Mercurial > dropbear
view libtommath/bn_mp_dr_is_modulus.c @ 1493:72fd994fe7bd
Update build instructions for localoptions, and tidy
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 14 Feb 2018 00:24:32 +0800 |
parents | 8bba51a55704 |
children | f52919ffd3b1 |
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#include <tommath_private.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, [email protected], http://libtom.org */ /* 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 /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */