HashCloak

[ewynx]

Summary

This proposal describes the roadmap to implement Semaphore in Noir within 2 months. This requires a Noir circuit, additional SDK functionality that does proof generation and proof verification for the Noir circuit, and additional versions of the Semaphore Solidity contract where verifiers for UltraPlonk and UltraHonk are included. Lots of pieces have been (partially) worked on and we've gathered the necessary information to get started with this. With our experienced and motivated team, we'll be very happy to take on this project!

Team

HashCloak Inc. is a cryptography R&D lab and consultancy helping teams build secure, scalable, and privacy-preserving blockchain infrastructure. From advancing privacy tools to strengthening cryptographic security and optimizing blockchain performance, we bridge research and real-world deployment. Our expertise spans protocol design, cryptographic implementation, and audits, ensuring teams can confidently integrate cutting-edge cryptography into their systems.

The team assembled for this project consists of:

• Elena Fuentes (ewynx) - Cryptographic engineer. Has worked on noir-mpc-ml for NRG#2, zk-regex support for Noir and won 2nd prize for Best Noir App at ETHGlobal CircuitBreaker in 2023. Furthermore, she was part of the team that ported the Groth16, Plonk and Fflonk verifiers in snarkjs from Solidity to Sway (repo).
• Alex Liao (LYC386) - Cryptographic engineer. Has worked on Meson mixed network and developed a private account-abstraction wallet for it using circom. He was also part of the team that ported verifiers in snarkjs from Solidity to Sway (repo).
• Teresa Li - Project Manager. She has been part of the recent Noir-related work and will oversee the project. She was a speaker at NoirCon 0, sharing about the noir-mpc-ml project.

Timeline and Deliverables:

Deliverables:

1. Semaphore circuit in Noir with tests, using these test vectors to ensure correctness with the circom implementation.
2. Proof generation and verification for the SDK (code ref). Tests compatible with these tests.
3. Solidity implementations for UltraPLONK and UltraHONK verifiers that can be used with Semaphore.
4. Writeup that includes tutorial for devs who want to use this.
5. Benchmarks report: gatecount and proving times for the Noir circuit and gas cost estimation for the verifier contracts.
6. Final report with the details of our work.
7. Optimization for Noir circuits (If we have extra time).

Month 1:

• Implement the circuit in Noir with tests (testvectors). This uses the following elements:
  • Poseidon - available in Noir (docs ref)
  • BabyJubjub public key extraction, will need to implement this method. We can use the available scalar multiplication on the embedded curve in Noir (docs ref)
  • Binary Merkle Tree - The current implementation of Merkle Tree in zk-kit.noir is already for arity 2, so we can use it (code ref)
• Update SDK:
  • Proof generation in ts for both UltraPlonk and UltraHonk, using noirjs
  • Proof verification for both UltraPlonk and UltraHonk, using noirjs
  • Tests for all additions, following the existing tests
• Code reviews from both the PSE and Noir teams
• First progress report

Month 2:

• UltraPlonk and UltraHonk verifiers added to the contracts:
  • SemaphoreVerifier will need the version generated with bb: SemaphoreUltraPlonkVerifier.sol and SemaphoreUltraHonkVerifier.sol
  • tests
• Deployment and testing of contracts on Sepolia
• Benchmarks for circuit size, proving and verification time of the Noir circuit and gas cost estimation of the verifier contracts on Ethereum
• Write-up with tutorial on how to use the new functionality
• Code reviews from the Noir and PSE teams
• Optimizations for the Noir circuits if there's enough time
• Final report

Start Date

13 or 17 March 2025

Questions

• Should the Solidity verifier be for UltraHonk, UltraPlonk or both? (In the proposal, we assumed both)
• How should the Noir support exist, next to the circom support? E.g will this be a fork, will it exist along side the current functionality in -noir folders?
• Is it possible to have a code review each month?