From 3cdf6d45936b29b4a412b94a599a93f6e181f210 Mon Sep 17 00:00:00 2001
From: "palmer@chromium.org"
 <palmer@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>
Date: Fri, 7 Oct 2011 17:02:48 +0000
Subject: Make constant-time comparison operators for cryptographic uses
 public.

Review URL: http://codereview.chromium.org/8124011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@104502 0039d316-1c4b-4281-b951-d872f2087c98
---
 crypto/secure_util.cc | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 crypto/secure_util.cc

(limited to 'crypto/secure_util.cc')

diff --git a/crypto/secure_util.cc b/crypto/secure_util.cc
new file mode 100644
index 0000000..3fe8aa9
--- /dev/null
+++ b/crypto/secure_util.cc
@@ -0,0 +1,19 @@
+// Copyright (c) 2011 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.
+
+#include "crypto/secure_util.h"
+
+namespace crypto {
+
+bool SecureMemEqual(const void* s1, const void* s2, size_t n) {
+  const unsigned char* s1_ptr = reinterpret_cast<const unsigned char*>(s1);
+  const unsigned char* s2_ptr = reinterpret_cast<const unsigned char*>(s2);
+  unsigned char tmp = 0;
+  for (size_t i = 0; i < n; ++i, ++s1_ptr, ++s2_ptr)
+    tmp |= *s1_ptr ^ *s2_ptr;
+  return (tmp == 0);
+}
+
+}  // namespace crypto
+
-- 
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