Ethereum co-founder Vitalik Buterin has shared a “vibe-coded” demo of an anonymous message board built on Aztec, Ethereum’s ZK privacy L2. Users deposit ETH on mainnet, post anonymously on L2 with no public link between a post and their wallet, and can withdraw later.

The twist is onchain moderation: a designated censor can flag posts as “immoral” — hiding them from default feeds and time-locking the poster’s next messages — while a local LLM daemon checks each post against a transparent onchain policy. Posts are rate-limited by deposit size (0.001 ETH = 1 post/hour), and the logic ships with 70 theorems formally proven in Lean 4. Based on his 2022 “anon billboard” blog idea, Buterin stressed the demo is early, incomplete and only a toy — with access-control fixes and browser flows still to do.