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Commit | Line | Data |
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dd8dec69 UM |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
b26befb5 NT |
5 | BN_rand, BN_priv_rand, BN_pseudo_rand, |
6 | BN_rand_range, BN_priv_rand_range, BN_pseudo_rand_range | |
7 | - generate pseudo-random number | |
dd8dec69 UM |
8 | |
9 | =head1 SYNOPSIS | |
10 | ||
11 | #include <openssl/bn.h> | |
12 | ||
13 | int BN_rand(BIGNUM *rnd, int bits, int top, int bottom); | |
14 | ||
b26befb5 NT |
15 | int BN_priv_rand(BIGNUM *rnd, int bits, int top, int bottom); |
16 | ||
4d524e10 | 17 | int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom); |
38e33cef | 18 | |
e3068929 | 19 | int BN_rand_range(BIGNUM *rnd, BIGNUM *range); |
57e7d3ce | 20 | |
b26befb5 NT |
21 | int BN_priv_rand_range(BIGNUM *rnd, BIGNUM *range); |
22 | ||
b49053ca | 23 | int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range); |
983495c4 | 24 | |
dd8dec69 UM |
25 | =head1 DESCRIPTION |
26 | ||
27 | BN_rand() generates a cryptographically strong pseudo-random number of | |
f67cbb74 | 28 | B<bits> in length and stores it in B<rnd>. |
01c09f9f | 29 | If B<bits> is less than zero, or too small to |
69687aa8 | 30 | accommodate the requirements specified by the B<top> and B<bottom> |
01c09f9f | 31 | parameters, an error is returned. |
f67cbb74 RS |
32 | The B<top> parameters specifies |
33 | requirements on the most significant bit of the generated number. | |
34 | If it is B<BN_RAND_TOP_ANY>, there is no constraint. | |
35 | If it is B<BN_RAND_TOP_ONE>, the top bit must be one. | |
36 | If it is B<BN_RAND_TOP_TWO>, the two most significant bits of | |
335c4f09 | 37 | the number will be set to 1, so that the product of two such random |
f67cbb74 RS |
38 | numbers will always have 2*B<bits> length. |
39 | If B<bottom> is B<BN_RAND_BOTTOM_ODD>, the number will be odd; if it | |
40 | is B<BN_RAND_BOTTOM_ANY> it can be odd or even. | |
41 | If B<bits> is 1 then B<top> cannot also be B<BN_RAND_FLG_TOPTWO>. | |
dd8dec69 | 42 | |
57e7d3ce | 43 | BN_rand_range() generates a cryptographically strong pseudo-random |
31d6c0b2 | 44 | number B<rnd> in the range 0 E<lt>= B<rnd> E<lt> B<range>. |
57e7d3ce | 45 | |
b26befb5 NT |
46 | BN_priv_rand() and BN_priv_rand_range() have the same semantics as |
47 | BN_rand() and BN_rand_range() respectively. They are intended to be | |
48 | used for generating values that should remain private, and mirror the | |
49 | same difference between L<RAND_bytes(3)> and L<RAND_priv_bytes(3)>. | |
50 | ||
51 | =head1 NOTES | |
52 | ||
53 | Always check the error return value of these functions and do not take | |
54 | randomness for granted: an error occurs if the CSPRNG has not been | |
55 | seeded with enough randomness to ensure an unpredictable byte sequence. | |
dd8dec69 UM |
56 | |
57 | =head1 RETURN VALUES | |
58 | ||
57e7d3ce | 59 | The functions return 1 on success, 0 on error. |
9b86974e | 60 | The error codes can be obtained by L<ERR_get_error(3)>. |
dd8dec69 | 61 | |
b5c4bbbe JL |
62 | =head1 SEE ALSO |
63 | ||
64 | L<ERR_get_error(3)>, | |
65 | L<RAND_add(3)>, | |
66 | L<RAND_bytes(3)>, | |
67 | L<RAND_priv_bytes(3)>, | |
68 | L<RAND(7)>, | |
69 | L<RAND_DRBG(7)> | |
70 | ||
5ecff87d RS |
71 | =head1 HISTORY |
72 | ||
b26befb5 NT |
73 | =over 2 |
74 | ||
75 | =item * | |
76 | ||
77 | Starting with OpenSSL release 1.1.0, BN_pseudo_rand() has been identical | |
78 | to BN_rand() and BN_pseudo_rand_range() has been identical to | |
79 | BN_rand_range(). | |
5ecff87d RS |
80 | The "pseudo" functions should not be used and may be deprecated in |
81 | a future release. | |
82 | ||
b26befb5 NT |
83 | =item * |
84 | ||
fc5ecadd DMSP |
85 | The |
86 | BN_priv_rand() and BN_priv_rand_range() functions were added in OpenSSL 1.1.1. | |
b26befb5 NT |
87 | |
88 | =back | |
89 | ||
e2f92610 RS |
90 | =head1 COPYRIGHT |
91 | ||
b5c4bbbe | 92 | Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 | 93 | |
4746f25a | 94 | Licensed under the Apache License 2.0 (the "License"). You may not use |
e2f92610 RS |
95 | this file except in compliance with the License. You can obtain a copy |
96 | in the file LICENSE in the source distribution or at | |
97 | L<https://www.openssl.org/source/license.html>. | |
98 | ||
99 | =cut |