This lecture covers the importance of anonymity in decentralized systems, discussing the threats to online privacy from various entities like governments, ISPs, and advertisers. It explores the limitations of TLS/encryption in protecting metadata and introduces strategies like mix networks and Tor to achieve anonymity. The instructor delves into the workings of Tor, the challenges it faces, and the concept of Dining Cryptographers (DC-nets) for information-theoretic anonymity. The lecture concludes with recommended readings on Tor and anonymous communication systems.