​​MGP: Privacy Pools - v0.1
​​Past MolochDAO Privacy Grants
​​​+MGP 9.1: US$20,000 for BlockX to build a web UI for the Hopper mixer​ 
​​​+MGP 9.2: $2,000 for Koh Wei Jie for coordinating mixer development and funding​ 
​​​+MGP 19 - $2,500 for State of the Mixers Report​ 
​​​+MGP 21 - Tornado.Cash​ 
​​​+MGP 35—$10,000 for Tornado Cash Trusted Setup​ 
​​​+MGP 39—$40K for Tornado Cash Trusted Setup Audit​ 
​​In Defense of Privacy

​​Proposal

  • ​​$45K (40 ETH; +15% volatility buffer) for shipping a demo of permissioned privacy pools v0.1
  • ​​includes circuit code, smart contracts, JS libraries/scripts, and a demo UI
  • ​​target deployment to testnet + optimism, eta before EOY 2023
  • ​​ameen.eth to help transfer funds → 0x297BF847Dcb01f3e870515628b36EAbad491e5E8

​​Background

​​Vitalik explained on a recent podcast that it is possible to create a privacy pool where withdrawing users can optionally provide a ZK proof-of-exclusion that their deposit was not part of some subset of deposits. So as a user, if there are bad deposits that have been made from other bad addresses that I would prefer not to share an anonymity set with, I can opt to provide a ZK-proof along with my withdrawal that shows that my depositing address was not among those bad addresses. This is helpful because it allows users to share a ZK-circuit and smart contracts, without being forced to share an anonymity set.
​​
​​To demonstrate the feasibility of this approach, we aim to ship an experimental research version on a production EVM (probably Optimism).
​​
​​For further discussion, please see our eth research forum post. 
​​
​​Circuit Code Walkthrough (1.5h)
  • ​​ameen learns how zkp circuit programming works in this guided tour of the repo

​​Roadmap

  • ​​finish tests in privacy pools repo
  • ​​make basic JS libs for zkp
  • ​​refactor privacy pools to use new JS lib
  • ​​design & dev on UI
  • ​​write docs
  • ​​testnet deployment
  • ​​L2 deployment
​​

​​Specification

  • ​​circuits
  • ​​withdraw_from_subset.circom → main withdrawal merkle proof circuit
  • ​​verifier_templates
  • ​​withdraw_from_subset_verifier_template.sol → generates solidity verifier contract
  • ​​contracts
  • ​​verifiers
  • ​​ProofLib.sol → updated solidity base proofilb
  • ​​MerkleTree.sol → rewritten merkle tree, uses poseiden hash
  • ​​PrivacyPool.sol → deposit & withdraw
  • ​​scripts
  • ​​export_verifier.py → circuit setup for local testing
  • ​​js libraries
  • ​​zkp scripts → generate & verify proof for deposit & withdrawal
  • ​​UI libraries → generating & displaying & updating merkle trees
  • ​​contract tests