public function encrypt($data)
{
$module = $this->openCryptModule();
$key = $this->substr(md5($this->getEncryptionKey()), 0, mcrypt_enc_get_key_size($module));
srand();
$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($module), MCRYPT_RAND);
mcrypt_generic_init($module, $key, $iv);
$encrypted = $iv . mcrypt_generic($module, $data);
mcrypt_generic_deinit($module);
mcrypt_module_close($module);
return $encrypted;
}