⚠️Not maintained anymore, migrated here⚠️

On-chain Privacy DApp Demo

This demo showcases all the parts needed to create a privacy preserving DApp with good UX which are:

A circuit
A smart contract
A relayer
A webapp

On this example we do a simple anonymous message board but it can be extended for other DApps in other fields such as DeFi, voting & governance, identity, etc..

⭐Features

Feature	Supported
Aztec Noir circuit	✅
Solidity verifier	✅
ECDSA verification circuit	✅
EIP712 enabled	✅
Prover on browser (WASM)	✅
Ethers.js 6.9 relayer	✅
MIT license	✅

🚀How to launch

Step 1. Generate and deploy the Solidity verifier

Make sure you installed Nargo 0.19.4 as detailed below:

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/v0.19.4/nargo-x86_64-unknown-linux-gnu.tar.gz && \
tar -xvf $HOME/.nargo/bin/nargo-x86_64-unknown-linux-gnu.tar.gz -C $HOME/.nargo/bin/ && \
echo 'export PATH=$PATH:$HOME/.nargo/bin' >> ~/.bashrc && \
source ~/.bashrc

On MAC

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/v0.19.4/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

Now generate the Solidity verifier.

cd circuit
nargo codegen-verifier

This will generate a Solidity file located at circuit/contract/circuit/plonk_vk.sol. Deploy it on an EVM on-chain.

Step 2. Deploy the verifier contract

Now deploy the CommentVerifier contract located at contracts/CommentVerifier.sol. Pass the Verifier contract you just generated as constructor parameter.

Step 3. Launch the Relayer

Let's launch the relayer first. Fill the .env file based on .env.example on the relayer/ directory and run the following.

cd relayer
npm install
npm start

Setp 4. Launch the webapp and verify a proof

Open a new terminal and launch the webapp. Now fill the .env file based on .env.example on the webapp/, the run the following.

cd webapp
npm install
npm start

The webapp will automatically open on your browser. Now you will be able to generate proofs on your browser and send them to the relayer for on-chain verification.

⚠️Known issues (PRs welcome)

We need to compress the hashed message params to reduce L1 fees on L2s. We should use this and this

Turupawn/PrivacyDAppDemo