Top 5 Android apps for privacy and security | AndroidGuys. Okay, let's start where I always do. Privacy and Security in the modern world are no more. Anyone, anywhere, can be hacked, and you probably will, sooner or later. That said, however, you can get a long way towards making that possibility pretty remote; and, you can likely prevent hacks from anyone but a determined government or large organization. These 5 apps are highly recommended. I use Protonmail for encrypted, secure email, and Signal for secure messaging for client critical matters. As for VPN software, pick one; but, research it first. Use VPN all the time; not some of the time. Be careful out there.