This really is false <i>marketing</i>, but technically what they're doing seems reasonable. Key quote:<p>> <i>Matthew Green, a cryptographer and computer science professor at Johns Hopkins University, points out that group video conferencing is difficult to encrypt end to end. That’s because the service provider needs to detect who is talking to act like a switchboard, which allows it to only send a high-resolution videostream from the person who is talking at the moment, or who a user selects to the rest of the group, and to send low-resolution videostreams of other participants. This type of optimization is much easier if the service provider can see everything because it’s unencrypted... This isn’t impossible, though, Green said, as demonstrated by Apple’s FaceTime, which allows group video conferencing that’s end-to-end encrypted. “It’s doable. It’s just not easy.”</i><p>Group videoconferencing is inherently centralized through a server that needs to analyze video/audio not only for signals as to who's talking, but also mix normalized audio and re-encode streams not just for lower thumbnail resolutions, but for clients with different bitrates.<p>I don't doubt that FaceTime finds a way to do this, but everyone is using Zoom instead because its performance is way better. I'm not entirely sure that <i>all</i> the necessary signal processing can be done performantly client-side, especially when you're allowing for a wide variety of endpoints (WebRTC, phone calls, etc.). You certainly can't mix encrypted audio (at least to the best of my knowledge?), for instance, which means increased bandwidth to everyone to handle overlapping speakers (someone interjecting "could I just say something?" while two other people are talking).<p>Also, handling key management for <i>groups</i> of people where you don't have the bandwidth to re-encrypt the stream separately for each receiver is very complex too, and in the end you're basically just going to have to trust that Zoom itself can't access the keys. Because usually Zoom <i>will</i> be able to, so that it can handle phone dial-ins.<p>But regardless... while Zoom should absolutely advertise full encryption, Zoom should absolutely <i>not</i> advertise <i>end-to-end</i> encryption. That's bad, and harms user trust in security overall when advertised technical terms become meaningless.