diff --git a/phpseclib/Net/SSH2.php b/phpseclib/Net/SSH2.php
index 5011629d..fc49f0cb 100644
--- a/phpseclib/Net/SSH2.php
+++ b/phpseclib/Net/SSH2.php
@@ -112,6 +112,13 @@ if (!class_exists('Crypt_AES')) {
     require_once('Crypt/AES.php');
 }
 
+/**
+ * Include Crypt_Twofish
+ */
+if (!class_exists('Crypt_Twofish')) {
+    require_once('Crypt/Twofish.php');
+}
+
 /**#@+
  * Execution Bitmap Masks
  *
@@ -966,24 +973,36 @@ class Net_SSH2 {
         );
 
         static $encryption_algorithms = array(
+/*
             // from <http://tools.ietf.org/html/rfc4345#section-4>:
             'arcfour256',
             'arcfour128',
 
-            'arcfour',    // OPTIONAL          the ARCFOUR stream cipher with a 128-bit key
+            'arcfour',        // OPTIONAL          the ARCFOUR stream cipher with a 128-bit key
 
-            'aes128-cbc', // RECOMMENDED       AES with a 128-bit key
-            'aes192-cbc', // OPTIONAL          AES with a 192-bit key
-            'aes256-cbc', // OPTIONAL          AES in CBC mode, with a 256-bit key
+            // CTR modes from <http://tools.ietf.org/html/rfc4344#section-4>:
+            'aes128-ctr',     // RECOMMENDED       AES (Rijndael) in SDCTR mode, with 128-bit key
+            'aes192-ctr',     // RECOMMENDED       AES with 192-bit key
+            'aes256-ctr',     // RECOMMENDED       AES with 256-bit key
 
-            // from <http://tools.ietf.org/html/rfc4344#section-4>:
-            'aes128-ctr', // RECOMMENDED       AES (Rijndael) in SDCTR mode, with 128-bit key
-            'aes192-ctr', // RECOMMENDED       AES with 192-bit key
-            'aes256-ctr', // RECOMMENDED       AES with 256-bit key
-            '3des-ctr',   // RECOMMENDED       Three-key 3DES in SDCTR mode
+            'twofish128-ctr', // OPTIONAL          Twofish in SDCTR mode, with 128-bit key
+            'twofish192-ctr', // OPTIONAL          Twofish with 192-bit key
+            'twofish256-ctr', // OPTIONAL          Twofish with 256-bit key
 
-            '3des-cbc',   // REQUIRED          three-key 3DES in CBC mode
-            'none'        // OPTIONAL          no encryption; NOT RECOMMENDED
+            'aes128-cbc',     // RECOMMENDED       AES with a 128-bit key
+            'aes192-cbc',     // OPTIONAL          AES with a 192-bit key
+            'aes256-cbc',     // OPTIONAL          AES in CBC mode, with a 256-bit key
+*/
+
+            'twofish128-cbc', // OPTIONAL          Twofish with a 128-bit key
+            'twofish192-cbc', // OPTIONAL          Twofish with a 192-bit key
+            'twofish256-cbc',
+            'twofish-cbc',    // OPTIONAL          alias for "twofish256-cbc"
+                              //                   (this is being retained for historical reasons)
+            '3des-ctr',       // RECOMMENDED       Three-key 3DES in SDCTR mode
+
+            '3des-cbc',       // REQUIRED          three-key 3DES in CBC mode
+            'none'            // OPTIONAL          no encryption; NOT RECOMMENDED
         );
 
         static $mac_algorithms = array(
@@ -1092,14 +1111,21 @@ class Net_SSH2 {
                 break;
             case 'aes256-cbc':
             case 'aes256-ctr':
+            case 'twofish-cbc':
+            case 'twofish256-cbc':
+            case 'twofish256-ctr':
                 $decryptKeyLength = 32; // eg. 256 / 8
                 break;
             case 'aes192-cbc':
             case 'aes192-ctr':
+            case 'twofish192-cbc':
+            case 'twofish192-ctr':
                 $decryptKeyLength = 24; // eg. 192 / 8
                 break;
             case 'aes128-cbc':
             case 'aes128-ctr':
+            case 'twofish128-cbc':
+            case 'twofish128-ctr':
                 $decryptKeyLength = 16; // eg. 128 / 8
                 break;
             case 'arcfour':
@@ -1123,14 +1149,21 @@ class Net_SSH2 {
         switch ($encrypt) {
             case '3des-cbc':
             case '3des-ctr':
+            case 'twofish-cbc':
+            case 'twofish256-cbc':
+            case 'twofish256-ctr':
                 $encryptKeyLength = 24;
                 break;
             case 'aes256-cbc':
             case 'aes256-ctr':
+            case 'twofish192-cbc':
+            case 'twofish192-ctr':
                 $encryptKeyLength = 32;
                 break;
             case 'aes192-cbc':
             case 'aes192-ctr':
+            case 'twofish128-cbc':
+            case 'twofish128-ctr':
                 $encryptKeyLength = 24;
                 break;
             case 'aes128-cbc':
@@ -1307,6 +1340,19 @@ class Net_SSH2 {
                 $this->encrypt = new Crypt_AES(CRYPT_AES_MODE_CTR);
                 $this->encrypt_block_size = 16; // eg. 128 / 8
                 break;
+            case 'twofish128-cbc':
+            case 'twofish192-cbc':
+            case 'twofish256-cbc':
+            case 'twofish-cbc':
+                $this->encrypt = new Crypt_Twofish();
+                $this->decrypt_block_size = 16;
+                break;
+            case 'twofish128-ctr':
+            case 'twofish192-ctr':
+            case 'twofish256-ctr':
+                $this->encrypt = new Crypt_Twofish(CRYPT_TWOFISH_MODE_CTR);
+                $this->decrypt_block_size = 16;
+                break;
             case 'arcfour':
             case 'arcfour128':
             case 'arcfour256':
@@ -1335,6 +1381,19 @@ class Net_SSH2 {
                 $this->decrypt = new Crypt_AES(CRYPT_AES_MODE_CTR);
                 $this->decrypt_block_size = 16;
                 break;
+            case 'twofish128-cbc':
+            case 'twofish192-cbc':
+            case 'twofish256-cbc':
+            case 'twofish-cbc':
+                $this->decrypt = new Crypt_Twofish();
+                $this->decrypt_block_size = 16;
+                break;
+            case 'twofish128-ctr':
+            case 'twofish192-ctr':
+            case 'twofish256-ctr':
+                $this->decrypt = new Crypt_Twofish(CRYPT_TWOFISH_MODE_CTR);
+                $this->decrypt_block_size = 16;
+                break;
             case 'arcfour':
             case 'arcfour128':
             case 'arcfour256':
@@ -3223,4 +3282,4 @@ class Net_SSH2 {
         }
         return $this->exit_status;
     }
-}
+}
\ No newline at end of file