diff --git a/phpseclib/Common/Functions/Strings.php b/phpseclib/Common/Functions/Strings.php
index 9e265d09..2f6ccb7e 100644
--- a/phpseclib/Common/Functions/Strings.php
+++ b/phpseclib/Common/Functions/Strings.php
@@ -60,35 +60,6 @@ abstract class Strings
         return $substr;
     }
 
-    /**
-     * Performs blinded equality testing on strings
-     *
-     * Protects against a particular type of timing attack described.
-     *
-     * See {@link http://codahale.com/a-lesson-in-timing-attacks/ A Lesson In Timing Attacks (or, Don't use MessageDigest.isEquals)}
-     *
-     * Thanks for the heads up singpolyma!
-     *
-     * @access public
-     * @param string $x
-     * @param string $y
-     * @return bool
-     */
-    public static function equals($x, $y)
-    {
-        if (strlen($x) != strlen($y)) {
-            return false;
-        }
-
-        $result = "\0";
-        $x^= $y;
-        for ($i = 0; $i < strlen($x); $i++) {
-            $result|= $x[$i];
-        }
-
-        return $result === "\0";
-    }
-
     /**
      * Parse SSH2-style string
      *
diff --git a/phpseclib/Crypt/Common/Keys/PuTTY.php b/phpseclib/Crypt/Common/Keys/PuTTY.php
index ba223697..0371552c 100644
--- a/phpseclib/Crypt/Common/Keys/PuTTY.php
+++ b/phpseclib/Crypt/Common/Keys/PuTTY.php
@@ -155,7 +155,7 @@ abstract class PuTTY
         $hmac = trim(preg_replace('#Private-MAC: (.+)#', '$1', $key[$publicLength + $privateLength + 5]));
         $hmac = Hex::decode($hmac);
 
-        if (!Strings::equals($hash->hash($source), $hmac)) {
+        if (!hash_equals($hash->hash($source), $hmac)) {
             throw new \UnexpectedValueException('MAC validation error');
         }
 
diff --git a/phpseclib/Crypt/RSA.php b/phpseclib/Crypt/RSA.php
index 21f1bfaf..7dd637b7 100644
--- a/phpseclib/Crypt/RSA.php
+++ b/phpseclib/Crypt/RSA.php
@@ -1236,7 +1236,7 @@ class RSA extends AsymmetricKey
         $db = $maskedDB ^ $dbMask;
         $lHash2 = substr($db, 0, $this->hLen);
         $m = substr($db, $this->hLen);
-        $hashesMatch = Strings::equals($lHash, $lHash2);
+        $hashesMatch = hash_equals($lHash, $lHash2);
         $leadingZeros = 1;
         $patternMatch = 0;
         $offset = 0;
@@ -1463,7 +1463,7 @@ class RSA extends AsymmetricKey
         $salt = substr($db, $temp + 1); // should be $sLen long
         $m2 = "\0\0\0\0\0\0\0\0" . $mHash . $salt;
         $h2 = $this->hash->hash($m2);
-        return Strings::equals($h, $h2);
+        return hash_equals($h, $h2);
     }
 
     /**
@@ -1657,7 +1657,7 @@ class RSA extends AsymmetricKey
         }
 
         // Compare
-        return Strings::equals($em, $em2);
+        return hash_equals($em, $em2);
     }
 
     /**
@@ -1747,7 +1747,7 @@ class RSA extends AsymmetricKey
         $em = $hash->hash($m);
         $em2 = $decoded['digest'];
 
-        return Strings::equals($em, $em2);
+        return hash_equals($em, $em2);
     }
 
     /**