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RAND_ADD(3)			    OpenSSL			   RAND_ADD(3)

NAME
       RAND_add, RAND_poll, RAND_seed, RAND_status, RAND_event,	RAND_screen,
       RAND_keep_random_devices_open - add randomness to the PRNG or get its
       status

SYNOPSIS
	#include <openssl/rand.h>

	int RAND_status(void);
	int RAND_poll();

	void RAND_add(const void *buf, int num,	double randomness);
	void RAND_seed(const void *buf,	int num);

	void RAND_keep_random_devices_open(int keep);

       Deprecated:

	#if OPENSSL_API_COMPAT < 0x10100000L
	int RAND_event(UINT iMsg, WPARAM wParam, LPARAM	lParam);
	void RAND_screen(void);
	#endif

DESCRIPTION
       These functions can be used to seed the random generator	and to check
       its seeded state.  In general, manual (re-)seeding of the default
       OpenSSL random generator	(RAND_OpenSSL(3)) is not necessary (but
       allowed), since it does (re-)seed itself	automatically using trusted
       system entropy sources.	This holds unless the default RAND_METHOD has
       been replaced or	OpenSSL	was built with automatic reseeding disabled,
       see RAND(7) for more details.

       RAND_status() indicates whether or not the random generator has been
       sufficiently seeded. If not, functions such as RAND_bytes(3) will fail.

       RAND_poll() uses	the system's capabilities to seed the random generator
       using random input obtained from	polling	various	trusted	entropy
       sources.	 The default choice of the entropy source can be modified at
       build time, see RAND(7) for more	details.

       RAND_add() mixes	the num	bytes at buf into the internal state of	the
       random generator.  This function	will not normally be needed, as
       mentioned above.	 The randomness	argument is an estimate	of how much
       randomness is contained in buf, in bytes, and should be a number
       between zero and	num.  Details about sources of randomness and how to
       estimate	their randomness can be	found in the literature; for example
       [NIST SP	800-90B].  The content of buf cannot be	recovered from
       subsequent random generator output.  Applications that intend to	save
       and restore random state	in an external file should consider using
       RAND_load_file(3) instead.

       RAND_seed() is equivalent to RAND_add() with randomness set to num.

       RAND_keep_random_devices_open() is used to control file descriptor
       usage by	the random seed	sources. Some seed sources maintain open file
       descriptors by default, which allows such sources to operate in a
       chroot(2) jail without the associated device nodes being	available.
       When the	keep argument is zero, this call disables the retention	of
       file descriptors. Conversely, a non-zero	argument enables the retention
       of file descriptors. This function is usually called during
       initialization and it takes effect immediately.

       RAND_event() and	RAND_screen() are equivalent to	RAND_poll() and	exist
       for compatibility reasons only. See HISTORY section below.

RETURN VALUES
       RAND_status() returns 1 if the random generator has been	seeded with
       enough data, 0 otherwise.

       RAND_poll() returns 1 if	it generated seed data,	0 otherwise.

       RAND_event() returns RAND_status().

       The other functions do not return values.

HISTORY
       RAND_event() and	RAND_screen() were deprecated in OpenSSL 1.1.0 and
       should not be used.

SEE ALSO
       RAND_bytes(3), RAND_egd(3), RAND_load_file(3), RAND(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			   RAND_ADD(3)

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

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