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- // Copyright (c) 2012 The Chromium Authors. All rights reserved.
- // 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_
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