title: PHP Fatal error: Class 'Crypt_RSA' not found
body: <p>I'm using php <a href="http://phpseclib.sourceforge.net/" rel="nofollow">phpseclib</a>.And i get following error when execute the script</p>
  
  <pre><code> PHP Fatal error:  Class 'Crypt_RSA' not found
   in /home/xxxxx/public_html/index.php on line 5
  </code></pre>
  
  <p><strong>PHP SCRIPT</strong></p>
  
  <pre><code>&lt;?php
  
  include('library/php/Net/SSH2.php');
  
  $key = new Crypt_RSA();
  $key-&gt;setPassword('891600909v');
  $key-&gt;loadKey(file_get_contents('891600909'));&lt;--This is the pvt key file in home directory in my ubuntu PC--&gt;
  
  $ssh = new Net_SSH2('www.xxxxx.com');
  if (!$ssh-&gt;login('xxxxx.com', $key)) {
      exit('Login Failed');
  }
  
  echo $ssh-&gt;read('xxxxx.com@xxxxx.com:~$');
  $ssh-&gt;write("ls -la\n");
  echo $ssh-&gt;read('xxxxx.com@xxxxx.com:~$');
  
  ?&gt;
  </code></pre>
  
  <p>How could i solve this issue ?</p>