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These were initially added as internal functions only. However they will also need to be used by libssl as well. Therefore it make sense to move them into the public API. Reviewed-by: Richard Levitte <levitte@openssl.org> (Merged from https://github.com/openssl/openssl/pull/10864)
96 lines
2.7 KiB
Plaintext
96 lines
2.7 KiB
Plaintext
=pod
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=head1 NAME
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RAND_bytes, RAND_priv_bytes, RAND_bytes_ex, RAND_priv_bytes_ex,
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RAND_pseudo_bytes - generate random data
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=head1 SYNOPSIS
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#include <openssl/rand.h>
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int RAND_bytes(unsigned char *buf, int num);
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int RAND_priv_bytes(unsigned char *buf, int num);
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int RAND_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num);
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int RAND_priv_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num);
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Deprecated since OpenSSL 1.1.0, can be hidden entirely by defining
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B<OPENSSL_API_COMPAT> with a suitable version value, see
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L<openssl_user_macros(7)>:
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int RAND_pseudo_bytes(unsigned char *buf, int num);
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=head1 DESCRIPTION
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RAND_bytes() puts B<num> cryptographically strong pseudo-random bytes
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into B<buf>.
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RAND_priv_bytes() has the same semantics as RAND_bytes(). It is intended to
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be used for generating values that should remain private. If using the
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default RAND_METHOD, this function uses a separate "private" PRNG
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instance so that a compromise of the "public" PRNG instance will not
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affect the secrecy of these private values, as described in L<RAND(7)>
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and L<RAND_DRBG(7)>.
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RAND_bytes_ex() and RAND_priv_bytes_ex() are the same as RAND_bytes() and
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RAND_priv_bytes() except that they both take an additional I<ctx> parameter.
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The DRBG used for the operation is the public or private DRBG associated with
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the specified I<ctx>. The parameter can be NULL, in which case
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the default library context is used (see L<OPENSSL_CTX(3)>.
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If the default RAND_METHOD has been changed then for compatibility reasons the
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RAND_METHOD will be used in preference and the DRBG of the library context
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ignored.
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=head1 NOTES
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Always check the error return value of RAND_bytes() and
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RAND_priv_bytes() and do not take randomness for granted: an error occurs
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if the CSPRNG has not been seeded with enough randomness to ensure an
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unpredictable byte sequence.
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=head1 RETURN VALUES
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RAND_bytes() and RAND_priv_bytes()
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return 1 on success, -1 if not supported by the current
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RAND method, or 0 on other failure. The error code can be
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obtained by L<ERR_get_error(3)>.
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=head1 SEE ALSO
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L<RAND_add(3)>,
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L<RAND_bytes(3)>,
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L<RAND_priv_bytes(3)>,
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L<ERR_get_error(3)>,
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L<RAND(7)>,
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L<RAND_DRBG(7)>
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=head1 HISTORY
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=over 2
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=item *
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RAND_pseudo_bytes() was deprecated in OpenSSL 1.1.0; use RAND_bytes() instead.
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=item *
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The RAND_priv_bytes() function was added in OpenSSL 1.1.1.
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=item *
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The RAND_bytes_ex() and RAND_priv_bytes_ex() functions were added in OpenSSL 3.0
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=back
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=head1 COPYRIGHT
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Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the Apache License 2.0 (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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