_NEW)
-    MP_DROP(spare);
-  if (d != MP_NEW)
-    MP_DROP(d);
-  return (x);
-}
-
-/* --- @mpmont_exp@ --- *
- *
- * Arguments:  @mpmont *mm@ = pointer to Montgomery reduction context
- *             @mp *d@ = fake destination
- *             @mp *a@ = base
- *             @mp *e@ = exponent
- *
- * Returns:    Result, %$a^e \bmod m$%.
- */
-
-mp *mpmont_exp(mpmont *mm, mp *d, mp *a, mp *e)
-{
-  d = mpmont_expr(mm, d, a, e);
-  d = mpmont_reduce(mm, d, d);
-  return (d);
-}
-

 /*----- Test rig ----------------------------------------------------------*/
 
 #ifdef TEST_RIG
 /*----- Test rig ----------------------------------------------------------*/
 
 #ifdef TEST_RIG


@@ -426,7 +323,7 @@ static int tcreate(dstr *v)
     ok = 0;
   }
 
     ok = 0;
   }
 

-  if (MP_CMP(mm.r, !=, r)) {
+  if (!MP_EQ(mm.r, r)) {

     fputs("\n*** bad r", stderr);
     fputs("\nm = ", stderr); mp_writefile(m, stderr, 10);
     fputs("\nexpected ", stderr); mp_writefile(r, stderr, 10);
     fputs("\n*** bad r", stderr);
     fputs("\nm = ", stderr); mp_writefile(m, stderr, 10);
     fputs("\nexpected ", stderr); mp_writefile(r, stderr, 10);


@@ -435,7 +332,7 @@ static int tcreate(dstr *v)
     ok = 0;
   }
 
     ok = 0;
   }
 

-  if (MP_CMP(mm.r2, !=, r2)) {
+  if (!MP_EQ(mm.r2, r2)) {

     fputs("\n*** bad r2", stderr);
     fputs("\nm = ", stderr); mp_writefile(m, stderr, 10);
     fputs("\nexpected ", stderr); mp_writefile(r2, stderr, 10);
     fputs("\n*** bad r2", stderr);
     fputs("\nm = ", stderr); mp_writefile(m, stderr, 10);
     fputs("\nexpected ", stderr); mp_writefile(r2, stderr, 10);


@@ -468,7 +365,7 @@ static int tmul(dstr *v)
     mp *qr = mp_mul(MP_NEW, a, b);
     mp_div(0, &qr, qr, m);
 
     mp *qr = mp_mul(MP_NEW, a, b);
     mp_div(0, &qr, qr, m);
 

-    if (MP_CMP(qr, !=, r)) {
+    if (!MP_EQ(qr, r)) {

       fputs("\n*** classical modmul failed", stderr);
       fputs("\n m = ", stderr); mp_writefile(m, stderr, 10);
       fputs("\n a = ", stderr); mp_writefile(a, stderr, 10);
       fputs("\n*** classical modmul failed", stderr);
       fputs("\n m = ", stderr); mp_writefile(m, stderr, 10);
       fputs("\n a = ", stderr); mp_writefile(a, stderr, 10);


@@ -487,7 +384,7 @@ static int tmul(dstr *v)
     mp *br = mpmont_mul(&mm, MP_NEW, b, mm.r2);
     mp *mr = mpmont_mul(&mm, MP_NEW, ar, br);
     mr = mpmont_reduce(&mm, mr, mr);
     mp *br = mpmont_mul(&mm, MP_NEW, b, mm.r2);
     mp *mr = mpmont_mul(&mm, MP_NEW, ar, br);
     mr = mpmont_reduce(&mm, mr, mr);

-    if (MP_CMP(mr, !=, r)) {
+    if (!MP_EQ(mr, r)) {

       fputs("\n*** montgomery modmul failed", stderr);
       fputs("\n m = ", stderr); mp_writefile(m, stderr, 10);
       fputs("\n a = ", stderr); mp_writefile(a, stderr, 10);
       fputs("\n*** montgomery modmul failed", stderr);
       fputs("\n m = ", stderr); mp_writefile(m, stderr, 10);
       fputs("\n a = ", stderr); mp_writefile(a, stderr, 10);


@@ -511,46 +408,9 @@ static int tmul(dstr *v)
   return ok;
 }
 
   return ok;
 }
 

-static int texp(dstr *v)
-{
-  mp *m = *(mp **)v[0].buf;
-  mp *a = *(mp **)v[1].buf;
-  mp *b = *(mp **)v[2].buf;
-  mp *r = *(mp **)v[3].buf;
-  mp *mr;
-  int ok = 1;
-
-  mpmont mm;
-  mpmont_create(&mm, m);
-
-  mr = mpmont_exp(&mm, MP_NEW, a, b);
-
-  if (MP_CMP(mr, !=, r)) {
-    fputs("\n*** montgomery modexp failed", stderr);
-    fputs("\n m = ", stderr); mp_writefile(m, stderr, 10);
-    fputs("\n a = ", stderr); mp_writefile(a, stderr, 10);
-    fputs("\n e = ", stderr); mp_writefile(b, stderr, 10);
-    fputs("\n r = ", stderr); mp_writefile(r, stderr, 10);
-    fputs("\nmr = ", stderr); mp_writefile(mr, stderr, 10);
-    fputc('\n', stderr);
-    ok = 0;
-  }
-
-  MP_DROP(m);
-  MP_DROP(a);
-  MP_DROP(b);
-  MP_DROP(r);
-  MP_DROP(mr);
-  mpmont_destroy(&mm);
-  assert(mparena_count(MPARENA_GLOBAL) == 0);
-  return ok;
-}
-
-

 static test_chunk tests[] = {
   { "create", tcreate, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },
   { "mul", tmul, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },
 static test_chunk tests[] = {
   { "create", tcreate, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },
   { "mul", tmul, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },

-  { "exp", texp, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },

   { 0, 0, { 0 } },
 };
 
   { 0, 0, { 0 } },
 };