The MP02 is the first voicephone to offer a downloadable privacy feature that uses the Signal protocol to provide free, encrypted Internet-based calls and texts worldwide via Wi Fi or mobile data (subject to data charges). We believe Signal provides vastly greater security compared to the widely-used encrypted alternatives, which exist primarily as tools for harvesting and selling valuable metadata (contacts lists, who communicated with whom, when it happened, etc.). In the Signal system, all metadata is encrypted.
By using the Signal-protocol, it is possible to add group messaging and voice messages to the MP02.