This is a wrapper contract around the deploy contracts of Semaphore, to be used by Zuzalu.
The Zuzalu API offers the latest root for every group. A trusted backend cron service, named zuzalu-updater, reads that API call and updates the on-chain stored root, so that people can generate proofs and verify them on-chain.
First, make sure you understand how the proof and group system works in Semaphore.
Check out their docs!
- User visits the application's website
- The application connects to the oracle and downloads the latest root of each group
- The user wants to perform some on-chain activity that is gated to zuzalu groups members. The application selects the group the user will verify against
- The website calculates a URL on the Zupass API for the group, given the latest root/group combination
- The website invokes Zupass asking for a group membership with a group URL from step 4
- The website extracts the semaphore proof from the returned PCD and uploads it to the smart contract
- The smart contract verifies the semaphore proof, using the oracle, and depending on the return (true|false) it decides what to do
Read the smart contract docs!
Install
yarn add zuzalu-oracle
and then just
ZuzaluOracle oracle = ZuzaluOracle(ORACLE_ADDRESS);
uint[8] proof;
// Use the latest root of group Residents
oracle.verify(0, 0, 0, proof, ZuzaluOracle.Groups.Residents);
yarn add zuzalu-oracle- Import it as follows. The example is from zuzalu-updater
import { ZuzaluOracle__factory } from 'zuzalu-oracle';
export default {
async scheduled(
controller: ScheduledController,
env: Env,
ctx: ExecutionContext
): Promise<void> {
const provider = new ethers.JsonRpcProvider(env.ETH_RPC_URL);
const wallet = new ethers.Wallet(env.ETH_PRIVATE_KEY, provider);
const oracle = ZuzaluOracle__factory.connect(env.CONTRACT_ADDRESS, wallet);
const latestRoots = await oracle.getLastRoots();
...
MIT