A Redactable Blockchain Architecture for Regulatory Compliance

Abstract

Redactable blockchains enable controlled removal or modification of data to meet regulatory demands, but existing solutions often sacrifice decentralization or auditability. This paper presents a redactable blockchain architecture that combines a Redaction Policy Engine (RPE), multi-party validator voting, and post-quantum chameleon hash functions. We introduce a structured lifecycle—from submission and policy validation to execution and logging—anchored by cryptographic enforcement and on-chain governance. Our design supports GDPR-aligned features such as audit trails, user appeals, and purpose limitation enforcement. Implemented on a permissioned Ethereum network, our system demonstrates lower latency (1.82s), gas cost (128.5k), and storage overhead (1.2%) compared to prior solutions. A detailed security and compliance analysis confirms resilience against validator collusion and quantum threats. This work offers a practical framework for deploying redactable blockchains in regulated environments while preserving verifiability and decentralization.