diff --git a/phpseclib/Net/SSH2.php b/phpseclib/Net/SSH2.php
index a335f69c..815b4ed5 100644
--- a/phpseclib/Net/SSH2.php
+++ b/phpseclib/Net/SSH2.php
@@ -156,7 +156,7 @@ class Net_SSH2
      * @var String
      * @access private
      */
-    var $identifier = 'SSH-2.0-phpseclib_0.3';
+    var $identifier;
 
     /**
      * The Socket Object
@@ -919,19 +919,7 @@ class Net_SSH2
             return false;
         }
 
-        $ext = array();
-        if (extension_loaded('mcrypt')) {
-            $ext[] = 'mcrypt';
-        }
-        if (extension_loaded('gmp')) {
-            $ext[] = 'gmp';
-        } else if (extension_loaded('bcmath')) {
-            $ext[] = 'bcmath';
-        }
-
-        if (!empty($ext)) {
-            $this->identifier.= ' (' . implode(', ', $ext) . ')';
-        }
+        $this->identifier = $this->_generate_identifier();
 
         if (defined('NET_SSH2_LOGGING')) {
             $this->_append_log('<-', $extra . $temp);
@@ -968,6 +956,36 @@ class Net_SSH2
         $this->bitmap = NET_SSH2_MASK_CONSTRUCTOR;
     }
 
+    /**
+     * Generates the SSH identifier
+     *
+     * You should overwrite this method in your own class if you want to use another identifier
+     *
+     * @access protected
+     * @return String
+     */
+    function _generate_identifier()
+    {
+        $identifier = 'SSH-2.0-phpseclib_0.3';
+
+        $ext = array();
+        if (extension_loaded('mcrypt')) {
+            $ext[] = 'mcrypt';
+        }
+
+        if (extension_loaded('gmp')) {
+            $ext[] = 'gmp';
+        } elseif (extension_loaded('bcmath')) {
+            $ext[] = 'bcmath';
+        }
+
+        if (!empty($ext)) {
+            $identifier .= ' (' . implode(', ', $ext) . ')';
+        }
+
+        return $identifier;
+    }
+
     /**
      * Key Exchange
      *
diff --git a/tests/Net/SSH2Test.php b/tests/Net/SSH2Test.php
index 954fb8b2..3177a323 100644
--- a/tests/Net/SSH2Test.php
+++ b/tests/Net/SSH2Test.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @author     Marc Scholten <marc@pedigital.de>
  * @copyright  MMXIII Marc Scholten
@@ -7,6 +8,17 @@
 
 class Net_SSH2Test extends PhpseclibTestCase
 {
+    /**
+     * @return Net_SSH2
+     */
+    private function createSSHMock()
+    {
+        return $this->getMockBuilder('Net_SSH2')
+            ->disableOriginalConstructor()
+            ->setMethods(array('__destruct'))
+            ->getMock();
+    }
+    
     public function formatLogDataProvider()
     {
         return array(
@@ -29,13 +41,44 @@ class Net_SSH2Test extends PhpseclibTestCase
      */
     public function testFormatLog(array $message_log, array $message_number_log, $expected)
     {
-        $ssh = $this->getMockBuilder('Net_SSH2')
-            ->disableOriginalConstructor()
-            ->setMethods(array('__destruct'))
-            ->getMock();
+        $ssh = $this->createSSHMock();
 
         $result = $ssh->_format_log($message_log, $message_number_log);
-
         $this->assertEquals($expected, $result);
     }
+    
+    public function generateIdentifierProvider()
+    {
+        return array(
+            array('SSH-2.0-phpseclib_0.3', array()),
+            array('SSH-2.0-phpseclib_0.3 (gmp)', array('gmp')),
+            array('SSH-2.0-phpseclib_0.3 (bcmath)', array('bcmath')),
+            array('SSH-2.0-phpseclib_0.3 (mcrypt)', array('mcrypt')),
+            array('SSH-2.0-phpseclib_0.3 (mcrypt, gmp)', array('mcrypt', 'gmp')),
+            array('SSH-2.0-phpseclib_0.3 (mcrypt, bcmath)', array('mcrypt', 'bcmath')),
+        );
+    }
+
+    /**
+     * @dataProvider generateIdentifierProvider
+     */
+    public function testGenerateIdentifier($expected, array $requiredExtensions)
+    {
+        $notAllowed = array('gmp', 'bcmath', 'mcrypt', 'gmp');
+        foreach($notAllowed as $notAllowedExtension) {
+            if(in_array($notAllowedExtension, $requiredExtensions)) {
+                continue;
+            }
+
+            if(extension_loaded($notAllowedExtension)) {
+                $this->markTestSkipped('Extension ' . $notAllowedExtension . ' is not allowed for this data-set');
+            }
+        }
+
+        $ssh = $this->createSSHMock();
+        $identifier = $ssh->_generate_identifier();
+
+        $this->assertEquals($expected, $identifier);
+    }
+
 }