diff options
author | Matt Johnston <matt@ucc.asn.au> | 2006-06-10 16:39:40 +0000 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2006-06-10 16:39:40 +0000 |
commit | c9d3c0bc90f21886e0b78595c53e748256e299bf (patch) | |
tree | 0bb2d3bf2f98dae918f07727f55a36d0a637b9f5 /libtommath/bn_mp_rand.c | |
parent | 94d86427ff20ed544e299d3a2de5ecc2cc04c191 (diff) | |
parent | 3b0e6a29698c8580b9556332e678e5301e697959 (diff) |
merge of 332f709a4cb39cde4cedab7c3be89e05f3023067
and ca4ca78b82c5d430c69ce01bf794e8886ce81431
--HG--
extra : convert_revision : 74020525425a1de06739c6c3bed9ef35e4ad867e
Diffstat (limited to 'libtommath/bn_mp_rand.c')
-rw-r--r-- | libtommath/bn_mp_rand.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/libtommath/bn_mp_rand.c b/libtommath/bn_mp_rand.c new file mode 100644 index 0000000..0dc7019 --- /dev/null +++ b/libtommath/bn_mp_rand.c @@ -0,0 +1,51 @@ +#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, tomstdenis@iahu.ca, 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 |