Ethereum co-founder Vitalik Buterin is once again demonstrating his unique approach to ecosystem development. Instead of directly promoting ETH, he built a prototype of an anonymous billboard with moderation based on zero-knowledge proofs (ZK-proofs). Buterin jokingly noted that he is once again choosing curious side projects over marketing the native coin.
Notably, Buterin implemented this idea in the style of so-called vibe coding: he described the task in simple words, and AI tools wrote most of the code for him. The project is deployed on the Aztec blockchain — a privacy-focused platform built on Ethereum's cryptographic foundation.
Return to the Idea of Privacy
The concept of an anonymous bulletin board with moderation was first described by Buterin back in 2022 in an essay about zero-knowledge proofs. The idea is simple: any user can post anonymously, and moderators have the right to remove violations without knowing the authors' identities. This is not just an experiment — it is part of Buterin's broader philosophy, as he regularly returns to the topic of privacy protection.
Earlier this month, he warned that the revived Chat Control initiative in the EU threatens everyday cybersecurity by requiring checks on private correspondence for prohibited content. Buterin is convinced: privacy tools need to be protected more strongly, as weakening them would result in a loss of security. His extensive Lean Ethereum roadmap is built on similar cryptographic principles.
How the Billboard Works
In the aztec_experiments repository on GitHub, there are three working prototypes: a token contract, an oracle for voting, and the billboard itself. The billboard relies on cryptographic "nullifiers" based on the poseidon2 hash function. They confirm the user's right to post and simultaneously block duplicate posts without revealing the author.
Before sending data to the blockchain, a private function checks against the linked token contract: whether the user has the right to write. Buterin detailed the entire process in the first post of the thread. The term vibe coding was previously popularized by Andrej Karpathy, who recently joined Anthropic.
Buterin's Usual Style
A humorous post appeared on the demo version of the billboard: the author asked why Buterin is engaged in curious endeavors instead of developing his own coin. There is a pattern in such jokes. In 2026, Vitalik devoted almost all his time to third-party projects far from Ethereum's development path. Among them were a task for recognizing anonymous authorship, which was eventually solved by independent researchers, and the first chapters of a novel about decentralized governance.
Ethereum's price this year is noticeably lower than the peaks of the previous cycle, and Wall Street is much more eager to discuss the bullish prospects of ETH than the founder's side projects. Vitalik does not seem bothered by this: he finds cryptographic experiments more interesting than publicly supporting Ethereum.
Buterin has suggested that he might one day release a fantasy novel under a pseudonym: the same cryptography would prove that he wrote the book, but no one would know his name. Whether the billboard will remain a prototype is unclear. Judging by the history of changes on GitHub, Buterin continues to experiment just as actively.
My expert opinion: This project is not just a hobby. Buterin is once again demonstrating that fundamental research in ZK-proofs and privacy is a priority for him. For the long-term health of Ethereum, such experiments may prove more important than short-term marketing campaigns. The market may not notice this, but it is precisely these "side" projects that often become the foundation for the next major technological leap.