HOODED documentation

HOODED is a zero-knowledge shielded pool for private transfers on Robinhood Chain. Experimental

What is HOODED

HOODED lets you deposit into a shared on-chain pool and later withdraw to any address, breaking the public link between the deposit and the withdrawal. It is a faithful port of the Privacy Cash protocol (Tornado-Nova UTXO lineage).

How it works

Notes (UTXOs). A deposit creates a secret note — an amount owned by a key derived from your wallet signature. Notes live as commitments in the pool.
Merkle tree. Every commitment is a leaf in an incremental Merkle tree. Your browser rebuilds the tree from on-chain events to prove a note exists.
Zero-knowledge proofs. To withdraw, your browser builds a Groth16 proof that you own an unspent note and that value is conserved — without revealing which note.
Nullifiers. Spending a note publishes a nullifier so it can't be spent twice, without linking back to the deposit.
Relayer. An optional relayer submits your withdrawal so the recipient needs no gas and your address stays hidden (a small fee applies).

Privacy model

Read this before using HOODED. We state the limits plainly.

HOODED hides which deposit funds a withdrawal. That is the core privacy guarantee.
It does NOT hide amounts, timing, or asset. Deposits and withdrawals are public transactions; only the link between them is broken.
Self-relay reveals your address. If you submit your own withdrawal (self-relay), the transaction comes from your wallet and exposes your address. Use the relayer to avoid this.
The relayer sees your IP and timing. Using the relayer hides your address on-chain, but the relayer service receives your network request and can observe your IP, the timing, the amount and the recipient it submits for you. Self-relay avoids trusting any relayer — at the cost of revealing your address on-chain. Neither mode is fully private; see Privacy tips.
This is shielded privacy, not anonymity. Correlating amounts and timing can still de-anonymize careless usage — see Privacy tips.
Not yet audited. An independent audit is on the roadmap. Until then, treat HOODED as experimental and use amounts you can afford to lose.

User guide

1. Connect

Connect a supported wallet (see Wallet compatibility). HOODED requires Robinhood Chain (chainId 4663); if your wallet is on another network the app blocks signing and offers a one-tap switch. HOODED never signs or sends on the wrong network.

2. Deposit

Enter an amount and deposit. Your browser builds a proof and creates a private note. The note (with its secret blinding factor) is stored in your browser.

Keep your notes. Notes are held in your browser's local storage. If you clear site data or switch devices before withdrawing, those notes can be unrecoverable. Withdraw before clearing storage, and always keep access to the wallet you deposited with.

3. Send (withdraw)

Enter a recipient (any address) and an amount, then choose a mode:

Mode	Who submits & pays gas	Fee	Address exposure
Relay	The relayer (recipient needs no gas)	0.3% of the amount, netted from your note	Your address stays hidden
Self-relay	You (you pay gas)	None	Reveals your address

Fees & the Max button

Relayed sends cost 0.3% (30 bps), shown inline as you type. A single note must cover amount + fee (note consolidation is a future feature), so the Max button fills the largest value your biggest note can send: for relay that is the note minus the fee; for self-relay it is the whole note. Amounts above that are blocked with a clear message before you submit.

Privacy tips

Withdraw to a fresh wallet you don't reuse or link to your identity.
Avoid unique amounts. Withdrawing an oddly specific amount that matches a deposit is easy to correlate. Prefer round amounts.
Add time between deposit and withdrawal. Immediate withdrawals are the easiest to link.
Prefer relay — the recipient needs no gas and your address is never exposed.
Space out activity. Batching several deposits/withdrawals at once, or reusing the same amounts, leaks patterns.
Don't withdraw the full deposit immediately to one address — it recreates the link you were trying to break.

Wallet compatibility

HOODED derives your private shielded key from a wallet signature, and the wallet must be on Robinhood Chain.

Wallet	Message signing (key derivation)	Status
MetaMask	✓ `personal_sign`	Supported
OKX Wallet	✓ `personal_sign`	Supported — verified on mainnet
Trust Wallet	✗ raw message signing on this chain; typed-data fallback attempted	Not yet usable — use MetaMask or OKX

One wallet, one method. Your shielded key comes from your signature, and different signing methods (personal_sign vs EIP-712 typed data) produce different keys. Use a single wallet consistently. Don't move a shielded balance between wallets that sign differently — the notes derived under the other method won't be visible (funds aren't lost; reconnect the original wallet to see them).

