Why encrypted group messaging isn't as secure as point to point. Dr Mike Pound explains this ongoing problem. Instant Messaging & the Signal Protocol: https://www.youtube.com/watch?v=DXv1boalsDI Double Ratchet Messaging Encryption: https://www.youtube.com/watch?v=9sO2qdTci-s Relevant paper: https://eprint.iacr.org/2017/666.pdf https://www.facebook.com/computerphile https://twitter.com/computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran's Numberphile. More at http://www.bradyharan.com/