Touch To Text is a secure messaging application for Android devices. Keys are exchanged using Diffie-Hellman over NFC, so you and your contacts are required to have a face to face meeting to exchange keys. This ensures the integrity and validity of public keys, and along with certificate pinning prevents any Man in the Middle attacks.
Messages are encrypted end to end, and delivered via Tor. Messages are authenticated and encrypted with public-key crypto.
Our server operates as a Tor Hidden Service, keeps no logs, and stores only the minimum information required to deliver messages.
We collect no data at all, except for the GCM IDs required to send encrypted messages. At no point do we ever collect any personally identifiable data.
For a more complete explaination, you can download our paper at http://cs.ucsb.edu/~iland/TouchToText.pdf