1RAND_SET_RAND_METHOD(3)             OpenSSL            RAND_SET_RAND_METHOD(3)
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NAME

6       RAND_set_rand_method, RAND_get_rand_method, RAND_OpenSSL - select RAND
7       method
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SYNOPSIS

10        #include <openssl/rand.h>
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12        RAND_METHOD *RAND_OpenSSL(void);
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14        int RAND_set_rand_method(const RAND_METHOD *meth);
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16        const RAND_METHOD *RAND_get_rand_method(void);
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DESCRIPTION

19       A RAND_METHOD specifies the functions that OpenSSL uses for random
20       number generation.
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22       RAND_OpenSSL() returns the default RAND_METHOD implementation by
23       OpenSSL.  This implementation ensures that the PRNG state is unique for
24       each thread.
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26       If an ENGINE is loaded that provides the RAND API, however, it will be
27       used instead of the method returned by RAND_OpenSSL().
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29       RAND_set_rand_method() makes meth the method for PRNG use.  If an
30       ENGINE was providing the method, it will be released first.
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32       RAND_get_rand_method() returns a pointer to the current RAND_METHOD.
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THE RAND_METHOD STRUCTURE

35        typedef struct rand_meth_st {
36            int (*seed)(const void *buf, int num);
37            int (*bytes)(unsigned char *buf, int num);
38            void (*cleanup)(void);
39            int (*add)(const void *buf, int num, double entropy);
40            int (*pseudorand)(unsigned char *buf, int num);
41            int (*status)(void);
42        } RAND_METHOD;
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44       The fields point to functions that are used by, in order, RAND_seed(),
45       RAND_bytes(), internal RAND cleanup, RAND_add(), RAND_pseudo_rand() and
46       RAND_status().  Each pointer may be NULL if the function is not
47       implemented.
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RETURN VALUES

50       RAND_set_rand_method() returns 1 on success and 0 on failure.
51       RAND_get_rand_method() and RAND_OpenSSL() return pointers to the
52       respective methods.
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SEE ALSO

55       RAND_bytes(3), ENGINE_by_id(3), RAND(7)
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58       Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
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60       Licensed under the OpenSSL license (the "License").  You may not use
61       this file except in compliance with the License.  You can obtain a copy
62       in the file LICENSE in the source distribution or at
63       <https://www.openssl.org/source/license.html>.
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671.1.1g                            2020-04-23           RAND_SET_RAND_METHOD(3)
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