Very interesting, thanks. A question: how does it run on embedded systems? I was wondering of two very small boards, such as a Nano/Orange PI or similar ones implementing a VPN portable box that can be used both to connect PCs/tablets etc, and/or offering encrypted voip communications: plug one here, the other one there, give each other's ip addresses (using encrypted mail?) and you get a secured pipe to talk or send data through. (I assume the keys are hardcoded) Finding each other IP could be achieved by using an external trusted email server; each box cold employ a button to send a mail with a id:ip pair (or a daemon to do that every time it changes), so that the other box(es) know what is connected from where and keep the connection alive. Doable?