zipcoin ($ZC)

"Only Gladias and the restaurant knew that a 10.5 zipcoin order had been made." — Snowmoon, ch. 6

The currency from Vitalik Buterin's novel Snowmoon, shipped on Ethereum mainnet. Not affiliated with the author.

• Zip / unzip — deposit $ZC into a Privacy Pool, withdraw any amount to any address with a zero-knowledge proof built in your browser. (0xbow privacy-pools-core, the design from the 2023 Privacy Pools paper.)
• Burn to speak — burn zipcoins to post a message; the bigger the burn, the louder. Publicly from a wallet, or anonymously from a zipped note through a relayer that cannot alter the message.
• The Doorstep — burn at someone's door (ENS name or address) and optionally leave an anonymous gift. Every door has a page (/door/vitalik.eth) that collects everything burned there. Ch. 20.
• Farcaster Mini App — share any cast to zipcoin and knock at its author's door in one tap (/fc, /fc/share). Door links render as cards with a Knock button; people who added the app get buzzed when someone knocks at theirs (webhook + Postgres + notifier.ts). Manifest at /.well-known/farcaster.json.
• Veridian sales tax — 0.5% of every trade flows to the treasury on-chain, in real time.
• Private AI chat — chat.zipcoin.cash: fund a browser-only key from a zipped note, deposit into zkAPI's vault, talk to any model with short-lived keys straight from the browser. No account, no wallet connection; ask about a tx, a contract or a wallet without telling anyone it is yours; burn ZC to publish an answer to the Book; gift links. Open source: zipcoincash/zipcoin-chat. Works with zkAPI (Open Anonymity + EF dAI); experimental, no affiliation.

Site: https://zipcoin.cash · X: @zipcoincash · Token: 0x4E67DB19044549fF420860834c91b45BaD298722

Verify it yourself

• Proofs are generated client-side, in your browser, with the 0xbow SDK and its published circuit artifacts (https://zipcoin.cash/artifacts/…, SHA-256 digests match the SDK's). The on-chain verifiers are the ones securing 0xbow's own mainnet pool (0x022891F9…7D6d, 0xa45ACa86…5eC6). Nobody on the zipcoin side can forge a proof.
• The zip key is derived in the browser from a wallet signature (masterKeys, mnemonicFromSignature); it is never sent anywhere. The 12-word phrase is portable to any Privacy Pools tooling.
• The relayer can only submit what the proof already binds: recipient, fee and message live in withdrawal.data, which is hashed into the proof's context. See contracts/ZipcoinFork.t.sol::test_speakAnon_relayerCannotRewriteMessage. Every spending contract (ZipBroadcaster, ZipDoorstep, ZipTeller, ZipTellerEth, ZipHearth) is verified on Etherscan, has no owner, and holds nothing between calls.
• The pool never depends on the association set for custody: any depositor can ragequit back to their own wallet.
• The burn contract (contracts/ZipBroadcaster.sol) has no owner and holds nothing between calls. Burns go to 0x…dEaD.

Layout

• contracts/ — our Solidity (burn contract, mainnet-fork tests, deploy scripts) and deployment addresses. They live inside our fork of privacy-pools-core (branch zipcoin); see contracts/README.md.
• scripts/ — deploy the stack for a token, go-live, local anvil-fork rehearsal.
• The chat app lives in its own repo: zipcoin-chat. The agent SDK and MCP server: zipcoin-agent.

The website (zipcoin.cash) is a separate, closed-source Next.js app. Everything that matters for trust is on chain and in contracts/: the pool, the spending contracts, and the proofs your browser builds with 0xbow's open SDK.

Local mainnet-fork rehearsal of the contracts: anvil --fork-url <archive rpc> --chain-id 31337, then ./scripts/local-up.sh.

Trust and risks

The Privacy Pools contracts are audited upstream; ZipBroadcaster and the launchpad contracts are not. The Entrypoint is upgradeable by the zipcoin owner key, like the original. The relayer and association set are run by the team: they can delay approvals or refuse to relay, they cannot move coins. Anonymity grows with pool usage. $ZC is a volatile token; nothing here is investment advice.

MIT for our code. Vendored and forked components keep their own licenses (privacy-pools-core: Apache-2.0).