Explore the Cardano consensus layer in this comprehensive conference talk from RWC 2021. Delve into distributed computation over networks, implementation challenges, and the correctness toolbox. Learn about transaction ledgers, consensus mechanisms, and networking protocols. Discover techniques for testing concurrent code in simulation and understand the importance of session types in network protocols. Examine the block-fetch process, forecasting, and denial of service prevention. Investigate the hard-fork combinator and strategies for de-risking decentralization. Gain insights into careful refinement processes and potential future developments in cryptocurrency consensus systems.