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authorMatt Johnston <matt@ucc.asn.au>2006-06-10 16:39:40 +0000
committerMatt Johnston <matt@ucc.asn.au>2006-06-10 16:39:40 +0000
commitc9d3c0bc90f21886e0b78595c53e748256e299bf (patch)
tree0bb2d3bf2f98dae918f07727f55a36d0a637b9f5 /libtommath/bn_mp_rand.c
parent94d86427ff20ed544e299d3a2de5ecc2cc04c191 (diff)
parent3b0e6a29698c8580b9556332e678e5301e697959 (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.c51
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
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+++ b/libtommath/bn_mp_rand.c
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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, 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