diff --git a/phpseclib/Crypt/Common/Keys/PKCS1.php b/phpseclib/Crypt/Common/Keys/PKCS1.php
index 7a16f8bd..9b964aad 100644
--- a/phpseclib/Crypt/Common/Keys/PKCS1.php
+++ b/phpseclib/Crypt/Common/Keys/PKCS1.php
@@ -182,7 +182,7 @@ abstract class PKCS1 extends PKCS
      * @param array $options optional
      * @return string
      */
-    protected static function wrapPrivateKey($key, $type, $password, $options = [])
+    protected static function wrapPrivateKey($key, $type, $password, array $options = [])
     {
         if (empty($password) || !is_string($password)) {
             return "-----BEGIN $type PRIVATE KEY-----\r\n" .
diff --git a/phpseclib/Crypt/Common/Keys/PKCS8.php b/phpseclib/Crypt/Common/Keys/PKCS8.php
index 8b3921a7..5c968027 100644
--- a/phpseclib/Crypt/Common/Keys/PKCS8.php
+++ b/phpseclib/Crypt/Common/Keys/PKCS8.php
@@ -529,7 +529,7 @@ abstract class PKCS8 extends PKCS
      * @param array $options optional
      * @return string
      */
-    protected static function wrapPrivateKey($key, $attr, $params, $password, $oid = null, $publicKey = '', $options = [])
+    protected static function wrapPrivateKey($key, $attr, $params, $password, $oid = null, $publicKey = '', array $options = [])
     {
         self::initialize_static_variables();
 
