OPENSSL_s390xcap.pod: list msa9 facility bit (155)

[openssl.git] / doc / man3 / BN_rand.pod

diff --git a/doc/man3/BN_rand.pod b/doc/man3/BN_rand.pod
index ae15ada7e5a52c3072dcb87757e4f534d453fdbc..fc41322f8e8ffa5db32053c582d21449d6dd1e00 100644 (file)
--- a/doc/man3/BN_rand.pod
+++ b/doc/man3/BN_rand.pod
@@ -2,26 +2,39 @@
 
 =head1 NAME
 
-BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - generate pseudo-random number
+BN_rand_ex, BN_rand, BN_priv_rand_ex, BN_priv_rand, BN_pseudo_rand,
+BN_rand_range_ex, BN_rand_range, BN_priv_rand_range_ex, BN_priv_rand_range,
+BN_pseudo_rand_range
+- generate pseudo-random number
 
 =head1 SYNOPSIS
 
  #include <openssl/bn.h>
 
+ int BN_rand_ex(BIGNUM *rnd, int bits, int top, int bottom, BN_CTX *ctx);
  int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
 
+ int BN_priv_rand_ex(BIGNUM *rnd, int bits, int top, int bottom, BN_CTX *ctx);
+ 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_ex(BIGNUM *rnd, BIGNUM *range, BN_CTX *ctx);
  int BN_rand_range(BIGNUM *rnd, BIGNUM *range);
 
+ int BN_priv_rand_range_ex(BIGNUM *rnd, BIGNUM *range, BN_CTX *ctx);
+ int BN_priv_rand_range(BIGNUM *rnd, BIGNUM *range);
+
  int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range);
 
 =head1 DESCRIPTION
 
-BN_rand() generates a cryptographically strong pseudo-random number of
-B<bits> in length and stores it in B<rnd>.
+BN_rand_ex() generate a cryptographically strong pseudo-random
+number of B<bits> in length and stores it in B<rnd> using the random number
+generator for the library context associated with B<ctx>. The parameter B<ctx>
+may be NULL in which case the default library context is used.
 If B<bits> is less than zero, or too small to
-accomodate the requirements specified by the B<top> and B<bottom>
+accommodate the requirements specified by the B<top> and B<bottom>
 parameters, an error is returned.
 The B<top> parameters specifies
 requirements on the most significant bit of the generated number.
@@ -34,17 +47,28 @@ If B<bottom> is B<BN_RAND_BOTTOM_ODD>, the number will be odd; if it
 is B<BN_RAND_BOTTOM_ANY> it can be odd or even.
 If B<bits> is 1 then B<top> cannot also be B<BN_RAND_FLG_TOPTWO>.
 
-BN_pseudo_rand() does the same, but pseudo-random numbers generated by
-this function are not necessarily unpredictable. They can be used for
-non-cryptographic purposes and for certain purposes in cryptographic
-protocols, but usually not for key generation etc.
+BN_rand() is the same as BN_rand_ex() except that the default library context
+is always used.
+
+BN_rand_range_ex() generates a cryptographically strong pseudo-random
+number B<rnd> in the range 0 E<lt>= B<rnd> E<lt> B<range> using the random number
+generator for the library context associated with B<ctx>. The parameter B<ctx>
+may be NULL in which case the default library context is used.
+
+BN_rand_range() is the same as BN_rand_range_ex() except that the default
+library context is always used.
 
-BN_rand_range() generates a cryptographically strong pseudo-random
-number B<rnd> in the range 0 E<lt>= B<rnd> E<lt> B<range>.
-BN_pseudo_rand_range() does the same, but is based on BN_pseudo_rand(),
-and hence numbers generated by it are not necessarily unpredictable.
+BN_priv_rand_ex(), BN_priv_rand(), BN_priv_rand_rand_ex() and
+BN_priv_rand_range() have the same semantics as BN_rand_ex(), BN_rand(),
+BN_rand_range_ex() 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)>.
 
-The PRNG must be seeded prior to calling BN_rand() or BN_rand_range().
+=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
 
@@ -53,14 +77,42 @@ The error codes can be obtained by L<ERR_get_error(3)>.
 
 =head1 SEE ALSO
 
-L<bn(3)>, L<ERR_get_error(3)>, L<rand(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 HISTORY
+
+=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 *
+
+The
+BN_priv_rand() and BN_priv_rand_range() functions were added in OpenSSL 1.1.1.
+
+=item *
+
+The BN_rand_ex(), BN_priv_rand_ex(), BN_rand_range_ex() and
+BN_priv_rand_range_ex() functions were added in OpenSSL 3.0.
+
+=back
 
 =head1 COPYRIGHT
 
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
 
-Licensed under the OpenSSL license (the "License").  You may not use
+Licensed under the Apache License 2.0 (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>.