Distributed Differential Privacy with Byzantine Fault Tolerance

Abstract

This paper presents a novel approach to achieving both strong differential privacy guarantees and Byzantine fault tolerance (BFT) in distributed systems. The core of the system leverages a verifiable random function (VRF) based consensus protocol built upon a Byzantine fault-tolerant distributed ledger. This architecture effectively addresses the inherent challenges of protecting sensitive data while maintaining system availability and data integrity even in the presence of malicious actors. The system utilizes VRF to mask computation results, providing differential privacy, and the distributed ledger to ensure robustness against Byzantine attacks. The key innovation lies in the verifiable and layered design, offering a rigorous framework for combining these two traditionally disparate goals. We demonstrate a theoretical framework for the system's operation, outlining the protocols involved and the mathematical properties utilized to guarantee both privacy and fault tolerance. The system achieves a privacy parameter ε and a fault tolerance threshold τ, where ε controls the privacy loss and τ represents the level of Byzantine fault tolerance. The system's architecture is designed to be adaptable to various distributed applications, offering a robust solution for sensitive data processing in challenging environments.