 <?php
 class PG_Controller_Plugin_RPK
extends Zend_Controller_Plugin_Abstract
  {
    
    protected $_key;
    
    /**
      * Set the encryption key
      * @param array $args OPTIONAL array['key'] = encryption key
    */
    public function __construct($args )
    {
      $this->_key = 'nedbank'; //default value
      
    }
    
    public function encrypt($input)
    {
      $this->_key = substr(md5($this->_key), 0, 24);
      $td = mcrypt_module_open('tripledes', '', 'ecb', '');
      $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
      mcrypt_generic_init($td, $this->_key, $iv);
      $encrypted_data = mcrypt_generic($td, $input);
      mcrypt_generic_deinit($td);
      mcrypt_module_close($td);
      return trim(chop($this->_url_base64_encode($encrypted_data)));
    }
    
    public function decrypt($input)
    {
      $input = trim(chop($this->_url_base64_decode($input)));
      $td = mcrypt_module_open('tripledes', '', 'ecb', '');
      $this->_key = substr(md5($this->_key), 0, 24);
      $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
      mcrypt_generic_init($td, $this->_key, $iv);
      $decrypted_data = mdecrypt_generic($td, $input);
      mcrypt_generic_deinit($td);
      mcrypt_module_close($td);
      return trim(chop($decrypted_data));
    }
    
    protected function _url_base64_encode($str)
    {
      return strtr(base64_encode($str),
        array(
          '+' => '.',
          '=' => '-',
          '/' => '~'
        )
      );
    }
    
    protected function _url_base64_decode($str)
    {
      return base64_decode(strtr($str,
        array(
          '.' => '+',
          '-' => '=',
          '~' => '/'
        )
      ));
    }
    
  }