I have developed an instant messenger for Android called EnsiChat [1]. For identity, I use an RSA key pair. For key exchange, devices send their public key to

I have developed an instant messenger for Android called EnsiChat [1]. For identity, I use an RSA key pair. For key exchange, devices send their public key to direct neighbors, and you can visually check that the key is correct. I have also thought about implementing transport over internet (right now it's only Bluetooth). But that would require a lot of effort. [1] https://github.com/Nutomic/ensichat https://github.com/Nutomic/ensichat