| =pod |
| |
| =head1 NAME |
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| BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - generate pseudo-random number |
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| =head1 SYNOPSIS |
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| #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); |
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| int BN_rand_range(BIGNUM *rnd, BIGNUM *range); |
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| int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range); |
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| =head1 DESCRIPTION |
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| 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_rand_range() generates a cryptographically strong pseudo-random |
| number B<rnd> in the range 0 E<lt>= B<rnd> E<lt> B<range>. |
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| The PRNG must be seeded prior to calling BN_rand() or BN_rand_range(). |
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| =head1 RETURN VALUES |
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| The functions return 1 on success, 0 on error. |
| The error codes can be obtained by L<ERR_get_error(3)>. |
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| =head1 HISTORY |
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| 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. |
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| =head1 SEE ALSO |
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| L<ERR_get_error(3)>, L<RAND_add(3)>, L<RAND_bytes(3)> |
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| =head1 COPYRIGHT |
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| Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved. |
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| 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 |
