http://u.qdnx.org/file/fsf-20200405T231005-gkk5csl.html
Also happening now: software developer Charles Lehner provides an intro to Secure Scuttlebutt, a technology for decentralized, peer-to-peer, offline-first social media applications based on cryptographic identities. Watch #LibrePlanet2020 at https://u.fsf.org/live.