PHP Snippet for Magento - Encrypt / Decrypt cookie

Data.php

<?php

/**
 * Mum ! I want complex cookie
 */

class Bonne_Maman_Helper_Data extends Mage_Core_Helper_Abstract
{
    private static $secret = 'What is the answer to Life, the Universe, and Everything'; // Can be also a in conf

    /**
     * Encrypt the content of the cookie
     *
     * @param string $cookieName
     * @param array $data
     * @param string $lifetime
     */
    public function createEncryptedCookie($cookieName = '', $data = array(), $lifetime = '')
    {
        try {
            if (empty($cookieName) || is_null($cookieName)) {
                Mage::throwException($this->__('Call to ' . __CLASS__ . ' without cookie name.'));
            }
            if (empty($data) || !is_array($data)) {
                Mage::throwException($this->__('Call to ' . __CLASS__ . ' without $data or not array type.'));
            }
            if (empty($lifetime)) {
                $lifetime = strtotime("+1 year");
            }

            $key = self::$secret;
            $string = json_encode($data, JSON_FORCE_OBJECT);

            // Encrypt
            $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
            $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
            $encryptedData = base64_encode($iv . mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $string, MCRYPT_MODE_CBC, $iv));

            /** @var Mage_Core_Model_Cookie */
            Mage::getModel('core/cookie')->set($cookieName, $encryptedData, $lifetime, '/');
        } catch (Exception $e) {
            Mage::getSingleton('core/session')->addWarning($e->getMessage());
            Mage::logException($e);
            return;
        }
    }


    /**
     * Return the content of encrypted cookie
     *
     * @param   string      $cookieName The cookie name
     * @return  stdClass    $data       Content of the cookie
     */
    public function readEncryptedCookie($cookieName = '')
    {
        try {
            if (empty($cookieName) || is_null($cookieName)) {
                Mage::throwException($this->__('Call to ' . __METHOD__ . ' without cookie name.'));
            }

            $key = self::$secret;
            /** @var Mage_Core_Model_Cookie $string */
            $string = Mage::getModel('core/cookie')->get($cookieName);

            // Decrypt
            $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);

            $encrypted_dec = base64_decode($string);
            $iv_dec = substr($encrypted_dec, 0, $iv_size);
            $encrypted_dec = substr($encrypted_dec, $iv_size);

            $decryptedData = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $encrypted_dec, MCRYPT_MODE_CBC, $iv_dec);
            $data = json_decode(trim($decryptedData));

            return $data;
        } catch (Exception $e) {
            if(isset($_SERVER['MAGE_IS_DEVELOPER_MODE'])){
              Mage::getSingleton('core/session')->addWarning($e->getMessage());
              Mage::logException($e);
              return;
            }
        }
    }
}