| // Copyright 2012 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef CRYPTO_SECURE_UTIL_H_ |
| #define CRYPTO_SECURE_UTIL_H_ |
| |
| #include <stddef.h> |
| |
| #include "crypto/crypto_export.h" |
| |
| namespace crypto { |
| |
| // Performs a constant-time comparison of two strings, returning true if the |
| // strings are equal. |
| // |
| // For cryptographic operations, comparison functions such as memcmp() may |
| // expose side-channel information about input, allowing an attacker to |
| // perform timing analysis to determine what the expected bits should be. In |
| // order to avoid such attacks, the comparison must execute in constant time, |
| // so as to not to reveal to the attacker where the difference(s) are. |
| // For an example attack, see |
| // http://groups.google.com/group/keyczar-discuss/browse_thread/thread/5571eca0948b2a13 |
| CRYPTO_EXPORT bool SecureMemEqual(const void* s1, const void* s2, size_t n); |
| |
| } // namespace crypto |
| |
| #endif // CRYPTO_SECURE_UTIL_H_ |
| |
