Privacy Pools

This repository implements a privacy pool based on the Privacy Pools Paper. The project leverages Circom circuits, Starknet, and Groth16 for zero-knowledge proof-based transactions, offering private and anonymous financial operations.

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Requirements

This repository uses asdf for managing tool versions. Ensure you have asdf installed before proceeding.

Tool Versions

The following tools and versions are required:

• Python: 3.10.16
• Node.js: 23.5.0
• Scarb: 2.9.1
• Starknet Foundry: 0.35.1

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Setup Instructions

1. Clone the repository:

   git clone git@github.com:EkuboProtocol/privacy-pools.git
   cd privacy-pools

2. Install dependencies using asdf:

   asdf install

3. Set up the Python environment:

   python -m venv .venv
   source .venv/bin/activate
   pip install -r requirements.txt

4. Compile the Circom circuit:

   mkdir -p target
   circom circuits/pool.circom --r1cs --wasm --sym --c --output target

5. Generate trusted setup and keys:

   npx snarkjs powersoftau new bn128 16 target/pot16_0000.ptau
   npx snarkjs powersoftau contribute target/pot16_0000.ptau target/pot16_0001.ptau --name="First contribution"
   npx snarkjs powersoftau prepare phase2 target/pot16_0001.ptau target/pot16_final.ptau
   npx snarkjs groth16 setup target/pool.r1cs target/pot16_final.ptau target/pool_0000.zkey
   npx snarkjs zkey contribute target/pool_0000.zkey target/pool_0001.zkey --name="1st Contributor Name"
   npx snarkjs zkey export verificationkey target/pool_0001.zkey target/verification_key.json
   npx snarkjs zkey export solidityverifier target/pool_0001.zkey target/verifier.sol

6. Generate verifier constants and integrate:

   garaga gen --project-name verifier --system groth16 --vk target/verification_key.json
   cp verifier/src/groth16_verifier_constants.cairo pool/src/verifier/groth16_verifier_constants.cairo

7. Build the project:

   scarb build

8. Run tests:

   cargo test

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Running the Example

To demonstrate the functionality, follow these steps:

1. Start a local Starknet development environment:

   starknet-devnet --seed 0

2. Declare and deploy contracts:

   sncast declare --contract-name ERC20Upgradeable
   sncast declare --contract-name UniversalECIP
   sncast declare --contract-name Groth16VerifierBN254
   sncast declare --contract-name Pool
   
   sncast deploy --class-hash <hash> --constructor-calldata <calldata>

3. Perform operations:

   • Approve token transfers:

     sncast invoke --contract-address <address> --function approve --calldata <calldata>

   • Run Association Set Provider:

     cargo run -p asp -- --contract-address <pool-address>

   • Deposit funds:

     cargo run -p cli -- deposit --pool-address <pool-address> --secret <secret> --nullifier <nullifier> --amount <amount>

   • Withdraw funds:

     cargo run -p cli -- withdraw --pool-address <pool-address> --secret <secret> --nullifier <nullifier> --amount <amount> --refund-secret <refund-secret> --refund-nullifier <refund-nullifier> --refund-amount <refund-amount> --recipient <recipient-address> --merkle-tree-root <merkle-tree-root> --fee <fee>

   • Query balance:

     sncast call --contract-address <address> --function balance_of --calldata <calldata>

4. Withdraw fees:

   sncast invoke --contract-address <pool-address> --function withdraw_fee --calldata <calldata>

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Contribution

Contributions are welcome! Please follow the standard GitHub flow: fork, branch, commit, and open a pull request.

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License

This project is licensed under the MIT License. See the LICENSE file for details.