Civic Gateway Tokens on Ethereum blockchain

This repository contains set of Ethereum smart contracts for Civic On-chain Identity Gateway token system.

Gateway tokens allows Ethereum DeFi projects to validate that their users successfully completed KYC, with regulations and guidances from FATF, US OFAC, US OCC BSA and others.

Quick Start

1. Use established node version by running nvm use
2. Install repository dependencies by running yarn install
3. Run yarn build to compile smart contracts
4. Execute yarn test to run the tests.

Static analysis

Additionally, you can perform static analysis for well-known code issues and vulnerabilities using Slither.

pip3 install slither-analyzer
yarn analyze

Environment variables

Please refer to .env.example and create .env to provide secret info such as private keys, Infura ID. Private keys are used in order to deploy smart contracts on one of the Ethereum networks.

Compile

To compile smart contracts, type hardhat compile. Use --force option to recompile everything if needed.

The compiled output is a json file called Artifacts and saved in ./build/contracts directory per contract basis. ABI and bytecode associated with the smart contract will be saved in the json file.

Deployment

In order to deploy the protocol please execute yarn deploy <NETWORK> command and replace with the network you want to deploy the protocol.

For example yarn deploy hardhat will deploy the protocol on the local hardhat version of the ethereum blockchain.

After the successful deployment you'll be able to find the deployment result in the deployments folder.

Integration

To integrate Gateway in your smart contract:

First, import the contract dependencies:

npm install @civic/gateway-protocol-eth

Then, in your smart contract, inherit the Gated contract, and add the gated modifier to any function.

The function can only be called by a msg.sender that has a valid gateway token.

import '@civic/gateway-protocol-eth/contracts/Gated.sol';

// Your contract
contract MyContract is Gated {
  constructor(address gatewayTokenContract, uint256 gatekeeperNetwork) Gated(gatewayTokenContract, gatekeeperNetwork) {}

  function myFunction() external gated {}
}

If you want more control over the verification process on-chain, you can use the following code instead of the Gated contract:

import "@civic/gateway-protocol-eth/contracts/interfaces/IGatewayTokenVerifier.sol";

...
IGatewayTokenVerifier verifier = IGatewayTokenVerifier(gatewayTokenContract);
if (!verifier.verifyToken(addressToVerify, gatekeeperNetwork)) {
// some logic
}

Creating a Gatekeeper Network

This section describes how to create a Gatekeeper Network (GKN) and add Gatekeepers to it. It uses ethers to interact with the smart contracts.

// check slot ID availability
const slotId = ...; // select a slot ID
const network = await gatewayToken.getNetwork(slotId);

// create a gatekeeper network, owned by the wallet (the wallet is the network authority)
await gatewayToken.connect(wallet).createNetwork(slotId, 'My Gatekeeper Network', false, ZERO_ADDRESS);

// create a gatekeeper network, owned by a DAO
await gatewayToken.connect(wallet).createNetwork(slotId, 'My Gatekeeper Network', true, DAO_ADDRESS);

Adding a Gatekeeper to the GKN

// add a gatekeeper to the network
await gatewayToken.connect(wallet).addGatekeeper(gatekeeperAddress, slotId);

Setting a network feature

Only one network feature is available:

• removeGatekeeperInvalidatesTokensFeature - if set, removing a gatekeeper from the network will invalidate all gateway tokens issued by the network.

const removeGatekeeperInvalidatesTokensFeature = 0;
const mask = 1 << removeGatekeeperInvalidatesTokensFeature;

// will be false
await gatewayToken.networkHasFeature(slotId, removeGatekeeperInvalidatesTokensFeature);

await gatewayToken.connect(identityCom).setNetworkFeatures(slotId, mask);

// will be true
await gatewayToken.networkHasFeature(slotId, removeGatekeeperInvalidatesTokensFeature);