zkp linear check

Overview

This repository demonstrates how to write, prove, and verify a simple Noir zero-knowledge circuit using the bb backend and a Solidity verifier.
It checks a basic arithmetic relation and showcases how to integrate Noir-generated proofs with Ethereum smart contracts.

---

✨ Introduction

An example repo to verify Noir circuits using:

• Noir (v1.0.0-beta.6) — to define and compile the circuit.
• bb (v0.84.0) — as the backend to generate the proof.
• Solidity — for on-chain verification of the proof.
• JavaScript — to orchestrate proof generation and export.

Folder Structure:

• /circuits – Contains the Noir circuits.
• /contract – A Foundry project with:
  • A Solidity verifier contract.
  • A test contract that reads the proof file and verifies it.
• /js – JavaScript scripts to:
  • Generate proofs.
  • Save them as JSON files compatible with Solidity.

---

🧠 Circuit Logic

The Noir circuit enforces the relation:

[ x \cdot 3 + y = \texttt{claimed_value} ]

Where:

• x: a private input (kept hidden in the proof).
• y: a public input.
• claimed_value: a public value to be validated against the computation.

This is a minimal example to illustrate how to prove knowledge of a private input involved in a linear arithmetic constraint and verify it on-chain.

---

✅ Tested With

• Noir: v1.0.0-beta.6
• bb: v0.84.0

🛠 Installation & Setup

# Clone the repo and pull submodules (e.g., for bb-solidity)
git submodule update --init --recursive

# Build circuits and generate the Solidity verifier
(cd circuits && ./build.sh)

# Install JavaScript dependencies
(cd js && yarn)

🧪 Proof Generation (JavaScript Workflow)

# Use bb.js to generate proof and save it to a file
(cd js && yarn generate-proof)

# Run Foundry test to read the generated proof and verify it
(cd contract && forge test --optimize --optimizer-runs 5000 --gas-report -vvv)

🔧 Proof Generation (CLI Workflow)

cd circuits

# Generate witness using nargo
nargo execute

# Generate proof with bb CLI
bb prove -b ./target/zkp_linear_check.json -w ./target/zkp_linear_check.gz -o ./target --oracle_hash keccak

# Run Foundry test to verify proof
cd ..
(cd contract && forge test --optimize --optimizer-runs 5000 --gas-report -vvv)

🔁 Dual Workflow Support: CLI & JavaScript

This project supports two parallel workflows for generating and verifying proofs:

• ✅ JavaScript-based workflow using bb.js and automated proof orchestration
• 🔧 Command-line workflow using nargo and bb directly

Choose the one that fits your stack or integration best.

---

🏗️ Building the Solidity Verifier

Run the build.sh script from the project root:

./build.sh

This will:

• Compile the Noir circuit using nargo
• Generate the verification key (vk)
• Export the Solidity verifier as contract/Verifier.sol

🧭 Ecosystem Attribution

This project is indexed in the Electric Capital Crypto Ecosystems Map.

Source: Electric Capital Crypto Ecosystems
Link: https://github.com/electric-capital/crypto-ecosystems
Logo:

💡 If you’re working in open source crypto, submit your repository here to be counted.

Thank you for contributing and for reading the contribution guide! ❤️