| [email protected] | cf21188 | 2012-07-11 07:19:14 | [diff] [blame] | 1 | // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| [email protected] | 3cdf6d4 | 2011-10-07 17:02:48 | [diff] [blame] | 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef CRYPTO_SECURE_UTIL_H_ |
| 6 | #define CRYPTO_SECURE_UTIL_H_ |
| [email protected] | 3cdf6d4 | 2011-10-07 17:02:48 | [diff] [blame] | 7 | |
| 8 | #include <stddef.h> |
| 9 | |
| 10 | #include "crypto/crypto_export.h" |
| 11 | |
| 12 | namespace crypto { |
| 13 | |
| 14 | // Performs a constant-time comparison of two strings, returning true if the |
| 15 | // strings are equal. |
| 16 | // |
| 17 | // For cryptographic operations, comparison functions such as memcmp() may |
| 18 | // expose side-channel information about input, allowing an attacker to |
| 19 | // perform timing analysis to determine what the expected bits should be. In |
| 20 | // order to avoid such attacks, the comparison must execute in constant time, |
| 21 | // so as to not to reveal to the attacker where the difference(s) are. |
| 22 | // For an example attack, see |
| 23 | // http://groups.google.com/group/keyczar-discuss/browse_thread/thread/5571eca0948b2a13 |
| 24 | CRYPTO_EXPORT bool SecureMemEqual(const void* s1, const void* s2, size_t n); |
| 25 | |
| 26 | } // namespace crypto |
| 27 | |
| 28 | #endif // CRYPTO_SECURE_UTIL_H_ |
| 29 | |
