Ethereum co-founder Vitalik Buterin built a small anonymous billboard demo using zero-knowledge proofs. He joked that he keeps picking fun side projects over promoting ETH.

Buterin called the project vibe coded. He described the intended behavior in plain language and let AI tools write much of the code. Vitalik built it on Aztec, a privacy-focused network that runs on Ethereum’s underlying cryptography.

An Old Privacy Idea Returns

Buterin sketched the anonymous billboard with the moderation concept in a 2022 essay on zero-knowledge proofs for privacy. The idea imagined a message board where anyone could post anonymously. A moderation system could still block rule violations. It would never learn who posted what.

Buterin keeps returning to this privacy theme. Earlier this month, he warned that the EU Chat Control revival threatens everyday cybersecurity. The proposal would revive mandatory scanning of private messages for illegal content. He argued that private tools need stronger protection, not weaker rules. His broader Lean Ethereum roadmap leans on similar cryptographic building blocks.

How the Billboard Works

The GitHub repository, named aztec_experiments, holds three working prototypes. They include a token contract, a voting oracle, and the billboard itself. The billboard relies on cryptographic nullifiers built with a hashing method called poseidon2. These nullifiers confirm a poster’s right to post. They also block double-posting, all without revealing an identity.

A private post function checks eligibility against a linked token contract. The check happens before anything reaches the chain. This approach echoes vibe coding. Andrej Karpathy popularized the term before he recently joined Anthropic. Buterin explained the build himself in

A Familiar Pattern for Buterin

The billboard’s own demo post carried a joke. It asked why Buterin is always doing fun things instead of pumping his own coin. The joke fits a pattern. Vitalik spent much of 2026 on side projects unrelated to Ethereum’s price. These included an anonymous authorship challenge that outside researchers eventually solved, plus early chapters of a decentralized governance novel.

The timing sharpened the joke. Ether has traded well below its prior cycle highs this year, and Wall Street’s bull case for ETH has drawn far more attention than any single side project. Buterin appeared unbothered by the contrast, choosing cryptography experiments over pushing Ethereum.

Vitalik Buterin has even mentioned writing a fantasy novel under a verified pseudonym. He would do this if his authorship could someday be proven the same way, without exposing his real identity. Whether the billboard demo grows beyond a prototype remains unclear. Still, Buterin’s GitHub history suggests these side projects are not slowing down.

Source: BeInCrypto