zRTP end-to-end encryption in Sylk Suite

AG Projects has rolled out zRTP end-to-end encryption across its Sylk Suite stack. The implementation is cross-platform and supported by the SIP SIMPLE client SDK, the Blink SIP client, and the Sylk Mobile and Web clients.

On WebRTC clients (mobile and browser) the implementation relies on the Insertable Streams technique. Insertable Streams expose encoded media frames to JavaScript before they hit the network, allowing zRTP-derived keys to be applied end-to-end on top of the hop-by-hop SRTP that the WebRTC stack already provides — so audio and video stay encrypted all the way between peers, even when traffic traverses SylkServer or a TURN relay.

Implementation details, key-exchange flow and verification UX are documented in the Sylk Mobile repository: github.com/AGProjects/sylk-mobile/tree/master/docs/encryption.