Mercurial > dropbear
view bn_mp_rand.c @ 163:8e94663164c6 libtommath LTM_DB_0.44
make pointers volatile so that memory zeroing won't get optimised away
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sun, 02 Jan 2005 17:09:26 +0000 |
parents | d29b64170cf0 |
children | d8254fc979e9 |
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#include <tommath.h> #ifdef BN_MP_RAND_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.org */ /* makes a pseudo-random int of a given size */ int mp_rand (mp_int * a, int digits) { int res; mp_digit d; mp_zero (a); if (digits <= 0) { return MP_OKAY; } /* first place a random non-zero digit */ do { d = ((mp_digit) abs (rand ())); } while (d == 0); if ((res = mp_add_d (a, d, a)) != MP_OKAY) { return res; } while (digits-- > 0) { if ((res = mp_lshd (a, 1)) != MP_OKAY) { return res; } if ((res = mp_add_d (a, ((mp_digit) abs (rand ())), a)) != MP_OKAY) { return res; } } return MP_OKAY; } #endif