While people are starting to meet up again in person, group video calls are still pretty important to a lot of people especially this holiday season for those that still can’t. Having encrypted group video calls is a challenge though as there are limits to the number of people that can join in apps like WhatsApp and Signal. The latter though is now expanding their limit from 5 to 40, thanks to a new open-source calling service that they created for this purpose.
Previously, you could only get up to 5 people on an encrypted video call on Signal. This was because they used an open-source solution for its video calls which made it impossible for them to scale up and add more people in a call that would remain safe and private. So now they had to create their own open-source calling service that they have been testing and using for the past 9 months and so now they’re finally confident enough to allow up to 40 people to participate in the video call and keep it encrypted.
Signal now supports 40 person group calls. Building large end-to-end encrypted group calls required some new engineering. Learn how we did it here: https://t.co/i27rRqkI4l
— Signal (@signalapp) December 15, 2021
The service relied on something called Selective Forwarding which basically means that participants use servers that will forward their audio and video to the other people in the call without having to alter or view their content. The jump from 5 to 40 is pretty significant and will be useful for families and friend groups that are bigger than just five people. This holiday season would be a perfect time to test that out and see if the service will be able to handle both the calls and the encryption.
WhatsApp has been able to offer end-to-end encryption for video calls as well as messages. But for the video calls, they started with four and then were able to raise the limit to up to 8 people. So this 40 people limit for Signal is a significant advantage over the Meta-owned messaging app. Signal was one of the “beneficiaries” during the whole WhatsApp privacy policy kerfuffle as some disgruntled users switched to them and Telegram.
If you want to learn more about how Signal was able to come up with new engineering to support more people in encrypted video calls, you can check out their blog post. If you just want to try it out, go and start organizing that Christmas group video call with your loved ones.
