ec3a7c9b37
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit d900a015b5)
59 lines
2 KiB
Text
59 lines
2 KiB
Text
=pod
|
|
|
|
=head1 NAME
|
|
|
|
BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - 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);
|
|
|
|
int BN_rand_range(BIGNUM *rnd, BIGNUM *range);
|
|
|
|
int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
BN_rand() generates a cryptographically strong pseudo-random number of
|
|
B<bits> in length and stores it in B<rnd>. If B<top> is -1, the
|
|
most significant bit of the random number can be zero. If B<top> is 0,
|
|
it is set to 1, and if B<top> is 1, 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. The value of B<bits> must be zero or greater. If B<bits> is
|
|
1 then B<top> cannot also be 1.
|
|
|
|
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.
|
|
|
|
BN_rand_range() generates a cryptographically strong pseudo-random
|
|
number B<rnd> in the range 0 E<lt>= B<rnd> E<lt> B<range>.
|
|
BN_pseudo_rand_range() does the same, but is based on BN_pseudo_rand(),
|
|
and hence numbers generated by it are not necessarily unpredictable.
|
|
|
|
The PRNG must be seeded prior to calling BN_rand() or BN_rand_range().
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
The functions 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_get_error(3)|ERR_get_error(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. The B<top> == -1 case
|
|
and the function BN_rand_range() were added in OpenSSL 0.9.6a.
|
|
BN_pseudo_rand_range() was added in OpenSSL 0.9.6c.
|
|
|
|
=cut
|