Zero-Knowledge Consent: Auditable and Private Data Permission Management via Blockchain

Abstract

The challenge of achieving auditable, GDPR-compliant consent management while preserving true data subject privacy persists, as current blockchain-based solutions compromise anonymity through public ledgers. This paper addresses this by introducing a novel, privacy-by-design IT artefact built on the Ethereum platform that employs Zero-knowledge Succinct Non-Interactive ARgument of Knowledge (zk-SNARKs) to enable truly anonymous and irrefutable validation of data processing permissions. Implemented and evaluated through a Design Science Research (DSR) approach, the artefact demonstrated a high degree of functional and GDPR compliance, confirming its capacity to generate trustless, auditable on-chain proof of permission status. The proof of concept successfully implements core privacy-by-design principles through anonymity and encryption, with technical benchmarks indicating acceptable performance for the artefact's intended use despite the computational intensity of proof generation.