Using Secure Chat
Micah Lee has a good tutorial on installing and using secure chat.
To recap: We have installed Orbot and connected to the Tor network on Android, and we have installed ChatSecure and created an anonymous secret identity Jabber account. We have added a contact to this account, started an encrypted session, and verified that their OTR fingerprint is correct. And now we can start chatting with them with an extraordinarily high degree of privacy.
FBI Director James Comey, UK Prime Minister David Cameron, and totalitarian governments around the world all don’t want you to be able to do this.