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+=pod
+
+=head1 NAME
+
+BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - generate pseudo-random number
+
+=head1 SYNOPSIS
+
+ #include <openssl/bn.h>
+
+ int BN_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_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>.
+If B<bits> is less than zero, or too small to
+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.
+If it is B<BN_RAND_TOP_ANY>, there is no constraint.
+If it is B<BN_RAND_TOP_ONE>, the top bit must be one.
+If it is B<BN_RAND_TOP_TWO>, the two most significant bits of
+the number will be set to 1, so that the product of two such random
+numbers will always have 2*B<bits> length.
+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_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.
+
+The PRNG must be seeded prior to calling BN_rand() or BN_rand_range().
+
+=head1 RETURN VALUES
+
+The functions return 1 on success, 0 on error.
+The error codes can be obtained by L<ERR_get_error(3)>.
+
+=head1 SEE ALSO
+
+L<ERR_get_error(3)>, L<RAND_add(3)>, L<RAND_bytes(3)>
+
+=head1 COPYRIGHT
+
+Copyright 2000-2017 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
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut