BN_rand_ex, BN_rand, BN_priv_rand_ex, BN_priv_rand, BN_pseudo_rand,
BN_rand_range_ex, BN_rand_range, BN_priv_rand_range_ex, BN_priv_rand_range,
BN_pseudo_rand_range - generate pseudo-random number
#include <openssl/bn.h>
int BN_rand_ex(BIGNUM *rnd, int bits, int top, int bottom,
unsigned int strength, BN_CTX *ctx);
int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
int BN_priv_rand_ex(BIGNUM *rnd, int bits, int top, int bottom,
unsigned int strength, BN_CTX *ctx);
int BN_priv_rand(BIGNUM *rnd, int bits, int top, int bottom);
int BN_rand_range_ex(BIGNUM *rnd, const BIGNUM *range, unsigned int strength,
BN_CTX *ctx);
int BN_rand_range(BIGNUM *rnd, const BIGNUM *range);
int BN_priv_rand_range_ex(BIGNUM *rnd, const BIGNUM *range, unsigned int strength,
BN_CTX *ctx);
int BN_priv_rand_range(BIGNUM *rnd, const BIGNUM *range);
The following functions have been deprecated since OpenSSL 3.0, and can be
hidden entirely by defining
OPENSSL_API_COMPAT with a suitable version
value, see
openssl_user_macros(7):
int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
int BN_pseudo_rand_range(BIGNUM *rnd, const BIGNUM *range);
BN_rand_ex() generates a cryptographically strong pseudo-random number of
bits in length and security strength at least
strength bits
using the random number generator for the library context associated with
ctx. The function stores the generated data in
rnd. The
parameter
ctx may be NULL in which case the default library context is
used. If
bits is less than zero, or too small to accommodate the
requirements specified by the
top and
bottom parameters, an
error is returned. The
top parameters specifies requirements on the
most significant bit of the generated number. If it is
BN_RAND_TOP_ANY,
there is no constraint. If it is
BN_RAND_TOP_ONE, the top bit must be
one. If it is
BN_RAND_TOP_TWO, 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
BN_RAND_BOTTOM_ODD, the number will be odd; if it is
BN_RAND_BOTTOM_ANY it can be odd or even. If
bits is 1 then
top cannot also be
BN_RAND_TOP_TWO.
BN_rand() is the same as
BN_rand_ex() except that the default
library context is always used.
BN_rand_range_ex() generates a cryptographically strong pseudo-random
number
rnd, of security strength at least
strength bits, in the
range 0 <=
rnd <
range using the random number generator
for the library context associated with
ctx. The parameter
ctx
may be NULL in which case the default library context is used.
BN_rand_range() is the same as
BN_rand_range_ex() except that the
default library context is always used.
BN_priv_rand_ex(),
BN_priv_rand(),
BN_priv_rand_rand_ex()
and
BN_priv_rand_range() have the same semantics as
BN_rand_ex(),
BN_rand(),
BN_rand_range_ex() and
BN_rand_range() respectively. They are intended to be used for
generating values that should remain private, and mirror the same difference
between
RAND_bytes(3) and
RAND_priv_bytes(3).
Always check the error return value of these functions and do not take
randomness for granted: an error occurs if the CSPRNG has not been seeded with
enough randomness to ensure an unpredictable byte sequence.
The functions return 1 on success, 0 on error. The error codes can be obtained
by
ERR_get_error(3).
ERR_get_error(3),
RAND_add(3),
RAND_bytes(3),
RAND_priv_bytes(3),
RAND(7),
EVP_RAND(7)
- •
- Starting with OpenSSL release 1.1.0,
BN_pseudo_rand() has been identical to BN_rand() and
BN_pseudo_rand_range() has been identical to
BN_rand_range(). The BN_pseudo_rand() and
BN_pseudo_rand_range() functions were deprecated in OpenSSL
3.0.
- •
- The BN_priv_rand() and BN_priv_rand_range()
functions were added in OpenSSL 1.1.1.
- •
- The BN_rand_ex(), BN_priv_rand_ex(),
BN_rand_range_ex() and BN_priv_rand_range_ex() functions
were added in OpenSSL 3.0.
Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy in the
file LICENSE in the source distribution or at
<
https://www.openssl.org/source/license.html>.