ChatSecure is a free iOS app for end to end encrypted chat with the Off The Record messaging system able to communicate with any chat software based on XMPP, like Google Talk, Jabber, Facebook, Oscar IM and ChatSecure in Android, it will not work with Yahoo Messenger or Skype contacts.
The app settings are simple but effective, you can change chat font size, set to autodelete chats on disconnect and get a warning before automatic sign out, your friends (Buddy list) chat accounts are accessible with a single tab on the side bar, each account has a logo indicating the messaging system your they are using, when you first establish a connection you will be shown the encryption key fingerprint and ask to verify it, this stops man in the middle attacks where someone injects a fake encryption key in between you and the other end to be able to listen in.
ChatSecure encrypted iPad chat
With this app there is no central server to store or monitor your data and third party eavesdropping is not possible because ChatSecure encrypts communications but you would still need to make sure that your acquaintance mobile device has not been stolen and he is who he claims to be, you also need to be aware that you are not anonymous in ChatSecure, the app will encrypt messaging but not hide the IP behind them, for anonymity add a VPN provider before starting the chat.
ChatSecure offers perfect forward secrecy, this means that temporary private encryption keys are generated for each session so if you lose them the keys can not be used to decrypt past chat logs or linked to you.
