openssl/doc/crypto/BN_rand.pod
2000-02-24 11:55:57 +00:00

45 lines
1.3 KiB
Text

=pod
=head1 NAME
BN_rand, BN_pseudo_rand - generate pseudo-random number
=head1 SYNOPSIS
#include <openssl/bn.h>
int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
=head1 DESCRIPTION
BN_rand() generates a cryptographically strong pseudo-random number of
B<bits> bits in length and stores it in B<rnd>. If B<top> is true, the
two most significant bits of the number will be set to 1, so that the
product of two such random numbers will always have 2*B<bits> length.
If B<bottom> is true, the number will be odd.
BN_pseudo_rand() does the same, but pseudo-random numbers generated by
this function are not necessarily unpredictable. They can be used for
non-cryptographic purposes and for certain purposes in cryptographic
protocols, but usually not for key generation etc.
The PRNG must be seeded prior to calling BN_rand().
=head1 RETURN VALUES
BN_rand() and BN_pseudo_rand() return 1 on success, 0 on error.
The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
=head1 SEE ALSO
L<bn(3)|bn(3)>, L<err(3)|err(3)>, L<rand(3)|rand(3)>,
L<RAND_add(3)|RAND_add(3)>, L<RAND_bytes(3)|RAND_bytes(3)>
=head1 HISTORY
BN_rand() is available in all versions of SSLeay and OpenSSL.
BN_pseudo_rand() was added in OpenSSL 0.9.5.
=cut