diff --git a/phpseclib/Crypt/Common/Keys/PuTTY.php b/phpseclib/Crypt/Common/Keys/PuTTY.php
index 11159bba..87b6f067 100644
--- a/phpseclib/Crypt/Common/Keys/PuTTY.php
+++ b/phpseclib/Crypt/Common/Keys/PuTTY.php
@@ -175,7 +175,7 @@ abstract class PuTTY
      * @param array $options optional
      * @return string
      */
-    protected static function wrapPrivateKey($public, $private, $type, $password, $options = [])
+    protected static function wrapPrivateKey($public, $private, $type, $password, array $options = [])
     {
         $key = "PuTTY-User-Key-File-2: " . $type . "\r\nEncryption: ";
         $encryption = (!empty($password) || is_string($password)) ? 'aes256-cbc' : 'none';
diff --git a/phpseclib/Crypt/Common/PrivateKey.php b/phpseclib/Crypt/Common/PrivateKey.php
index c726f3ea..4de3c0e7 100644
--- a/phpseclib/Crypt/Common/PrivateKey.php
+++ b/phpseclib/Crypt/Common/PrivateKey.php
@@ -25,6 +25,6 @@ interface PrivateKey
     public function sign($message);
     //public function decrypt($ciphertext);
     public function getPublicKey();
-    public function toString($type);
+    public function toString($type, array $options = []);
     public function withPassword($string);
 }
diff --git a/phpseclib/Crypt/Common/PublicKey.php b/phpseclib/Crypt/Common/PublicKey.php
index c1102f71..1bc3fc3f 100644
--- a/phpseclib/Crypt/Common/PublicKey.php
+++ b/phpseclib/Crypt/Common/PublicKey.php
@@ -24,6 +24,6 @@ interface PublicKey
 {
     public function verify($message, $signature);
     //public function encrypt($plaintext);
-    public function toString($type);
+    public function toString($type, array $options = []);
     public function getFingerprint($algorithm);
 }
diff --git a/phpseclib/Crypt/DSA/Keys/OpenSSH.php b/phpseclib/Crypt/DSA/Keys/OpenSSH.php
index 65a9c417..16b2c453 100644
--- a/phpseclib/Crypt/DSA/Keys/OpenSSH.php
+++ b/phpseclib/Crypt/DSA/Keys/OpenSSH.php
@@ -65,7 +65,7 @@ abstract class OpenSSH extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePublicKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, $options = [])
+    public static function savePublicKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, array $options = [])
     {
         if ($q->getLength() != 160) {
             throw new \InvalidArgumentException('SSH only supports keys with an N (length of Group Order q) of 160');
diff --git a/phpseclib/Crypt/DSA/Keys/PKCS1.php b/phpseclib/Crypt/DSA/Keys/PKCS1.php
index 54e08208..2b028156 100644
--- a/phpseclib/Crypt/DSA/Keys/PKCS1.php
+++ b/phpseclib/Crypt/DSA/Keys/PKCS1.php
@@ -116,7 +116,7 @@ abstract class PKCS1 extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, BigInteger $x, $password = '', $options = [])
+    public static function savePrivateKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, BigInteger $x, $password = '', array $options = [])
     {
         $key = [
             'version' => 0,
diff --git a/phpseclib/Crypt/DSA/Keys/PKCS8.php b/phpseclib/Crypt/DSA/Keys/PKCS8.php
index 661b723c..d4cc8f11 100644
--- a/phpseclib/Crypt/DSA/Keys/PKCS8.php
+++ b/phpseclib/Crypt/DSA/Keys/PKCS8.php
@@ -130,7 +130,7 @@ abstract class PKCS8 extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, BigInteger $x, $password = '', $options = [])
+    public static function savePrivateKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, BigInteger $x, $password = '', array $options = [])
     {
         $params = [
             'p' => $p,
@@ -154,7 +154,7 @@ abstract class PKCS8 extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePublicKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, $options = [])
+    public static function savePublicKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, array $options = [])
     {
         $params = [
             'p' => $p,
diff --git a/phpseclib/Crypt/DSA/Keys/PuTTY.php b/phpseclib/Crypt/DSA/Keys/PuTTY.php
index 03031fb6..04865474 100644
--- a/phpseclib/Crypt/DSA/Keys/PuTTY.php
+++ b/phpseclib/Crypt/DSA/Keys/PuTTY.php
@@ -94,7 +94,7 @@ abstract class PuTTY extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, BigInteger $x, $password = false, $options = [])
+    public static function savePrivateKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, BigInteger $x, $password = false, array $options = [])
     {
         if ($q->getLength() != 160) {
             throw new \InvalidArgumentException('SSH only supports keys with an N (length of Group Order q) of 160');
diff --git a/phpseclib/Crypt/DSA/Parameters.php b/phpseclib/Crypt/DSA/Parameters.php
index b97c1dfe..961473ab 100644
--- a/phpseclib/Crypt/DSA/Parameters.php
+++ b/phpseclib/Crypt/DSA/Parameters.php
@@ -31,7 +31,7 @@ class Parameters extends DSA
      * @param array $options optional
      * @return string
      */
-    public function toString($type = 'PKCS1', $options = [])
+    public function toString($type = 'PKCS1', array $options = [])
     {
         $type = self::validatePlugin('Keys', 'PKCS1', 'saveParameters');
 
diff --git a/phpseclib/Crypt/DSA/PrivateKey.php b/phpseclib/Crypt/DSA/PrivateKey.php
index 32e9fbda..927fe0d7 100644
--- a/phpseclib/Crypt/DSA/PrivateKey.php
+++ b/phpseclib/Crypt/DSA/PrivateKey.php
@@ -147,7 +147,7 @@ class PrivateKey extends DSA implements Common\PrivateKey
      * @param array $options optional
      * @return string
      */
-    public function toString($type, $options = [])
+    public function toString($type, array $options = [])
     {
         $type = self::validatePlugin('Keys', $type, 'savePrivateKey');
 
diff --git a/phpseclib/Crypt/DSA/PublicKey.php b/phpseclib/Crypt/DSA/PublicKey.php
index 72ff5025..37c7c649 100644
--- a/phpseclib/Crypt/DSA/PublicKey.php
+++ b/phpseclib/Crypt/DSA/PublicKey.php
@@ -83,7 +83,7 @@ class PublicKey extends DSA implements Common\PublicKey
      * @param array $options optional
      * @return string
      */
-    public function toString($type, $options = [])
+    public function toString($type, array $options = [])
     {
         $type = self::validatePlugin('Keys', $type, 'savePublicKey');
 
