75e2c87765
If RAND_add wraps around, XOR with existing. Add test to drbgtest that
does the wrap-around.
Re-order seeding and stop after first success.
Add RAND_poll_ex()
Use the DF and therefore lower RANDOMNESS_NEEDED. Also, for child DRBG's,
mix in the address as the personalization bits.
Centralize the entropy callbacks, from drbg_lib to rand_lib.
(Conceptually, entropy is part of the enclosing application.)
Thanks to Dr. Matthias St Pierre for the suggestion.
Various code cleanups:
-Make state an enum; inline RANDerr calls.
-Add RAND_POLL_RETRIES (thanks Pauli for the idea)
-Remove most RAND_seed calls from rest of library
-Rename DRBG_CTX to RAND_DRBG, etc.
-Move some code from drbg_lib to drbg_rand; drbg_lib is now only the
implementation of NIST DRBG.
-Remove blocklength
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4019)
100 lines
3.4 KiB
Text
100 lines
3.4 KiB
Text
=pod
|
|
|
|
=head1 NAME
|
|
|
|
RAND_add, RAND_poll, RAND_poll_ex, RAND_poll_fn,
|
|
RAND_seed, RAND_status, RAND_event, RAND_screen
|
|
- add randomness to the PRNG or get its status
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/rand.h>
|
|
|
|
int RAND_status(void);
|
|
|
|
typedef void (*RAND_poll_fn)(void *arg,
|
|
const void *buf, int num, double randomness);
|
|
int RAND_poll_ex(RAND_poll_fn cb, void *arg);
|
|
int RAND_poll();
|
|
|
|
void RAND_add(const void *buf, int num, double randomness);
|
|
void RAND_seed(const void *buf, int num);
|
|
|
|
Deprecated:
|
|
|
|
#if OPENSSL_API_COMPAT < 0x10100000L
|
|
int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam);
|
|
void RAND_screen(void);
|
|
#endif
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
Random numbers are a vital part of cryptography, including key generation,
|
|
creating salts, etc., and software-based
|
|
generators must be "seeded" with external randomness before they can be
|
|
used as a cryptographically-secure pseudo-random number generator (CSPRNG).
|
|
The availability of common hardware with special instructions and
|
|
modern operating systems, which may use items such as interrupt jitter
|
|
and network packet timings, can be reasonable sources of seeding material.
|
|
|
|
RAND_status() indicates whether or not the CSPRNG has been sufficiently
|
|
seeded. If not, functions such as RAND_bytes(3) will fail.
|
|
|
|
RAND_poll_ex() uses the system's capabilities to obtain a buffer
|
|
containing random bits which can then be used to seed a CSPRNG. The
|
|
exact features used depends on how OpenSSL was configured, and a summary
|
|
can be displayed with the OpenSSL L<version(1)> command. This function
|
|
is normally called as needed by the CSPRNG. The B<arg> parameter is an
|
|
arbitrary pointer which will be passed as an argument to the callback.
|
|
The B<cb> function is called each time there is data to add.
|
|
|
|
RAND_poll() invokes RAND_poll_ex() with B<cb> and B<arg> set so that it
|
|
will call RAND_add(), to add the randomness to the global CSPRNG.
|
|
|
|
RAND_add() mixes the B<num> bytes at B<buf> into the PRNG state.
|
|
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 CSPRNG output.
|
|
This function will not normally be needed, as RAND_poll() should have been
|
|
configured to do the appropriate seeding for the local platform.
|
|
Applications that need to keep random state in an external file should
|
|
use L<RAND_load_file(3)>.
|
|
|
|
RAND_seed() is equivalent to RAND_add() with B<randomness> set to B<num>.
|
|
|
|
RAND_event() and RAND_screen() are equivalent to RAND_poll().
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
RAND_status() returns 1 if the CSPRNG 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 HISTORY
|
|
|
|
RAND_event() and RAND_screen() were deprecated in OpenSSL 1.1.0 and should
|
|
not be used.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<RAND_bytes(3)>, L<RAND_egd(3)>,
|
|
L<RAND_load_file(3)>
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2000-2017 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
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|