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Man page of BN_rand
BN_rand
Section: OpenSSL (3SSL)
Updated: 20020925
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NAME
BN_rand, BN_pseudo_rand  generate pseudorandom 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 pseudorandom number of
bits bits in length and stores it in rnd. 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.
BN_pseudo_rand() does the same, but pseudorandom numbers generated by
this function are not necessarily unpredictable. They can be used for
noncryptographic purposes and for certain purposes in cryptographic
protocols, but usually not for key generation etc.
BN_rand_range() generates a cryptographically strong pseudorandom
number rnd in the range 0 <lt>= 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).
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.
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUES

 SEE ALSO

 HISTORY

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