1 files changed, 49 insertions, 0 deletions
diff --git a/Core/Util/StringUtils.php b/Core/Util/StringUtils.php
new file mode 100644
index 0000000..d21efd3
--- /dev/null
+++ b/Core/Util/StringUtils.php
@@ -0,0 +1,49 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Security\Core\Util;
+
+/**
+ * String utility functions.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class StringUtils
+{
+    /**
+     * This class should not be instantiated
+     */
+    private function __construct() {}
+
+    /**
+     * Compares two strings.
+     *
+     * This method implements a constant-time algorithm to compare strings.
+     *
+     * @param string $str1 The first string
+     * @param string $str2 The second string
+     *
+     * @return Boolean true if the two strings are the same, false otherwise
+     */
+    public static function equals($str1, $str2)
+    {
+        if (strlen($str1) !== $c = strlen($str2)) {
+            return false;
+        }
+
+        $result = 0;
+        for ($i = 0; $i < $c; $i++) {
+            $result |= ord($str1[$i]) ^ ord($str2[$i]);
+        }
+
+        return 0 === $result;
+    }
+}