Mercurial > dropbear
view libtommath/bn_mp_rand.c @ 343:ffbe6f691ca3
CHECKCLEARTOWRITE() can normally be defined blank
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sun, 09 Jul 2006 14:58:19 +0000 |
parents | eed26cff980b |
children | 5ff8218bcee9 |
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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 ())) & MP_MASK; } 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