dnalob / contracts

contracts using boilerplate from semaphore protocol

ETH Bogota - Chain Statement - Smart Contract 📝

We are builidng our smart contract on top of Semaphore.

What is Semaphore 🐉

Semaphore is a zero-knowledge protocol that allows you to cast a signal (for example, a vote or endorsement) as a provable group member without revealing your identity. Additionally, it provides a simple mechanism to prevent double-signaling. Use cases include private voting, whistleblowing, anonymous DAOs and mixers.

Smart contract overview

We are refering to Semaphore boilerplate.

Smart Contracts:

1. ChainStatement.sol: Main logic of the code, includes adding user to group, verify proof, and set Relayer address.
2. BalanceGiver.sol: Mint tokens for users. (Testing purpose)
3. DummyToken.sol: General ERC20 Token. (Testing purpose)
4. Greeter.sol: Simple execution sample of using semaphore.

Key functionalities:

1. Add User To Group: function addNewUser(uint256 identityCommitment, address userAddr) external onlyRelayer
2. Create Proof that prove user exists in the group: generateProof(users[0].identity, group, BigInt(groupId), greeting, {wasmFilePath,zkeyFilePath })
3. Verify User is in the group: semaphore.verifyProof(groupId, merkleTreeRoot, signal, nullifierHash, groupId, proof)

General Workflow

1. Users connect their wallet and create identity in the Home Page ➡️ User's identity is registered on our contract.
2. Users enter the same identity information and generate Chain Statements in the Statements Page ➡️ Generate proof based on identity commitment and call verifyProof function from semaphore protocol.
3. If verified succeessfully, user can download their Chain Statement PDF ➡️ Chain Statement PDF stored on IPFS is fetched to the Front End.

Deployed Contract

Polygon Mumbai

Title	Address
Verifier20	0xbFA3E40AC6A75c1760130566E5b4DC5EB8890eaC
Poseidon library	0x56727656b869A48A4924596800020B9b500CB0fC
IncrementalBinaryTree library	0xA2CfB62dA0071bb4d57b4Aa64Cf920a35CA99fDD
Semaphore	0x206e2F907c54B49416CD4d26CFCdCa656E528dD2
ChainStatment	0x6f7cAf248770bA7dc49c6Fb13D1F10658758BED3

Optimism Goerli

Title	Address
Verifier20	0x2686540BE833cFB49F1D8BEa13F7c0E46767FC2D
Poseidon library	0xe9F49bE29195AFa0BDB483561D547C36f8be5045
IncrementalBinaryTree library	0x89168c3604B54EA33Ebf0477a36dA8766d5A5D98
Semaphore	0x08B2DB74922f00011F3404221cE3d9E6aAE1921D
ChainStatment	0x396064e93017c170477626830DCe671909146981

Start Building

1. Install packages: yarn add
2. Run the following commands sequentially in three separate tabs of the terminal:

yarn start:contracts

yarn start:web-app

yarn start:relay