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ROBIN POOL is one shielded pool per token on Robinhood Chain. Coins that enter stop being wallet balances and become notes: sealed commitments that only their owner can read or spend. Inside the pool nobody can see balances, senders, receivers or amounts. Coins can leave to any wallet, including a brand-new empty one, with a relayer paying the gas.

Native ETH and any ERC-20 on the chain can have a pool. If a token has none yet, one transaction opens it for everyone.

1. 1Connect. Any EVM wallet that announces itself in the browser (EIP-6963): MetaMask, Rabby, Coinbase Wallet, OKX and others. The app asks the wallet to switch to Robinhood Chain (chain id 4663).
2. 2Unlock. Sign one plain-text message. Your pool keys are derived from that signature inside the browser. Nothing is uploaded or stored; sign again next time and the same keys come back.
3. 3Shield. Pick a token, enter an amount, confirm once in the wallet. The coins move into the pool and you receive a note.
4. 4Pay or unshield. Pay a shielded address from Send, or take coins out to any wallet from Unshield. Both are submitted by the relayer, so you pay no gas and your wallet does not appear.

Deposits are ordinary transactions signed by your wallet: an ERC-20 approval the first time you shield a token, then the deposit itself. Private payments and unshields are built in your browser and handed to the relayer, which signs and pays for them, so your wallet is not involved at all. If the wallet does not know Robinhood Chain yet, the app offers to add it with RPC https://rpc.mainnet.chain.robinhood.com.

You sign a fixed message. From that signature the app derives two keys: a spending key, whose hash is your note public key, and an encryption key used to receive notes. Your shielded address starts with rp and carries both public keys. It is the same every session, it is safe to share, and the chain never mentions it. One wallet gives one shielded address; use separate wallets for separate identities.

A note is an amount, an owner key, a random blinding value and the token. On chain only its commitment is stored, a hash of those four values appended to the pool's Merkle tree, next to a short ciphertext that only the owner can decrypt. Two payments to the same person produce two unrelated commitments. Your balance is the sum of unspent notes your keys can open; the app finds them by trying to decrypt every ciphertext in the pool.

Every spend carries a zero-knowledge proof of three facts: the notes exist in the tree, you know their secrets, and value in equals value out. The proof reveals none of the inputs. Each spent note also publishes a nullifier, which the contract records so the note can never be spent twice. A nullifier cannot be traced back to its note. One proof spends up to two notes and creates two: a payment is one note for the recipient plus change for you.

The pool has two public doors: shield and unshield. Both show a wallet, a token and an amount, like any transaction on Robinhood Chain. Everything between the doors, holding and paying, shows nothing. A wallet that shields 1,000 and pays three people appears on chain as one deposit and three relayer transactions with no sender, receiver or amount.

The amount you enter is what leaves your wallet. The card shows what you will hold after the protocol fee before you confirm. Deposits count after one confirmation and show up in your shielded balance without a reload.

Paste the recipient's rp… address, enter an amount, send. Your browser builds the proof and the relayer submits it. The chain sees two new commitments, two nullifiers and a flat fee. The fee is flat on purpose: a percentage would be visible and would give the amount away.

Enter any Robinhood Chain address. The relayer signs and pays gas, so the destination can be a wallet that has never held ETH. The destination and amount are public; which deposit funded them is not. MAX fills in everything you can move after the fee.

Search a token or paste its contract. If no pool exists, opening one is a single transaction that anyone can send, and the pool then stays open for everyone. Tokens that take a fee on transfer are credited with what actually arrives. Gasless actions need a market price for the token so the relayer can quote its flat fee; shielding never does.

The protocol fee is set once at deployment (default 0.5%) and can never exceed 1%. The relayer fee covers its gas and is quoted live.

Your keys never leave the browser and are rebuilt from one signature each session. The relayer only ever sees finished proofs: it can refuse to submit, but it cannot spend, redirect or read your notes, because the recipient, amount and fee are bound into the proof. The contracts have no owner and no admin function; the protocol fee is fixed at deployment and capped at 1% in code. They have not been audited yet. The circuit's phase-2 trusted setup had one contributor on top of the public Perpetual Powers of Tau; a multi-party ceremony is planned before large amounts are accepted.