function cookie_set($key, $value)
{
    setcookie(
        $key,
        base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($config['salt']), $value, MCRYPT_MODE_CBC, md5(md5($config['salt'])))),
        time()+$config['expire']
    );
}

function cookie_get($key)
{
    return rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($config['salt']), base64_decode($_COOKIE[$key]), MCRYPT_MODE_CBC, md5(md5($config['salt']))), "\0");
}

$config = array(
    // Database
    'db_host' => 'localhost',
    'db_user' => 'root',
    'db_pass' => '',
    'db_name' => '',

    // Cookies
    'salt' => 'xxx',
    'expire' => 1209600, // 14 days
);