blindr

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Inspiration

Managing private keys for cryptocurrency wallets poses significant risks, as losing your key means losing access to your funds. Recognizing the need for enhanced security, we explored shared custody solutions. However, existing methods compromise privacy by allowing custodians to see the user's funds. To address this, we aimed to create a service where a third-party custodian can assist in managing funds without compromising the user’s privacy. In fact, One of our team members worked at a company where they wanted this specific feature implemented because it is so useful. There is clear market demand.

What it Does

Our service introduces a novel approach to crypto wallet management by utilizing blind signatures and zero-knowledge proofs. This allows a third-party custodian to authorize transactions without knowing the transaction details or the funds themselves. It’s designed to ensure that even while assisting in the management of the wallet, the custodian remains unaware of the transaction's contents, thereby maximizing user privacy and security. Our system supports setting up withdrawal limits that are verified through zero-knowledge proofs, ensuring transactions comply without disclosing any sensitive information such as even the withdrawal limits themselves.

How We Built It

The backbone of our project is a combination of advanced cryptographic techniques and robust programming. We developed a zero-knowledge proof system in Rust to verify transaction properties, like adherence to withdrawal limits, without revealing the transaction itself. This is coupled with a backend custodian service, written in Python, which verifies these proofs and signs off on transactions blindly. To bridge these technologies, we created a Python wrapper around our Rust-based cryptographic components, facilitating (not so) seamless interaction between client requests and our secure backend, which is hosted on AWS.

Challenges We Ran Into

Integrating Rust and Python proved challenging, requiring us to modify existing libraries for blind signatures and zero-knowledge proofs to fit our architecture. Debugging the complex interactions between these components was time-consuming, and we’re still ironing out a few critical bugs.

Accomplishments We Are Proud Of

Bringing together complex cryptographic technologies to address a real-world need is our main achievement. Our project represents a significant step forward in privacy-centric crypto wallet management, proving that it's possible to combine security with convenience. This innovation not only meets a genuine market demand but also showcases our technical capabilities in creating a functional prototype under challenging conditions.

What’s Next for Our Project

Our immediate focus is on resolving the remaining bugs and enhancing the security features of our service. We are committed to refining our solution, ensuring it's robust and user-friendly for broader adoption. Future developments will also explore additional privacy-preserving features and expand the service’s capabilities to meet the evolving needs of the crypto community.

Built With

• cryptography
• flask
• python
• rds
• rust