Noir on Scroll

Instalation

On Linux

mkdir -p $HOME/.nargo/bin && \
curl -o $HOME/.nargo/bin/nargo-x86_64-unknown-linux-gnu.tar.gz -L https://github.com/noir-lang/noir/releases/download/v0.22.0/nargo-x86_64-unknown-linux-gnu.tar.gz && \
tar -xvf $HOME/.nargo/bin/nargo-x86_64-unknown-linux-gnu.tar.gz -C $HOME/.nargo/bin/ && \
echo -e '\nexport PATH=$PATH:$HOME/.nargo/bin' >> ~/.bashrc && \
source ~/.bashrc

On MacOs Apple Silicon

mkdir -p $HOME/.nargo/bin && \
curl -o $HOME/.nargo/bin/nargo-aarch64-apple-darwin.tar.gz -L https://github.com/noir-lang/noir/releases/download/v0.22.0/nargo-aarch64-apple-darwin.tar.gz && \
tar -xvf $HOME/.nargo/bin/nargo-aarch64-apple-darwin.tar.gz -C $HOME/.nargo/bin/ && \
echo '\nexport PATH=$PATH:$HOME/.nargo/bin' >> ~/.zshrc && \
source ~/.zshrc

On MacOs Intel

mkdir -p $HOME/.nargo/bin && \
curl -o $HOME/.nargo/bin/nargo-x86_64-apple-darwin.tar.gz -L https://github.com/noir-lang/noir/releases/download/v0.22.0/nargo-x86_64-apple-darwin.tar.gz && \
tar -xvf $HOME/.nargo/bin/nargo-x86_64-apple-darwin.tar.gz -C $HOME/.nargo/bin/ && \
echo '\nexport PATH=$PATH:$HOME/.nargo/bin' >> ~/.zshrc && \
source ~/.zshrc

Generate a proof

Generate a new noir project and prepare it to receive the prover inputs.

nargo new hello_world
cd hello_world
nargo check

Now put the inputs in Prover.toml and generate the proof.

Prover.toml

x = "1"
y = "2"

nargo prove

The proof is now located at proofs/hello_world.proof.

Verify the proof

Generate the solidity verifier.

nargo codegen-verifier

The verifier contract is now located at contract/hello_world/plonk_vk.sol. Deploy it and send it's address as param to the following contract with custom logic.

// SPDX-License-Identifier: MIT

pragma solidity >=0.7.0 <0.9.0;

interface INoirVerifier {
    function verify(bytes calldata _proof, bytes32[] calldata _publicInputs) external view returns (bool);
}

contract NoirCustomLogic {
    INoirVerifier public noirVerifier;
    uint public publicInput;

    constructor(address noirVeriferAddress) {
        noirVerifier = INoirVerifier(noirVeriferAddress);
    }

    function sendProof(bytes calldata _proof, bytes32[] calldata _publicInputs) public {
        // ZK verification
        noirVerifier.verify(_proof, _publicInputs);

        // Your custom logic
        publicInput = uint(_publicInputs[0]);
    }
}

Nullifier

Circuit

use dep::std;

fn main(x: Field, y: pub Field) -> pub Field {
    assert(x != y);
    let hash = std::hash::pedersen_hash([x, y]);

    hash
}

nargo prove
nargo codegen-verifier

Solidity

// SPDX-License-Identifier: MIT

pragma solidity >=0.7.0 <0.9.0;

interface INoirVerifier {
    function verify(bytes calldata _proof, bytes32[] calldata _publicInputs) external view returns (bool);
}

contract NoirCustomLogic {
    INoirVerifier public noirVerifier;
    uint public publicInput;
    mapping(bytes32 => bool) public nullifiers;

    constructor(address noirVeriferAddress) {
        noirVerifier = INoirVerifier(noirVeriferAddress);
    }

    function sendProof(bytes calldata _proof, bytes32[] calldata _publicInputs) public {
        // ZK verification
        noirVerifier.verify(_proof, _publicInputs);

        // Your custom logic
        require(!nullifiers[_publicInputs[1]], "Proof already nullified");
        publicInput = uint(_publicInputs[0]);
        nullifiers[_publicInputs[1]] = true;
    }
}

Advanced zkDapp Demo

• Metamask compatibility
• Anonimity set merkle tree
• Node.js relayer
• Prover in browser

Github repo here.