Crypt

Are you afraid of Facebook and the NSA snooping your messages over an unsecure channel such as Facebook chat, sms, or Hangouts? Manually encrypt your messages with Crypt, and even if the NSA intercepts your message via their convenient backdoor into Facebook, they will not be able to read its contents.

Easily encrypt text with 256-bit AES. Share the password used for encrypting with your friends through a secure channel, and use the password to decrypt the messages again.