5 BN_rand, BN_pseudo_rand - Generate pseudo-random number
9 #include <openssl/bn.h>
11 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
13 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top,int bottom);
17 BN_rand() generates a cryptographically strong pseudo-random number of
18 B<bits> bits in length and stores it in B<rnd>. If B<top> is true, the
19 two most significant bits of the number will be set to 1, so that the
20 product of two such random numbers will always have 2*B<bits> length.
21 If B<bottom> is true, the number will be odd.
23 BN_pseudo_rand() does the same, but pseudo-random numbers generated by
24 this function are not necessarily unpredictable. They can be used for
25 non-cryptographic purposes and for certain purposes in cryptographic
26 protocols, but usually not for key generation etc.
28 The PRNG must be seeded prior to calling BN_rand().
32 BN_rand() and BN_pseudo_rand() return 1 on success, 0 on error.
33 The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
37 L<bn(3)|bn(3)>, L<err(3)|err(3)>, L<rand(3)|rand(3)>,
38 L<RAND_add(3)|RAND_add(3)>, L<RAND_bytes(3)|RAND_bytes(3)>
42 BN_rand() is available in all versions of SSLeay and OpenSSL.
43 BN_pseudo_rand() was added in OpenSSL 0.9.5.