ZK11: Aptos Keyless: Blockchain Accounts without Secret Keys - Alin Tomescu

Summary

Alen from Aptos Labs introduces Aptos Keyless Accounts, a blockchain account system that eliminates the need for secret keys. By tying account security to traditional web accounts like Google, it aims to simplify onboarding for new users and enhance user experience. Keyless accounts address common issues with current blockchain UX, such as the complexity of wallet installation, mnemonic phrase management, and device transfer difficulties. Alen discusses the technical implementation, including the use of OpenID Connect signatures and zero-knowledge proofs for privacy, and touches on future improvements and challenges.

Takeaways

• 🔐 **Keyless Accounts**: Aptos introduces keyless accounts, a blockchain account system that doesn't require secret keys, aiming to simplify user onboarding.
• 🌐 **Web Account Integration**: Security is based on traditional web accounts like Google, Facebook, or Apple, making it familiar to users.
• 👥 **Joint Work**: The keyless account system is a collaboration between Aptos Labs' core team and Geometry Research.
• 🚀 **User Experience Focus**: The goal is to onboard the next billion users by making the process of joining blockchain spaces easier.
• 📱 **Simplifying DApp Interaction**: Users shouldn't need to install wallets or deal with transaction prompts, making the experience seamless across devices.
• 🔗 **App-Specific Accounts**: Keyless accounts are tied to specific apps, preventing malicious sites from stealing accounts associated with different DApps.
• 🖊️ **Transaction Signatures**: Transactions are signed using an Open ID Connect signature from providers like Google, ensuring security.
• 🙈 **Privacy Preservation**: Zero-knowledge proofs are used to hide sensitive information such as email addresses and application IDs from the blockchain.
• 🔄 **Ephemeral Key Pairs**: To improve performance, users generate an ephemeral key pair for each transaction, signed by Google, reducing the need for zero-knowledge proofs per transaction.
• 🌶️ **Pepper Service**: A pepper service is introduced to handle the blinding factor for account addresses, enhancing privacy and security.
• 🔄 **Recovery Mechanisms**: Keyless accounts have recovery mechanisms in case the signature provider is unavailable, such as using an email signature to rotate keys.

Q & A

What is Aptos Keyless Accounts?

Aptos Keyless Accounts are blockchain accounts that eliminate the need for secret keys. They derive their security from traditional web accounts like Google or Facebook, making onboarding easier for users.

Who is Alen and what is his role at Aptos Labs?

Alen is the head of cryptography at Aptos Labs. He is responsible for the development and security of cryptographic systems within the organization.

What is the main goal of implementing Keyless Accounts?

The main goal is to onboard the next billion users by simplifying the user experience and eliminating the need for users to manage secret keys or mnemonic phrases.

How does the user experience improve with Keyless Accounts?

Users can directly sign up for a dApp without installing extra software, and they don't need to write down mnemonic phrases. This simplifies the process of interacting with blockchain applications.

What is the role of OpenID Connect (OIDC) in Keyless Accounts?

OIDC is used to sign transactions on behalf of the user. It allows the user's email address and the application ID to be signed by a trusted provider like Google, creating a secure and verifiable signature.

How does the privacy of users' email addresses and application IDs get protected?

Privacy is maintained by using zero-knowledge proofs. This ensures that sensitive information like email addresses and application IDs are not revealed to the blockchain validators.

What is a prover service and how does it relate to Keyless Accounts?

A prover service is used to speed up the computation of zero-knowledge proofs, which are necessary for the privacy-preserving aspects of Keyless Accounts. It helps in verifying transactions quickly.

What is the pepper service and how does it contribute to Keyless Accounts?

The pepper service helps users remember their pepper, which is a blinding factor used to generate blockchain addresses. It ensures that the address is not directly derived from the email address and client ID, adding an extra layer of privacy.

How does the implementation of Keyless Accounts ensure performance?

The implementation uses GR16 over a fast curve and circom to ensure that the verification time for keyless transactions is minimal and the proof size is small.

What are some potential issues with the current Keyless Accounts system?

Some potential issues include the reliance on third-party providers for signatures, the need for a recovery mechanism in case the signature provider goes down, and the potential for the prover service to leak privacy.

What are some future improvements planned for Keyless Accounts?

Future improvements include moving the pepper service on top of the validator for better security, potentially moving the trusted setup onto the validator, and working on faster proving to eliminate the need for a prover service.