Security & ceremony

Groth16 proofs are only as sound as the proving key they were built with. HOODED replaced its insecure development key with a production key from a multi-party Phase-2 trusted-setup ceremony (deterministic init → two independent contributors → a public, pre-committed drand beacon). The dev key was retired everywhere.

The full transcript, artifacts and re-verification commands are public: gitlab.com/Brouie/hoodedcash (release ceremony-v1). Anyone can reproduce the chain:

sha256sum transaction2_prod.zkey     # ea2c3dcf…5905
npx snarkjs zkey verify transaction2.r1cs powersOfTau28_hez_final_17.ptau transaction2_prod.zkey
# expect: #1 Tokensuit, #2 vlad, #3 final public beacon, "ZKey Ok!"
curl https://api.drand.sh/52db9ba70e0cc0f6eaf7803dd07447a1f5477735fd3f661792ba94600c84e971/public/30529000
# expect randomness f6013b22…f11a

Deployed contracts (chainId 4663): HoodedPool 0x04D06eD0…56D29, TransactionVerifier 0xa384b4EE…77221 — both verified on the block explorer.

Audit status & roadmap

HOODED has not yet been independently audited. An independent security audit is planned on the roadmap. Until it is completed, the strongest assurance available is transparency: the trusted-setup ceremony above gives verifiable, reproducible provenance, and all contracts, circuits and artifacts are public for review.

Not yet audited. HOODED is experimental software provided without warranty; an independent audit is planned but has not been performed. Reads and proofs run in your browser and keys never leave your device — but use at your own risk.

FAQ

Is HOODED audited?

Not yet. HOODED has not been independently audited; an audit is part of the roadmap. Until then, treat it as experimental and use amounts you can afford to lose.

What are the fees?

0.3% (30 bps) on relayed sends, netted from your note. Self-relay has no protocol fee — you pay network gas instead.

Can I use Trust Wallet?

Not yet — Trust Wallet can't sign the messages HOODED needs on this chain. Use MetaMask or OKX.

Where are my funds / notes stored?

Your notes live in your browser's local storage, secured by a key derived from your wallet signature. Clearing site data or switching devices can make notes unrecoverable — so use Settings → Export notes to save an encrypted backup (only the same wallet can decrypt it) and Import notes to restore it. Automatic note recovery from the wallet alone is on the roadmap.

Does HOODED make me anonymous?

No. It hides the deposit↔withdrawal link. Amounts, timing and asset are public, and self-relay reveals your address. See the Privacy model.

Which network?

Robinhood Chain mainnet (chainId 4663). The app blocks signing/sending on any other network.

Terms of Use

Draft — subject to legal review. The following is a template and not legal advice. It must be reviewed by qualified counsel before being relied upon.

By accessing or using the HOODED web interface (the "Interface") you agree to these Terms.

1. Eligibility

You must be of legal age and legally permitted to use the Interface in your jurisdiction. You may not use the Interface if you are located in, or a resident of, any jurisdiction where doing so would be unlawful, or if you are subject to applicable sanctions.

2. Non-custodial, self-service software

The Interface is a non-custodial tool that helps you interact with public smart contracts. It never takes custody of your assets or keys. You are solely responsible for your wallet, keys, note data, and every transaction you authorize.

3. Prohibited use

You agree not to use the Interface for any unlawful purpose, including money laundering, terrorist financing, evading sanctions, or handling proceeds of crime, or in violation of any applicable law or regulation.

4. Unaudited software; no warranty

The Interface and the underlying protocol are experimental and unaudited, and are provided "AS IS" and "AS AVAILABLE" without warranties of any kind, express or implied, including merchantability, fitness for a particular purpose, and non-infringement. No guarantee is made as to availability, security, or correctness.

5. Assumption of risk

You understand and accept the risks of blockchain systems and experimental cryptography, including smart-contract vulnerabilities, key/note loss, transaction irreversibility, network failures, and total loss of funds. You use the Interface at your own risk.

6. Limitation of liability

To the maximum extent permitted by law, the contributors to HOODED shall not be liable for any indirect, incidental, special, consequential, or exemplary damages, or any loss of funds, profits, or data, arising from your use of or inability to use the Interface.

7. Changes

These Terms may be updated. Continued use after changes constitutes acceptance.