Vitalik Buterin Releases Aztec-Based Anonymous Bulletin Board Demo

Ethereum co-founder Vitalik Buterin has developed and released a demo for an anonymous bulletin board built on Aztec, a privacy-focused Layer 2 network.

The Block reported on July 20 that Buterin unveiled the project the same day on decentralized social network Farcaster. The demo is a test implementation of the “anonymous bulletin board with on-chain moderation” concept he proposed in a 2022 blog post. The source code has been posted on GitHub under the account vbuterin.

The bulletin board combines Ethereum Layer 1 with Aztec Layer 2. Users can deposit Ether on Ethereum Layer 1, post messages anonymously on Layer 2, and later withdraw the assets back to Layer 1. Public call data does not retain the sender’s address or details of the initial deposit, preserving anonymity.

The system includes an on-chain moderation layer. A moderation role designated at deployment can mark certain posts as inappropriate. Those posts are hidden from the default feed, and the author receives a time-limit penalty on the next post. A local large language model daemon monitors the board in real time and automatically detects policy-violating posts based on rules stored on-chain.

Posting frequency depends on deposit size. A deposit of 0.001 Ether allows one post per hour, while 0.01 Ether allows 10 posts per hour. The document says key security properties, including rate limiting, privacy and deposit safety, were formally verified across 70 theorems using Lean 4, a mathematical proof language. It says there are no unproven items.

Buterin wrote in a Farcaster post that “this demo can already do very interesting and non-trivial things.” The repository also states that some items remain unfinished, including access-control fixes and unverified browser flows.