Briar, the peer-to-peer, end-to-end encrypted messaging app that sends and receives messages using the Tor network, entered public beta last July. The app is now out of beta and has released version 1.0. Briar says it's a service for "activists, journalists, and anyone else who needs a safe, easy and robust way to communicate." You can grab it now on the Play Store.

Briar
Briar
Developer: Briar Project
Price: Free