Ethereum co-founder has surprised the community once again. Instead of directly promoting ETH, Vitalik Buterin built a prototype of an anonymous billboard based on zero-knowledge proof (ZK-proof) technology. The project, created in the style of so-called "vibe coding" where AI tools wrote most of the code for him, is deployed on the Aztec platform — a privacy-focused blockchain built on Ethereum's cryptographic foundation.
Return to the idea of privacy
The concept of an anonymous bulletin board with moderation is not new for Buterin. He first described it back in 2022 in an essay dedicated to zero-knowledge proofs and privacy. The essence is simple: each user can post anonymously, and moderators have the right to remove violations without knowing the authors' identities. Cryptographic "nullifiers" based on the poseidon2 hash function confirm the user's right to post and block duplicates without revealing the author.
This prototype is not just a toy. It fits into Buterin's broader agenda, as he regularly returns to the topic of privacy protection. Earlier this month, he warned about the revival of the Chat Control initiative in the EU, which threatens everyday cybersecurity by requiring the scanning of personal communications for prohibited content.
Architecture and implementation
In the aztec_experiments repository on GitHub, there are three working prototypes: a token contract, an oracle for voting, and the billboard itself. Before sending data to the blockchain, a private function checks with the associated token contract: whether the user has the right to post. 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. In Buterin's case, it means he described the task in simple terms, and the AI generated most of the code. This once again highlights his style — getting involved in curious side projects far removed from Ethereum's main roadmap.
Buterin's usual style
A humorous post has already appeared on the billboard's demo version: the author asked why Buterin is engaged in curious endeavors instead of developing his own coin. There is a pattern to this joke. In 2025, Vitalik has spent almost all his time on third-party projects far from Ethereum's development course. Among them — the task of recognizing anonymous authorship, which was ultimately 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 ETH's bullish prospects than the co-founder's side projects. Vitalik does not seem bothered by this: he finds cryptographic experiments more interesting than publicly supporting Ethereum.
Cryptalist expert opinion: While the market expects Buterin to engage in marketing activities to boost ETH's price, he continues to do what he considers important — building the foundation for a truly decentralized web. This prototype is not just a hobby, but a demonstration of how ZK technologies can solve real problems of privacy and moderation. Investors might need to get used to it: Buterin is not a CEO, but an architect, and his priorities lie in technology, not tokenomics.