Understanding the Signal Protocol: Secure Messaging & Privacy 🔐

Video lectures for Alfred Menezes's introductory course on real-world deployments of cryptography. Topics covered: Signal, WhatsApp, forward secrecy, post-compromise security, root key establishment, keychains, message transmission. Lecture playlist: https://www.youtube.com/playlist?list=PLA1qgQLL41SRn_23p8zD0vUpKM4qOgt_T Course web page: https://cryptography101.ca/crypto101-deployments/ The slides are available on the course web page. Other cryptography courses: https://cryptography101.ca Slides 00:00 Introduction 01:28 Slide 100: Introduction 02:41 Slide 101: WhatsApp 03:30 Slide 102: Signal objectives (1) 05:29 Slide 103: Signal objectives (2) 08:20 Slide 104: Forward secrecy 10:18 Slide 105: Post-compromise security 11:43 Slide 106: Cryptographic ingredients 13:00 Slide 107: Signal protocol 14:20 Slide 108: Registration 16:12 Slide 109: Root key establishment 19:35 Slide 110: Verifying long-term public keys 20:51 Slide 111: Message transmission 21:42 Slide 112: Example of message transmission (1) 23:06 Slide 113: Alice's keychains 25:07 Slide 114: Example of message transmission (2) 25:17 Slide 115: Message transmission (2) 27:14 Slide 116: References