view libtommath/bn_mp_dr_is_modulus.c @ 1490:9b87cbe931e3

build: Remove unused constructs: `space' and `AC_PROG_MAKE_SET' The makefile variable `space' is never used. The autoconf output variable `SET_MAKE' is never used, so the autoconf macro `AC_PROG_MAKE_SET' has been removed.
author Michael Witten <mfwitten@gmail.com>
date Mon, 31 Jul 2017 23:55:52 +0000
parents 8bba51a55704
children f52919ffd3b1
line wrap: on
line source
#include <tommath_private.h>
#ifdef BN_MP_DR_IS_MODULUS_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
 *
 * LibTomMath is a library that provides multiple-precision
 * integer arithmetic as well as number theoretic functionality.
 *
 * The library was designed directly after the MPI library by
 * Michael Fromberger but has been written from scratch with
 * additional optimizations in place.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [email protected], http://libtom.org
 */

/* determines if a number is a valid DR modulus */
int mp_dr_is_modulus(mp_int *a)
{
   int ix;

   /* must be at least two digits */
   if (a->used < 2) {
      return 0;
   }

   /* must be of the form b**k - a [a <= b] so all
    * but the first digit must be equal to -1 (mod b).
    */
   for (ix = 1; ix < a->used; ix++) {
       if (a->dp[ix] != MP_MASK) {
          return 0;
       }
   }
   return 1;
}

#endif

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