ShieldedPool (MASP)

The ShieldedPool, also called the MASP (Multi-Asset Shielded Pool), is Z’s home base. Assets deposited into the ShieldedPool become private notes. No outside observer can see who holds what, how much, or that a specific user is present at all. For more technical mechanics, see Privacy Architecture. This page covers the user-facing view: how to enter, what happens inside, and how to exit.

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How to Enter the ShieldedPool

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Stablecoins and Other ERC-20 Tokens (Available at Launch)

USDT and other ERC-20 tokens enter via LayerZero from Ethereum, Arbitrum, or Base. Shielded minting (private path):

1. Deposit USDT into the bridge contract on the source chain
2. Generate a Poseidon commitment off-chain (only the commitment crosses the bridge, no recipient address)
3. USDZ is minted into the ShieldedMinter vault (not to any user address)
4. Claim your note by proving ownership with a ZK proof

Your deposit on the source chain and your USDZ on Z are not linkable when you use shielded minting. An observer on the source chain sees that stablecoins were locked and a commitment was created. They cannot link the commitment to any address on Z.

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ZEC (Post-Launch)

ZEC enters Z via the Z Bridge. The goal is for ZEC to arrive already shielded inside the ShieldedPool as private notes with no intermediate public address on Z. Bridge implementation details are in development. For the full bridge architecture, see Z Bridge.

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What Happens Inside

Private balances. Your balance is a commitment in a Merkle tree. No address-to-balance mapping exists on-chain. No block explorer shows your balance. Private transfers. Send assets to another ShieldedPool user without revealing who you are, who the recipient is, how much you sent, or which asset type you sent. An outside observer sees that a ShieldedPool transaction occurred. Nothing else. DeFi access via stealth address. When you want to trade on [[Z Trade]], borrow on [[Z Lend]], or interact with any ZApp, assets exit to a fresh one-time stealth address. You interact with DeFi from that address. Then assets reshield back into the ShieldedPool. The DeFi activity is visible on-chain but not linkable to you.

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How to Check Your Balance

Shielded balances are not readable from the chain directly. They are encrypted. Your wallet scans ShieldedPool event data and attempts decryption using your viewing key. Notes that belong to you decrypt successfully and your balance is derived. No one else can read the encrypted event data.

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How to Exit the ShieldedPool

To a stealth address for DeFi: The RelayAdapter pattern handles unshielding, executing the DeFi action, and reshielding output in one atomic transaction. To a plaintext address: Send assets from the ShieldedPool to any public address. The recipient address and amount are visible on-chain. The ShieldedPool origin of the funds is not revealed.

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Viewing Keys

A viewing key gives read-only access to your shielded transaction history without spending authority. Use cases include:

• Sharing with a tax accountant (scoped to the relevant fiscal year)
• Responding to a regulatory inquiry (scoped to specific transactions)
• Auditing by an institutional compliance team (full history within a time range)

What a viewing key reveals: complete transaction history within scope, all asset types and amounts, current shielded balances. What a viewing key cannot do: spend funds, view other users’ activity, modify or selectively omit transactions within scope. For how viewing keys work in compliance contexts, see Privacy and Compliance.

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Privacy Properties