1/*	$NetBSD$	*/
2
3#include <tommath.h>
4#ifdef BN_MP_DR_IS_MODULUS_C
5/* LibTomMath, multiple-precision integer library -- Tom St Denis
6 *
7 * LibTomMath is a library that provides multiple-precision
8 * integer arithmetic as well as number theoretic functionality.
9 *
10 * The library was designed directly after the MPI library by
11 * Michael Fromberger but has been written from scratch with
12 * additional optimizations in place.
13 *
14 * The library is free for all purposes without any express
15 * guarantee it works.
16 *
17 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
18 */
19
20/* determines if a number is a valid DR modulus */
21int mp_dr_is_modulus(mp_int *a)
22{
23   int ix;
24
25   /* must be at least two digits */
26   if (a->used < 2) {
27      return 0;
28   }
29
30   /* must be of the form b**k - a [a <= b] so all
31    * but the first digit must be equal to -1 (mod b).
32    */
33   for (ix = 1; ix < a->used; ix++) {
34       if (a->dp[ix] != MP_MASK) {
35          return 0;
36       }
37   }
38   return 1;
39}
40
41#endif
42
43/* Source: /cvs/libtom/libtommath/bn_mp_dr_is_modulus.c,v */
44/* Revision: 1.4 */
45/* Date: 2006/12/28 01:25:13 */
46