mirror of https://github.com/openssl/openssl
119 lines
4.2 KiB
Plaintext
119 lines
4.2 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
RAND_DRBG_reseed,
|
|
RAND_DRBG_set_reseed_interval,
|
|
RAND_DRBG_set_reseed_time_interval,
|
|
RAND_DRBG_set_reseed_defaults
|
|
- reseed a RAND_DRBG instance
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/rand_drbg.h>
|
|
|
|
int RAND_DRBG_reseed(RAND_DRBG *drbg,
|
|
const unsigned char *adin, size_t adinlen,
|
|
int prediction_resistance);
|
|
|
|
int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg,
|
|
unsigned int interval);
|
|
|
|
int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg,
|
|
time_t interval);
|
|
|
|
int RAND_DRBG_set_reseed_defaults(
|
|
unsigned int primary_reseed_interval,
|
|
unsigned int secondary_reseed_interval,
|
|
time_t primary_reseed_time_interval,
|
|
time_t secondary_reseed_time_interval
|
|
);
|
|
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
RAND_DRBG_reseed()
|
|
reseeds the given B<drbg>, obtaining entropy input from its entropy source
|
|
and mixing in the specified additional data provided in the buffer B<adin>
|
|
of length B<adinlen>.
|
|
The additional data can be omitted by setting B<adin> to NULL and B<adinlen>
|
|
to 0.
|
|
An immediate reseeding can be requested by setting the
|
|
B<prediction_resistance> flag to 1.
|
|
Requesting prediction resistance is a relative expensive operation.
|
|
See NOTES section for more details.
|
|
|
|
RAND_DRBG_set_reseed_interval()
|
|
sets the reseed interval of the B<drbg>, which is the maximum allowed number
|
|
of generate requests between consecutive reseedings.
|
|
If B<interval> > 0, then the B<drbg> will reseed automatically whenever the
|
|
number of generate requests since its last seeding exceeds the given reseed
|
|
interval.
|
|
If B<interval> == 0, then this feature is disabled.
|
|
|
|
|
|
RAND_DRBG_set_reseed_time_interval()
|
|
sets the reseed time interval of the B<drbg>, which is the maximum allowed
|
|
number of seconds between consecutive reseedings.
|
|
If B<interval> > 0, then the B<drbg> will reseed automatically whenever the
|
|
elapsed time since its last reseeding exceeds the given reseed time interval.
|
|
If B<interval> == 0, then this feature is disabled.
|
|
|
|
RAND_DRBG_set_reseed_defaults() sets the default values for the reseed interval
|
|
(B<primary_reseed_interval> and B<secondary_reseed_interval>)
|
|
and the reseed time interval
|
|
(B<primary_reseed_time_interval> and B<secondary_reseed_tme_interval>)
|
|
of DRBG instances.
|
|
The default values are set independently for primary DRBG instances (which don't
|
|
have a parent) and secondary DRBG instances (which are chained to a parent
|
|
DRBG).
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
RAND_DRBG_reseed(),
|
|
RAND_DRBG_set_reseed_interval(), and
|
|
RAND_DRBG_set_reseed_time_interval(),
|
|
return 1 on success, 0 on failure.
|
|
|
|
=head1 NOTES
|
|
|
|
The default OpenSSL random generator is already set up for automatic reseeding,
|
|
so in general it is not necessary to reseed it explicitly, or to modify
|
|
its reseeding thresholds.
|
|
|
|
Normally, the entropy input for seeding a DRBG is either obtained from a
|
|
trusted os entropy source or from a parent DRBG instance, which was seeded
|
|
(directly or indirectly) from a trusted os entropy source.
|
|
In exceptional cases it is possible to replace the reseeding mechanism entirely
|
|
by providing application defined callbacks using RAND_DRBG_set_callbacks().
|
|
|
|
The reseeding default values are applied only during creation of a DRBG instance.
|
|
To ensure that they are applied to the global and thread-local DRBG instances
|
|
(<primary>, resp. <public> and <private>), it is necessary to call
|
|
RAND_DRBG_set_reseed_defaults() before creating any thread and before calling
|
|
any cryptographic routines that obtain random data directly or indirectly.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<RAND_DRBG_generate(3)>,
|
|
L<RAND_DRBG_bytes(3)>,
|
|
L<RAND_DRBG_set_callbacks(3)>.
|
|
L<RAND_DRBG(7)>
|
|
|
|
=head1 HISTORY
|
|
|
|
The RAND_DRBG functions were added in OpenSSL 1.1.1.
|
|
|
|
Prediction resistance is supported from OpenSSL 3.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2017-2020 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
|