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