Privacy Architecture

Traditional vs Privacy Multisig

Aspect	Traditional Multisig	PolyPay
Signer Identity	Public addresses stored on-chain	Hidden behind commitments
Who Signed	Visible to everyone	Commitment visible, EOA hidden

Commitment-Based Identity

Instead of storing addresses, PolyPay stores commitments (hash(secret, secret)):

• The secret is derived from signing a message with your wallet

• The commitment is stored on-chain in a signers list

• Only you know the secret that matches your commitment

How It Works

1. Setup: Each signer generates a secret and computes their commitment

2. Registration: Commitments are added to the smart contract's signers list

3. Signing: To approve a transaction, signers prove they know the secret for their commitment using ZK proofs

4. Verification: The smart contract checks if the commitment exists in the signers list

Privacy Model

When you sign a transaction:

• The ZK proof verifies you know the secret for your commitment

• The contract checks your commitment is in the authorized signers list

• Your Ethereum address (EOA) is never revealed on-chain

This means observers can see which commitment signed, but cannot link it back to your wallet address.

Relayer Privacy

In addition to ZK proofs, PolyPay uses a relayer wallet to enhance privacy further.

When signers call the smart contract directly, their wallet address is recorded as msg.sender on-chain. This partially reveals signer identity.

PolyPay's backend uses a dedicated relayer wallet to deploy accounts and execute transactions on behalf of users. Signers only submit ZK proofs to the backend (off-chain), and the relayer interacts with the blockchain.

Action	Without Relayer	With Relayer
Deploy account	Creator address exposed	Only relayer visible
Execute transaction	Executor address exposed	Only relayer visible

This creates complete EOA anonymity: no signer's Ethereum address ever appears on-chain.