| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 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 nonzero |
| 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 nonzero. |
| 29 | |
| 30 | =head1 COPYRIGHT |
| 31 | |
| 32 | Copyright 2019-2020 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 |