Ethereum co-founder Vitalik Buterin has once again surprised the community by building a prototype of an anonymous billboard based on zero-knowledge proof technology. Instead of engaging in direct marketing for ETH, he chose to dive into a niche but critically important cryptographic experiment.
Buterin himself called this approach "vibe coding": he described the task in simple terms, and AI tools wrote a significant portion of the code for him. The project is deployed on Aztec, a blockchain focused on privacy and built on Ethereum's cryptographic foundation.
A Return to the Idea of Privacy
The concept of an anonymous billboard with moderation was first introduced by Buterin in 2022 in an essay about zero-knowledge proofs. At the time, he described a message board where anyone could post anonymously, and moderators could remove violations without knowing the authors' identities.
Buterin 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 personal communications for prohibited content. He believes privacy tools must be protected more strongly, as any relaxation would result in a loss of security. His large-scale 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 publish and simultaneously block duplicate posts without revealing the author.
Before sending data to the blockchain, a private function checks with the associated token contract to see if 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 interested in curious projects instead of developing his own coin. There is a pattern in such jokes. In 2025, Vitalik spent almost all his time on third-party projects far removed from Ethereum's development path. These include 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 even 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.
Expert opinion: While the market expects Buterin to aggressively market ETH, he is methodically building privacy infrastructure. This is a long-term strategy that could pay off when regulators begin to pressure confidentiality. But in the short term, such behavior is unlikely to support Ethereum's price.