ZeroKing

ZeroKing is a chess game where players must verify they have a .edu email before playing. It uses zero-knowledge proofs to check the email without revealing it.

The game runs on Mina using a custom zkApp built with o1js. Every move is verified inside a ZK circuit, so no one can cheat. Only valid moves are allowed, and no one needs to trust the other player.

At the end of a game — if someone resigns or the match is a draw — the result is shown and the player is redirected to the home page. Later, we’ll add NFTs that can be minted to prove a player’s win or participation.

ZeroKing brings together private identity, on-chain logic, and fair gameplay — with no trust required.

how it's made – zeroking

zeroking is a minimal chess game where players must prove they have a .edu email using zero-knowledge proofs. every move is validated inside a zero-knowledge circuit using o1js (mina protocol).

technologies used:

• sveltekit for the frontend and routing
• o1js (mina) to write zk circuits that validate chess moves
• zkemail + noir-jwt to generate zero-knowledge proofs of .edu email ownership
• tailwindcss for layout and spacing
• svelte-french-toast for toast messages
• svelte-ripple-action for button effects

the game logic:

• the entire chess ruleset (pawn movement, promotion, en passant, castling, etc.) is written using o1js
• game state is expressed in provable field and bool values
• all moves are validated using constraints and must pass zk proof checks
• no player can cheat or send invalid moves — even if they try to modify state manually

email gating:

• user inputs a .edu email
• a fake zk proof is generated using mocked logic (for now)
• in the future, this will be replaced with actual gmail-based zkemail verification using noir-jwt
• only users with valid .edu proofs can play

game end:

• if a player resigns or accepts a draw, a modal shows the result image
• after 3 seconds, the app redirects the user to the home page
• the modal uses a static image to simulate what an nft preview would look like

extras:

• transactions are wrapped in a function to manage state and timeouts
• everything is reactive but kept lightweight
• no backend is used
• nft minting will be added later using the zk proof data

partner tech:

• zkemail for identity proof
• mina (o1js) for zk chess logic
• ethglobal for infra and testing

this project is built around proof, not trust. no servers. no secrets. no ui distractions. just cryptographic rules and fair play.