Firefox is well known for it's privacy concern and security. I think Firefox stored cookies but this information can only be stored if you provide it - websites cannot gain access to information you didn't provide to them, and they can't access other files on your computer. And you can easily turn off cookies on Firefox for Android by following this method: * Tap on menubar. Which is usually a hamburger like icon on the bottom of your device. * Then go to ''Settings > Privacy'' * Tap on the '''Cookies''' and select '''Disabled'''