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BN_RAND(3)			    OpenSSL			    BN_RAND(3)

NAME
       BN_rand,	BN_priv_rand, BN_pseudo_rand, BN_rand_range,
       BN_priv_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_priv_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_priv_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	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_FLG_TOPTWO.

       BN_rand_range() generates a cryptographically strong pseudo-random
       number rnd in the range 0 <= rnd	< range.

       BN_priv_rand() and BN_priv_rand_range() have the	same semantics as
       BN_rand() 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).

NOTES
       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.

RETURN VALUES
       The functions return 1 on success, 0 on error.  The error codes can be
       obtained	by ERR_get_error(3).

HISTORY
       o 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 "pseudo" functions should not	be used	and
	 may be	deprecated in a	future release.

       o BN_priv_rand()	and BN_priv_rand_range() were added in OpenSSL 1.1.1.

SEE ALSO
       ERR_get_error(3), RAND_add(3), RAND_bytes(3), RAND_priv_bytes(3),
       RAND(7),	RAND_DRBG(7)

COPYRIGHT
       Copyright 2000-2018 The OpenSSL Project Authors.	All Rights Reserved.

       Licensed	under the OpenSSL license (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>.

1.1.1a				  2018-11-20			    BN_RAND(3)

NAME | SYNOPSIS | DESCRIPTION | NOTES | RETURN VALUES | HISTORY | SEE ALSO | COPYRIGHT

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