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authorKevin B Kenny <kennykb@acm.org>2005-01-19 22:41:26 (GMT)
committerKevin B Kenny <kennykb@acm.org>2005-01-19 22:41:26 (GMT)
commitb9cf65a08e6a59e434685e894e3189c201ac6791 (patch)
tree1f0868ef44c9f17d83d10dc94343df7b8cfe1842 /libtommath/bn_mp_rand.c
parentc6a259aeeca4814a97cf6694814c63e74e4e18fa (diff)
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Import of libtommath 0.33
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 ()));
+ } 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