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1075139c P |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | CRYPTO_memcmp - Constant time memory comparison | |
6 | ||
7 | =head1 SYNOPSIS | |
8 | ||
9 | #include <openssl/crypto.h> | |
10 | ||
11 | int CRYPTO_memcmp(const void *a, const void *b, size_t len); | |
12 | ||
13 | =head1 DESCRIPTION | |
14 | ||
15 | The CRYPTO_memcmp function compares the B<len> bytes pointed to by B<a> and B<b> | |
16 | for equality. | |
17 | It takes an amount of time dependent on B<len>, but independent of the | |
18 | contents of the memory regions pointed to by B<a> and B<b>. | |
19 | ||
20 | =head1 RETURN VALUES | |
21 | ||
22 | CRYPTO_memcmp() returns 0 if the memory regions are equal and non-zero | |
23 | otherwise. | |
24 | ||
25 | =head1 NOTES | |
26 | ||
27 | Unlike memcmp(2), this function cannot be used to order the two memory regions | |
28 | as the return value when they differ is undefined, other than being non-zero. | |
29 | ||
30 | =head1 COPYRIGHT | |
31 | ||
32 | Copyright 2019 The OpenSSL Project Authors. All Rights Reserved. | |
33 | ||
34 | Licensed under the Apache License 2.0 (the "License"). You may not use | |
35 | this file except in compliance with the License. You can obtain a copy | |
36 | in the file LICENSE in the source distribution or at | |
37 | L<https://www.openssl.org/source/license.html>. | |
38 | ||
39 | =cut |