Mercurial > dropbear
comparison bn_mp_dr_is_modulus.c @ 282:91fbc376f010 libtommath-orig libtommath-0.35
Import of libtommath 0.35
From ltm-0.35.tar.bz2 SHA1 of 3f193dbae9351e92d02530994fa18236f7fde01c
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Wed, 08 Mar 2006 13:16:18 +0000 |
| parents | |
| children | 97db060d0ef5 |
comparison
equal
deleted
inserted
replaced
| -1:000000000000 | 282:91fbc376f010 |
|---|---|
| 1 #include <tommath.h> | |
| 2 #ifdef BN_MP_DR_IS_MODULUS_C | |
| 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis | |
| 4 * | |
| 5 * LibTomMath is a library that provides multiple-precision | |
| 6 * integer arithmetic as well as number theoretic functionality. | |
| 7 * | |
| 8 * The library was designed directly after the MPI library by | |
| 9 * Michael Fromberger but has been written from scratch with | |
| 10 * additional optimizations in place. | |
| 11 * | |
| 12 * The library is free for all purposes without any express | |
| 13 * guarantee it works. | |
| 14 * | |
| 15 * Tom St Denis, [email protected], http://math.libtomcrypt.org | |
| 16 */ | |
| 17 | |
| 18 /* determines if a number is a valid DR modulus */ | |
| 19 int mp_dr_is_modulus(mp_int *a) | |
| 20 { | |
| 21 int ix; | |
| 22 | |
| 23 /* must be at least two digits */ | |
| 24 if (a->used < 2) { | |
| 25 return 0; | |
| 26 } | |
| 27 | |
| 28 /* must be of the form b**k - a [a <= b] so all | |
| 29 * but the first digit must be equal to -1 (mod b). | |
| 30 */ | |
| 31 for (ix = 1; ix < a->used; ix++) { | |
| 32 if (a->dp[ix] != MP_MASK) { | |
| 33 return 0; | |
| 34 } | |
| 35 } | |
| 36 return 1; | |
| 37 } | |
| 38 | |
| 39 #endif |