BN_rand - generate pseudo-random number
#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);
BN_rand(3openssl) OpenSSL BN_rand(3openssl)
NAME
BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - generate
pseudo-random number
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);
DESCRIPTION
BN_rand() generates a cryptographically strong pseudo-random number of
bits in length and stores it in rnd. If bits is less than zero, or too
small to accomodate the requirements specified by the top and bottom
parameters, an error is returned. If top is -1, the most significant
bit of the random number can be zero. If top is 0, it is set to 1, and
if 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*bits length. If bottom is true, the number will be odd. The value of
bits must be zero or greater. If bits is 1 then 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 rnd in the range 0 <= rnd < 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().
RETURN VALUES
The functions return 1 on success, 0 on error. The error codes can be
obtained by ERR_get_error(3).
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+--------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------------+
|Availability | library/security/openssl |
+---------------+--------------------------+
|Stability | Pass-through uncommitted |
+---------------+--------------------------+
SEE ALSO
bn(3), ERR_get_error(3), rand(3), RAND_add(3), RAND_bytes(3)
HISTORY
BN_rand() is available in all versions of SSLeay and OpenSSL.
BN_pseudo_rand() was added in OpenSSL 0.9.5. The 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.
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from
https://www.openssl.org/source/openssl-1.0.2ze.tar.gz.
Further information about this software can be found on the open source
community website at https://www.openssl.org/.
1.0.2ze 2022-05-03 BN_rand(3openssl)