f3cd81d653
RAND_cleanup() should not be called expicitly - we should leave auto-deinit to clean this up instead. Reviewed-by: Tim Hudson <tjh@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org>
77 lines
2.3 KiB
Text
77 lines
2.3 KiB
Text
=pod
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=head1 NAME
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rand - pseudo-random number generator
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=head1 SYNOPSIS
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#include <openssl/rand.h>
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int RAND_set_rand_engine(ENGINE *engine);
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int RAND_bytes(unsigned char *buf, int num);
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int RAND_pseudo_bytes(unsigned char *buf, int num);
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void RAND_seed(const void *buf, int num);
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void RAND_add(const void *buf, int num, int entropy);
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int RAND_status(void);
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int RAND_load_file(const char *file, long max_bytes);
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int RAND_write_file(const char *file);
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const char *RAND_file_name(char *file, size_t num);
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int RAND_egd(const char *path);
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void RAND_set_rand_method(const RAND_METHOD *meth);
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const RAND_METHOD *RAND_get_rand_method(void);
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RAND_METHOD *RAND_OpenSSL(void);
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/* For Win32 only */
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void RAND_screen(void);
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int RAND_event(UINT, WPARAM, LPARAM);
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Deprecated:
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#if OPENSSL_API_COMPAT < 0x10100000L
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# define RAND_cleanup()
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#endif
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=head1 DESCRIPTION
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Since the introduction of the ENGINE API, the recommended way of controlling
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default implementations is by using the ENGINE API functions. The default
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B<RAND_METHOD>, as set by RAND_set_rand_method() and returned by
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RAND_get_rand_method(), is only used if no ENGINE has been set as the default
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"rand" implementation. Hence, these two functions are no longer the recommended
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way to control defaults.
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If an alternative B<RAND_METHOD> implementation is being used (either set
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directly or as provided by an ENGINE module), then it is entirely responsible
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for the generation and management of a cryptographically secure PRNG stream. The
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mechanisms described below relate solely to the software PRNG implementation
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built in to OpenSSL and used by default.
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These functions implement a cryptographically secure pseudo-random
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number generator (PRNG). It is used by other library functions for
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example to generate random keys, and applications can use it when they
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need randomness.
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A cryptographic PRNG must be seeded with unpredictable data such as
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mouse movements or keys pressed at random by the user. This is
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described in L<RAND_add(3)>. Its state can be saved in a seed file
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(see L<RAND_load_file(3)>) to avoid having to go through the
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seeding process whenever the application is started.
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L<RAND_bytes(3)> describes how to obtain random data from the
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PRNG.
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=head1 SEE ALSO
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L<BN_rand(3)>, L<RAND_add(3)>,
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L<RAND_load_file(3)>, L<RAND_egd(3)>,
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L<RAND_bytes(3)>,
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L<RAND_set_rand_method(3)>,
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L<RAND_cleanup(3)>
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=cut
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