You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
59 lines
2.0 KiB
59 lines
2.0 KiB
=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); |
|
|
|
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
|
|
|