=head1 NAME
-BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - generate pseudo-random number
+BN_rand, BN_priv_rand, BN_pseudo_rand,
+BN_rand_range, BN_priv_rand_range, BN_pseudo_rand_range
+- generate pseudo-random number
=head1 SYNOPSIS
int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
+ int BN_priv_rand(BIGNUM *rnd, int bits, int top, int bottom);
+
int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
int BN_rand_range(BIGNUM *rnd, BIGNUM *range);
+ int BN_priv_rand_range(BIGNUM *rnd, BIGNUM *range);
+
int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range);
=head1 DESCRIPTION
BN_rand_range() generates a cryptographically strong pseudo-random
number B<rnd> in the range 0 E<lt>= B<rnd> E<lt> B<range>.
-The PRNG must be seeded prior to calling BN_rand() or BN_rand_range().
+BN_priv_rand() and BN_priv_rand_range() have the same semantics as
+BN_rand() and BN_rand_range() respectively. They are intended to be
+used for generating values that should remain private, and mirror the
+same difference between L<RAND_bytes(3)> and L<RAND_priv_bytes(3)>.
+
+=head1 NOTES
+
+Always check the error return value of these functions and do not take
+randomness for granted: an error occurs if the CSPRNG has not been
+seeded with enough randomness to ensure an unpredictable byte sequence.
=head1 RETURN VALUES
=head1 HISTORY
-Starting with OpenSSL release 1.1.0,
-BN_pseudo_rand() has been identical to BN_rand()
-and
-BN_pseudo_rand_range() has been identical to BN_rand_range().
+=over 2
+
+=item *
+
+Starting with OpenSSL release 1.1.0, BN_pseudo_rand() has been identical
+to BN_rand() and BN_pseudo_rand_range() has been identical to
+BN_rand_range().
The "pseudo" functions should not be used and may be deprecated in
a future release.
+=item *
+
+BN_priv_rand() and BN_priv_rand_range() were added in OpenSSL 1.1.1.
+
+=back
+
=head1 SEE ALSO
-L<ERR_get_error(3)>, L<RAND_add(3)>, L<RAND_bytes(3)>
+L<ERR_get_error(3)>,
+L<RAND_add(3)>,
+L<RAND_bytes(3)>,
+L<RAND_priv_bytes(3)>,
+L<RAND(7)>,
+L<RAND_DRBG(7)>
=head1 COPYRIGHT
-Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2018 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
=head1 DESCRIPTION
RAND_bytes() puts B<num> cryptographically strong pseudo-random bytes
-into B<buf>. An error occurs if the CSPRNG has not been seeded with
-enough randomness to ensure an unpredictable byte sequence.
+into B<buf>.
RAND_priv_bytes() has the same semantics as RAND_bytes(). It is intended to
-be used for generating long-term private keys. If using the default
-RAND_METHOD, this function uses a separate instance of the PRNG so that
-a compromise of the global generator will not affect such key generation.
+be used for generating values that should remain private. If using the
+default RAND_METHOD, this function uses a separate "private" PRNG
+instance so that a compromise of the "public" PRNG instance will not
+affect the secrecy of these private values, as described in L<RAND(7)>
+and L<RAND_DRBG(7)>.
+
+=head1 NOTES
+
+Always check the error return value of RAND_bytes() and
+RAND_priv_bytes() and do not take randomness for granted: an error occurs
+if the CSPRNG has not been seeded with enough randomness to ensure an
+unpredictable byte sequence.
=head1 RETURN VALUES
=head1 HISTORY
+=over 2
+
+=item *
+
RAND_pseudo_bytes() was deprecated in OpenSSL 1.1.0; use RAND_bytes() instead.
+=item *
+
+RAND_priv_bytes() was added in OpenSSL 1.1.1.
+
+=back
+
=head1 SEE ALSO
L<RAND_add(3)>,
L<RAND_bytes(3)>,
+L<RAND_priv_bytes(3)>,
L<ERR_get_error(3)>,
-L<RAND(7)>
+L<RAND(7)>,
+L<RAND_DRBG(7)>
=head1 COPYRIGHT
It seeds and reseeds itself automatically using trusted random sources
provided by the operating system.
-As a normal application developer, you don't have to worry about any details,
+As a normal application developer, you do not have to worry about any details,
just use L<RAND_bytes(3)> to obtain random data.
Having said that, there is one important rule to obey: Always check the error
-return value of L<RAND_bytes(3)> and don't take randomness for granted.
+return value of L<RAND_bytes(3)> and do not take randomness for granted.
-For long-term secrets, you can use L<RAND_priv_bytes(3)> instead.
+For values that should remain secret, you can use L<RAND_priv_bytes(3)>
+instead.
This method does not provide 'better' randomness, it uses the same type of CSPRNG.
-The intention behind using a dedicated CSPRNG exclusively for long-term secrets is
-that none of its output should be visible to an attacker (e.g used as salt value),
-in order to reveal as little information as possible about its internal state.
+The intention behind using a dedicated CSPRNG exclusively for private
+values is that none of its output should be visible to an attacker (e.g.,
+used as salt value), in order to reveal as little information as
+possible about its internal state, and that a compromise of the "public"
+CSPRNG instance will not affect the secrecy of these private values.
In the rare case where the default implementation does not satisfy your special
requirements, there are two options:
L<RAND_add(3)>,
L<RAND_bytes(3)>,
L<RAND_priv_bytes(3)>,
-L<RAND_get_rand_method(3)>
-L<RAND_set_rand_method(3)>
+L<RAND_get_rand_method(3)>,
+L<RAND_set_rand_method(3)>,
L<RAND_OpenSSL(3)>,
-L<RAND_DRBG(7)>,
+L<RAND_DRBG(7)>
=head1 COPYRIGHT
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