Complex sentence: Android Privacy Guard (APG) is a free and open-source app for the Android operating system that provides strong, user-based encryption which is compatible with the Pretty Good Privacy (PGP) and GNU Privacy Guard (GPG) programs.
Split into simpler sentences: Android Privacy Guard (APG) is a free and open source software application that runs on the Android operating system. The application provides strong, user-based encryption which is compatible with the Pretty Good Privacy (PGP) and GNU Privacy Guard (GPG) programs.