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author | Matt Johnston <matt@ucc.asn.au> | 2006-03-08 13:23:49 +0000 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2006-03-08 13:23:49 +0000 |
commit | 475aa151f9618036b90a25cf529517d04e61977f (patch) | |
tree | 453ebf8873dd287a2def6a674d42afcc6637cde2 /libtommath/bn_mp_rand.c | |
parent | 2514a6739b3268c98ef09863eff52ed086e4b6f9 (diff) | |
parent | 2b43e46e826fe9905f36b8920386e13f1f47ed65 (diff) | |
download | dropbear-475aa151f9618036b90a25cf529517d04e61977f.tar.gz |
propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)
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 |