diff --git a/phpseclib/Crypt/ECDSA/Keys/OpenSSH.php b/phpseclib/Crypt/ECDSA/Keys/OpenSSH.php
index c4b07341..8d8f9c1f 100644
--- a/phpseclib/Crypt/ECDSA/Keys/OpenSSH.php
+++ b/phpseclib/Crypt/ECDSA/Keys/OpenSSH.php
@@ -189,7 +189,7 @@ abstract class OpenSSH extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePublicKey(BaseCurve $curve, array $publicKey, $options = [])
+    public static function savePublicKey(BaseCurve $curve, array $publicKey, array $options = [])
     {
         $comment = isset($options['comment']) ? $options['comment'] : self::$comment;
 
diff --git a/phpseclib/Crypt/ECDSA/Keys/PKCS1.php b/phpseclib/Crypt/ECDSA/Keys/PKCS1.php
index c9007b88..7ef60770 100644
--- a/phpseclib/Crypt/ECDSA/Keys/PKCS1.php
+++ b/phpseclib/Crypt/ECDSA/Keys/PKCS1.php
@@ -118,7 +118,7 @@ abstract class PKCS1 extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(Integer $privateKey, BaseCurve $curve, array $publicKey, $password = '', $options = [])
+    public static function savePrivateKey(Integer $privateKey, BaseCurve $curve, array $publicKey, $password = '', array $options = [])
     {
         self::initialize_static_variables();
 
diff --git a/phpseclib/Crypt/ECDSA/Keys/PKCS8.php b/phpseclib/Crypt/ECDSA/Keys/PKCS8.php
index 78b056f5..69ee94db 100644
--- a/phpseclib/Crypt/ECDSA/Keys/PKCS8.php
+++ b/phpseclib/Crypt/ECDSA/Keys/PKCS8.php
@@ -201,7 +201,7 @@ abstract class PKCS8 extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(Integer $privateKey, BaseCurve $curve, array $publicKey, $password = '', $options = [])
+    public static function savePrivateKey(Integer $privateKey, BaseCurve $curve, array $publicKey, $password = '', array $options = [])
     {
         self::initialize_static_variables();
 
diff --git a/phpseclib/Crypt/ECDSA/Keys/PuTTY.php b/phpseclib/Crypt/ECDSA/Keys/PuTTY.php
index eedcc8db..c70a1ce1 100644
--- a/phpseclib/Crypt/ECDSA/Keys/PuTTY.php
+++ b/phpseclib/Crypt/ECDSA/Keys/PuTTY.php
@@ -99,7 +99,7 @@ abstract class PuTTY extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(Integer $privateKey, BaseCurve $curve, array $publicKey, $password = false, $options = [])
+    public static function savePrivateKey(Integer $privateKey, BaseCurve $curve, array $publicKey, $password = false, array $options = [])
     {
         self::initialize_static_variables();
 
diff --git a/phpseclib/Crypt/ECDSA/Parameters.php b/phpseclib/Crypt/ECDSA/Parameters.php
index 03d30261..4d2002e4 100644
--- a/phpseclib/Crypt/ECDSA/Parameters.php
+++ b/phpseclib/Crypt/ECDSA/Parameters.php
@@ -31,7 +31,7 @@ class Parameters extends ECDSA
      * @param array $options optional
      * @return string
      */
-    public function toString($type = 'PKCS1', $options = [])
+    public function toString($type = 'PKCS1', array $options = [])
     {
         $type = self::validatePlugin('Keys', 'PKCS1', 'saveParameters');
 
diff --git a/phpseclib/Crypt/ECDSA/PrivateKey.php b/phpseclib/Crypt/ECDSA/PrivateKey.php
index 82fdf015..e726cc36 100644
--- a/phpseclib/Crypt/ECDSA/PrivateKey.php
+++ b/phpseclib/Crypt/ECDSA/PrivateKey.php
@@ -185,7 +185,7 @@ class PrivateKey extends ECDSA implements Common\PrivateKey
      * @param array $options optional
      * @return string
      */
-    public function toString($type, $options = [])
+    public function toString($type, array $options = [])
     {
         $type = self::validatePlugin('Keys', $type, 'savePrivateKey');
 
