Vitalik Buterin has built an anonymous billboard prototype on Aztec, a privacy-focused network that runs on Ethereum's underlying cryptography. The project uses zero-knowledge proofs to let anyone post without revealing their identity, while still allowing moderation to block rule violations. It's the latest in a string of side projects from the Ethereum co-founder that have little to do with ETH's price.
How the billboard works
Buterin called the project 'vibe coded' — he described the intended behavior in plain language and let AI tools write much of the code. The concept was first sketched in a 2022 essay on zero-knowledge proofs for privacy, imagining a message board where anyone could post anonymously with moderation that blocks rule violations without revealing identity.
The billboard uses cryptographic nullifiers built with a hashing method called poseidon2. These nullifiers confirm posting rights and block double-posting without revealing who posted. The demo post on the billboard joked about why Buterin is always doing fun things instead of pumping ETH. The code lives in a GitHub repository called 'aztec_experiments', which contains three working prototypes: a token contract, a voting oracle, and the billboard.
A pattern of side projects
Buterin has spent much of 2026 on side projects unrelated to Ethereum's price. He's mentioned writing a fantasy novel under a verified pseudonym, with authorship provable without exposing his real identity. He also ran an anonymous authorship challenge. His GitHub history suggests these projects aren't slowing down.
Earlier this month, Buterin warned that the EU Chat Control revival threatens everyday cybersecurity by reviving mandatory scanning of private messages for illegal content. The timing isn't great for Ethereum's market narrative. Ether has traded well below its prior cycle highs in 2026, and Wall Street's bull case for ETH has drawn more attention than Buterin's tinkering.
The billboard is a prototype, not a product. But it shows the kind of privacy tech Buterin is still pushing. Whether it gets built out into something bigger — or stays a demo on GitHub — remains to be seen. For now, the code is public, and anyone can poke around the three prototypes in the 'aztec_experiments' repo.
