CA11 is a generic, open cross-platform communication tool(video, audio & data) for web(desktop) that aims to fill the gap between SIP/VoIP and proprietary communication services like Whatsapp & Signal. Its strategy is to first have a web implementation for Desktop, which can be rapidly developed using established API’s (WebRTC) and limited resources. Ultimately, the goal is to have both a web-version and a separate implementation for FOSS phones like the Librem 5 and the Pinephone.
CA11 has an abstraction for phone calls, which allows it to deal with multiple signalling protocols. Currently, it supports SIP and SIG11 signalling. The SIP implementation is being developed against a recent Asterisk build and volatile user accounts. SIG11(WiP) signalling relies on locally generated public key identities (WebCrypto). Matrix signalling is considered to be an extra candidate, since that is the signalling protocol of choice for the Librem phone app.
With SIG11, Calling in to a number is a bit like SSH’ing to an unknown domain. A user first needs to trust the public key through a handshake, before a call is made. The number is like a domain, but doesn’t have to be unique. This p2p calls with CA11 accessible, portable and privacy-friendly, since all signalling data is e2e encrypted. Just pick any number(or name) and be reachable instantly, or call any other number on the fly.
The CA11 project could use some help. Feel free to contact me if you have any questions. Some more info about the project: https://github.com/garage11/ca11