Mercurial > dropbear
diff libtommath/bn_mp_prime_is_divisible.c @ 391:00fcf5045160
propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head c1db4398d56c56c6d06ae1e20c1e0d04dbb598ed)
to branch 'au.asn.ucc.matt.dropbear' (head d26d5eb2837f46b56a33fb0e7573aa0201abd4d5)
author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 11 Jan 2007 04:29:08 +0000 |
parents | 5ff8218bcee9 |
children | 60fc6476e044 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtommath/bn_mp_prime_is_divisible.c Thu Jan 11 04:29:08 2007 +0000 @@ -0,0 +1,50 @@ +#include <tommath.h> +#ifdef BN_MP_PRIME_IS_DIVISIBLE_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://math.libtomcrypt.com + */ + +/* determines if an integers is divisible by one + * of the first PRIME_SIZE primes or not + * + * sets result to 0 if not, 1 if yes + */ +int mp_prime_is_divisible (mp_int * a, int *result) +{ + int err, ix; + mp_digit res; + + /* default to not */ + *result = MP_NO; + + for (ix = 0; ix < PRIME_SIZE; ix++) { + /* what is a mod LBL_prime_tab[ix] */ + if ((err = mp_mod_d (a, ltm_prime_tab[ix], &res)) != MP_OKAY) { + return err; + } + + /* is the residue zero? */ + if (res == 0) { + *result = MP_YES; + return MP_OKAY; + } + } + + return MP_OKAY; +} +#endif + +/* $Source: /cvs/libtom/libtommath/bn_mp_prime_is_divisible.c,v $ */ +/* $Revision: 1.3 $ */ +/* $Date: 2006/03/31 14:18:44 $ */