diff --git a/phpseclib/Crypt/ECDSA/PublicKey.php b/phpseclib/Crypt/ECDSA/PublicKey.php
index 459c468f..7ae2e183 100644
--- a/phpseclib/Crypt/ECDSA/PublicKey.php
+++ b/phpseclib/Crypt/ECDSA/PublicKey.php
@@ -162,7 +162,7 @@ class PublicKey extends ECDSA implements Common\PublicKey
      * @param array $options optional
      * @return string
      */
-    public function toString($type, $options = [])
+    public function toString($type, array $options = [])
     {
         $type = self::validatePlugin('Keys', $type, 'savePublicKey');
 
diff --git a/phpseclib/Crypt/RSA/Keys/MSBLOB.php b/phpseclib/Crypt/RSA/Keys/MSBLOB.php
index ef4d7ccc..268c2440 100644
--- a/phpseclib/Crypt/RSA/Keys/MSBLOB.php
+++ b/phpseclib/Crypt/RSA/Keys/MSBLOB.php
@@ -185,7 +185,7 @@ abstract class MSBLOB
      * @param string $password optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, $primes, $exponents, $coefficients, $password = '')
+    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, array $primes, array $exponents, array $coefficients, $password = '')
     {
         if (count($primes) != 2) {
             throw new \InvalidArgumentException('MSBLOB does not support multi-prime RSA keys');
diff --git a/phpseclib/Crypt/RSA/Keys/OpenSSH.php b/phpseclib/Crypt/RSA/Keys/OpenSSH.php
index 5df9696e..6d93e5bb 100644
--- a/phpseclib/Crypt/RSA/Keys/OpenSSH.php
+++ b/phpseclib/Crypt/RSA/Keys/OpenSSH.php
@@ -66,7 +66,7 @@ abstract class OpenSSH extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePublicKey(BigInteger $n, BigInteger $e, $options = [])
+    public static function savePublicKey(BigInteger $n, BigInteger $e, array $options = [])
     {
         $RSAPublicKey = Strings::packSSH2('sii', 'ssh-rsa', $e, $n);
 
diff --git a/phpseclib/Crypt/RSA/Keys/PKCS1.php b/phpseclib/Crypt/RSA/Keys/PKCS1.php
index e5152cc1..959bb7dd 100644
--- a/phpseclib/Crypt/RSA/Keys/PKCS1.php
+++ b/phpseclib/Crypt/RSA/Keys/PKCS1.php
@@ -104,7 +104,7 @@ abstract class PKCS1 extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, $primes, $exponents, $coefficients, $password = '', $options = [])
+    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, array $primes, array $exponents, array $coefficients, $password = '', array $options = [])
     {
         $num_primes = count($primes);
         $key = [
diff --git a/phpseclib/Crypt/RSA/Keys/PKCS8.php b/phpseclib/Crypt/RSA/Keys/PKCS8.php
index 1178e93d..5dcbb110 100644
--- a/phpseclib/Crypt/RSA/Keys/PKCS8.php
+++ b/phpseclib/Crypt/RSA/Keys/PKCS8.php
@@ -107,7 +107,7 @@ abstract class PKCS8 extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, $primes, $exponents, $coefficients, $password = '', $options = [])
+    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, array $primes, array $exponents, array $coefficients, $password = '', array $options = [])
     {
         $key = PKCS1::savePrivateKey($n, $e, $d, $primes, $exponents, $coefficients);
         $key = ASN1::extractBER($key);
@@ -123,7 +123,7 @@ abstract class PKCS8 extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePublicKey(BigInteger $n, BigInteger $e, $options = [])
+    public static function savePublicKey(BigInteger $n, BigInteger $e, array $options = [])
     {
         $key = PKCS1::savePublicKey($n, $e);
         $key = ASN1::extractBER($key);
diff --git a/phpseclib/Crypt/RSA/Keys/PSS.php b/phpseclib/Crypt/RSA/Keys/PSS.php
index 2b759984..8795a67d 100644
--- a/phpseclib/Crypt/RSA/Keys/PSS.php
+++ b/phpseclib/Crypt/RSA/Keys/PSS.php
@@ -166,7 +166,7 @@ abstract class PSS extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, $primes, $exponents, $coefficients, $password = '', $options = [])
+    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, array $primes, array $exponents, array $coefficients, $password = '', array $options = [])
     {
         self::initialize_static_variables();
 
