noir-psymm

A project integrating pSymm contract with Noir ZK circuits for enhanced privacy.

Circuits

• ATC (address to custody) - deposit funds to pSymm.
• CTC (custody to custody) - split/anonymize funds between pSymm custodies (without disclosing original commitment)
  • Current problem: mismatch of merkle tree root between Noir and Solidity, fixed temporarily with setRoot.
• CTA (custody to address) - withdraw funds from pSymm. Currently not implemented.

Installation

1. Install JavaScript dependencies:

   yarn install

2. Install Noir and the Barretenberg (BB) proving backend by following official documentation.

Testing noir-psymm

Run the test suite with:

yarn hardhat test contracts/test/noirPsymm

How to integrate a new Noir circuit

To create a new circuit (e.g., CTA based on ATC):

1. Copy an existing circuit as a template:

   cp -r noir/pSymmATC noir/pSymmCTA
   cd noir/pSymmCTA

2. Modify the circuit:

   • Update the circuit name in Nargo.toml
   • Make necessary modifications to src/main.nr

3. Compile the circuit:

   nargo compile

   This will generate target/pSymmCTA.json

4. Generate the verifier contract:

   bb write_vk -b target/pSymmCTA.json
   bb contract

   The contract will be generated at target/contract.sol

5. Copy the verifier contract to the contracts directory:

   cp target/contract.sol ../../contracts/src/noirPsymm/VerifierCTA.sol

Current Issues

The merkle root generated by the Noir CTC circuit and JavaScript doesn't match the one generated in Solidity contract.