| =pod |
| |
| =head1 NAME |
| |
| 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, |
| unsigned int strength, 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, |
| unsigned int strength, BN_CTX *ctx); |
| int BN_priv_rand(BIGNUM *rnd, int bits, int top, int bottom); |
| |
| int BN_rand_range_ex(BIGNUM *rnd, const BIGNUM *range, unsigned int strength, |
| BN_CTX *ctx); |
| int BN_rand_range(BIGNUM *rnd, const BIGNUM *range); |
| |
| int BN_priv_rand_range_ex(BIGNUM *rnd, const BIGNUM *range, unsigned int strength, |
| BN_CTX *ctx); |
| int BN_priv_rand_range(BIGNUM *rnd, const BIGNUM *range); |
| |
| The following functions have been deprecated since OpenSSL 3.0, and can be |
| hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, |
| see L<openssl_user_macros(7)>: |
| |
| int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom); |
| int BN_pseudo_rand_range(BIGNUM *rnd, const BIGNUM *range); |
| |
| =head1 DESCRIPTION |
| |
| BN_rand_ex() generates a cryptographically strong pseudo-random |
| number of I<bits> in length and security strength at least I<strength> bits |
| using the random number generator for the library context associated with |
| I<ctx>. The function stores the generated data in I<rnd>. The parameter I<ctx> |
| may be NULL in which case the default library context is used. |
| If I<bits> is less than zero, or too small to |
| accommodate the requirements specified by the I<top> and I<bottom> |
| parameters, an error is returned. |
| The I<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*I<bits> length. |
| If I<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 I<bits> is 1 then I<top> cannot also be B<BN_RAND_TOP_TWO>. |
| |
| 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 I<rnd>, of security strength at least I<strength> bits, |
| in the range 0 E<lt>= I<rnd> E<lt> I<range> using the random number |
| generator for the library context associated with I<ctx>. The parameter I<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_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)>. |
| |
| =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 |
| |
| 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)>, |
| L<RAND_priv_bytes(3)>, |
| L<RAND(7)>, |
| L<EVP_RAND(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 BN_pseudo_rand() and BN_pseudo_rand_range() functions were |
| deprecated in OpenSSL 3.0. |
| |
| =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 2000-2022 The OpenSSL Project Authors. All Rights Reserved. |
| |
| 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>. |
| |
| =cut |