ZK Face ID Wallet

An open-source, ERC-4337 wallet that lets users sign transactions with Face ID, eliminating the need for seed phrases.

How it works

Demo is live at https://noseedphrases.xyz.

First, we trigger a WebAuthn registration on the client's device, triggering a Face ID, Touch ID, or another supported authentication gesture. We ask it to sign a specific challenge string that indicates a possible transaction – for example, sending 0.1 ETH to vitalik.eth.

Next, we take the resulting ECDSA signature and public key and generate a ZK proof using the Halo2 proof system. Specifically, we build off of Axiom's halo2-ecc library, which has an implementation of an ECDSA proof on the secp256k1 curve. WebAuthn uses the secp256r1 curve, so we added its parameters and curve operations, published here.

Essentially, we're creating a proof that says, I have correctly performed Face ID and I authorize this transaction. And anyone who sees the proof will be able to verify it, and not gain any information about my secret key or personal data.

Finally, we'll need to send this proof to Ethereum to execute our transaction! We bundle a UserOperation and set the signature field to our zero-knowledge proof. We send the UserOperation to a bundler, where it's redirected to our P256Wallet smart contract wallet that verifies the proof and completes the transaction.

Future Application: Know Nothing Labs is currently building out a consumer application 👀

Roadmap

✅ Develop ZK circuits for proving secp256r1 elliptic curve based signatures used by the WebAuthn protocol

✅ Modify steps of the WebAuthn procedure to inject userop data into body signed by the WebAuthn authorizer's signature

✅ Build an account abstraction wallet which verifies proofs of valid WebAuthn signatures to validate userops

YOU ARE HERE👇
🏗️ Buidling a consumer app deeply integrated with our novel, easy to use wallet infra. Follow us at @knownothinglabs for more updates!

Links

Twitter: https://twitter.com/knownothinglabs
Demo: https://www.noseedphrases.xyz/
Github: https://github.com/zkwebauthn/webauthn-halo2