@@ -185,7 +185,7 @@ abstract class PSS extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePublicKey(BigInteger $n, BigInteger $e, $options = [])
+    public static function savePublicKey(BigInteger $n, BigInteger $e, array $options = [])
     {
         $key = PKCS1::savePublicKey($n, $e);
         $key = ASN1::extractBER($key);
@@ -200,7 +200,7 @@ abstract class PSS extends Progenitor
      * @param array $options
      * @return string
      */
-    private static function savePSSParams($options)
+    private static function savePSSParams(array $options)
     {
         /*
          The trailerField field is an integer.  It provides
diff --git a/phpseclib/Crypt/RSA/Keys/PuTTY.php b/phpseclib/Crypt/RSA/Keys/PuTTY.php
index 0fa54704..aaef1f98 100644
--- a/phpseclib/Crypt/RSA/Keys/PuTTY.php
+++ b/phpseclib/Crypt/RSA/Keys/PuTTY.php
@@ -103,7 +103,7 @@ abstract class PuTTY extends Progenitor
      * @param array $options optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, $primes, $exponents, $coefficients, $password = '', $options = [])
+    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, array $primes, array $exponents, array $coefficients, $password = '', array $options = [])
     {
         if (count($primes) != 2) {
             throw new \InvalidArgumentException('PuTTY does not support multi-prime RSA keys');
diff --git a/phpseclib/Crypt/RSA/Keys/XML.php b/phpseclib/Crypt/RSA/Keys/XML.php
index 966112bc..06950cc9 100644
--- a/phpseclib/Crypt/RSA/Keys/XML.php
+++ b/phpseclib/Crypt/RSA/Keys/XML.php
@@ -131,7 +131,7 @@ abstract class XML
      * @param string $password optional
      * @return string
      */
-    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, $primes, $exponents, $coefficients, $password = '')
+    public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, array $primes, array $exponents, array $coefficients, $password = '')
     {
         if (count($primes) != 2) {
             throw new \InvalidArgumentException('XML does not support multi-prime RSA keys');
diff --git a/phpseclib/Crypt/RSA/PrivateKey.php b/phpseclib/Crypt/RSA/PrivateKey.php
index 5788f5b5..8810dbdd 100644
--- a/phpseclib/Crypt/RSA/PrivateKey.php
+++ b/phpseclib/Crypt/RSA/PrivateKey.php
@@ -518,7 +518,7 @@ class PrivateKey extends RSA implements Common\PrivateKey
      * @param array $options optional
      * @return string
      */
-    public function toString($type, $options = [])
+    public function toString($type, array $options = [])
     {
         $type = self::validatePlugin(
             'Keys',
diff --git a/phpseclib/Crypt/RSA/PublicKey.php b/phpseclib/Crypt/RSA/PublicKey.php
index 50233633..fe0dff79 100644
--- a/phpseclib/Crypt/RSA/PublicKey.php
+++ b/phpseclib/Crypt/RSA/PublicKey.php
@@ -469,7 +469,7 @@ class PublicKey extends RSA implements Common\PublicKey
      * @param array $options optional
      * @return mixed
      */
-    public function toString($type, $options = [])
+    public function toString($type, array $options = [])
     {
         $type = self::validatePlugin('Keys', $type, 'savePublicKey');
 
diff --git a/phpseclib/System/SSH/Agent/Identity.php b/phpseclib/System/SSH/Agent/Identity.php
index ddba1706..96ddcb56 100644
--- a/phpseclib/System/SSH/Agent/Identity.php
+++ b/phpseclib/System/SSH/Agent/Identity.php
@@ -320,9 +320,10 @@ class Identity implements PrivateKey
      * Returns the private key
      *
      * @param string $type
+     * @param array $options optional
      * @return string
      */
-    public function toString($type)
+    public function toString($type, array $options = [])
     {
         throw new \RuntimeException('ssh-agent does not provide a mechanism to get the private key');
     }