Text- in a similar way TextSecure did it, would be my guess. They have something called Silent Text, and they're using the ideas here I believe: http://eprint.

Text- in a similar way TextSecure did it, would be my guess. They have something called Silent Text, and they're using the ideas here I believe: http://eprint.iacr.org/2014/036.pdf http://eprint.iacr.org/2014/036.pdf Email? They've announced the DarkMail protocol last year, and should be coming soon: http://darkmail.info/ http://darkmail.info/ https://www.youtube.com/watch?v=IgV_Z6V_llk https://www.youtube.com/watch?v=IgV_Z6V_llk