mirror of
https://github.com/openssl/openssl.git
synced 2024-12-27 06:21:43 +08:00
7d615e2178
The RAND_DRBG API did not fit well into the new provider concept as implemented by EVP_RAND and EVP_RAND_CTX. The main reason is that the RAND_DRBG API is a mixture of 'front end' and 'back end' API calls and some of its API calls are rather low-level. This holds in particular for the callback mechanism (RAND_DRBG_set_callbacks()) and the RAND_DRBG type changing mechanism (RAND_DRBG_set()). Adding a compatibility layer to continue supporting the RAND_DRBG API as a legacy API for a regular deprecation period turned out to come at the price of complicating the new provider API unnecessarily. Since the RAND_DRBG API exists only since version 1.1.1, it was decided by the OMC to drop it entirely. Other related changes: Use RNG instead of DRBG in EVP_RAND documentation. The documentation was using DRBG in places where it should have been RNG or CSRNG. Move the RAND_DRBG(7) documentation to EVP_RAND(7). Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> (Merged from https://github.com/openssl/openssl/pull/12509)
112 lines
3.9 KiB
Plaintext
112 lines
3.9 KiB
Plaintext
=pod
|
|
|
|
=head1 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
|
|
|
|
=head1 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 since OpenSSL 1.1.0, can be hidden entirely by defining
|
|
B<OPENSSL_API_COMPAT> with a suitable version value, see
|
|
L<openssl_user_macros(7)>:
|
|
|
|
int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam);
|
|
void RAND_screen(void);
|
|
|
|
=head1 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
|
|
(L<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 L<RAND(7)> for more details.
|
|
|
|
RAND_status() indicates whether or not the random generator has been sufficiently
|
|
seeded. If not, functions such as L<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 L<RAND(7)> for more details.
|
|
|
|
RAND_add() mixes the B<num> bytes at B<buf> into the internal state
|
|
of the random generator.
|
|
This function will not normally be needed, as mentioned above.
|
|
The B<randomness> argument is an estimate of how much randomness is
|
|
contained in
|
|
B<buf>, in bytes, and should be a number between zero and B<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 B<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 L<RAND_load_file(3)> instead.
|
|
|
|
NOTE: In FIPS mode, random data provided by the application is not considered to
|
|
be a trusted entropy source. It is mixed into the internal state of the RNG as
|
|
additional data only and this does not count as a full reseed.
|
|
For more details, see L<EVP_RAND(7)>.
|
|
|
|
RAND_seed() is equivalent to RAND_add() with B<randomness> set to B<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 B<keep> argument is zero, this call disables the retention of file
|
|
descriptors. Conversely, a nonzero argument enables the retention of
|
|
file descriptors. This function is usually called during initialization
|
|
and it takes effect immediately. This capability only applies to the default
|
|
provider.
|
|
|
|
RAND_event() and RAND_screen() are equivalent to RAND_poll() and exist
|
|
for compatibility reasons only. See HISTORY section below.
|
|
|
|
=head1 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.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<RAND_bytes(3)>,
|
|
L<RAND_egd(3)>,
|
|
L<RAND_load_file(3)>,
|
|
L<RAND(7)>
|
|
L<EVP_RAND(7)>
|
|
|
|
=head1 HISTORY
|
|
|
|
RAND_event() and RAND_screen() were deprecated in OpenSSL 1.1.0 and should
|
|
not be used.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2000-2020 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
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|