zuzalu-oracle v1.0.0

Zuzalu Oracle

This is a wrapper contract around the deploy contracts of Semaphore, to be used by Zuzalu.

How

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.

Deployed Addresses

• Sepolia

Building with Zuzalu Oracle

Understand the Semaphore Protocol

First, make sure you understand how the proof and group system works in Semaphore.

Check out their docs!

As an on-chain application

1. User visits the application's website
2. The application connects to the oracle and downloads the latest root of each group
3. 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
4. The website calculates a URL on the Zupass API for the group, given the latest root/group combination
5. The website invokes Zupass asking for a group membership with a group URL from step 4
6. The website extracts the semaphore proof from the returned PCD and uploads it to the smart contract
7. The smart contract verifies the semaphore proof, using the oracle, and depending on the return (true|false) it decides what to do

How to integrate in Solidity

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);

How to integrate in Typescript

1. yarn add zuzalu-oracle
2. 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();
...

License

MIT