| #include <tommath.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, tomstdenis@gmail.com, http://math.libtomcrypt.com |
| */ |
| |
| /* 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 |
| |
| /* $Source: /cvs/libtom/libtommath/bn_mp_dr_is_modulus.c,v $ */ |
| /* $Revision: 1.3 $ */ |
| /* $Date: 2006/03/31 14:18:44 $ */ |
