RedPhone is the equivalent of Signal recommended by Snowden for Android mobile devices. It performs much of the same tasks, offering completely encrypted voice calls to users, for free. You can call your friends and family without worrying about your calls being monitored or intercepted by third parties. RedPhone and Signal both use your phone number as the account identifier, which means that you don’t have to create additional accounts. These two apps are also open source, which means anyone can verify the code of the app can be verified by anyone competent enough to do so. By using RedPhone or Signal and urging your friends and family to use it, too will promote the ideals Snowden is so confident about. It might be hard at first, to get everybody on board with yet another app on their phones, but the benefits are definitely worth it. You can get the app for free from the Google Play Store.