In the third episode of Honest Majority, we speak with Aggelos Kiayias, Professor at the University of Edinburgh and Chief Scientist at IOG, about the foundations of blockchain consensus and how formal security assumptions shape real-world protocols. The conversation covers Aggelos’ path into cryptography, his early work on modeling Bitcoin’s consensus, and the motivation behind Proof-of-Stake systems that do not rely on hashing power. Using the recent Cardano incident as a case study, the discussion then covers disagreement among honest nodes, temporary adversarial majorities, and the self-healing properties of Ouroboros. The episode concludes with a forward-looking view on privacy-enhanced smart contracts, zero-knowledge techniques, and the need to design blockchain infrastructure that remains secure in a post-quantum setting.