Messaging with Purpose Limitation -Privacy-Compliant Publish-Subscribe Systems

• Published in: 2021 IEEE 25th International Enterprise Distributed Object Computing Conference (EDOC) pp. 162 - 172
• Main Authors: Wolf, Karl, Pallas, Frank, Tai, Stefan
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-10-2021
• Subjects: Access control; Data privacy; Distributed databases; GDPR; Law; messaging; Privacy; privacy engineering; Publish-subscribe; Publishing; purpose limitation
• ISSN: 2325-6362
• DOI: 10.1109/EDOC52215.2021.00027

Purpose limitation is an important privacy principle to ensure that personal data may only be used for the declared purposes it was originally collected for. Ensuring compliance with respective privacy regulations like the GDPR, which codify purpose limitation as an obligation, consequently, is a major challenge in real-world enterprise systems. Technical solutions under the umbrella of purpose-based access control (PBAC), however, focus mostly on data being held at-rest in databases, while PBAC for communication and publish-subscribe messaging in particular has received only little attention. In this paper, we argue for PBAC to be also applied to data-in-transit and introduce and study a concrete proof-of-concept implementation, which extends a popular MQTT message broker with purpose limitation. On this basis, purpose limitation as a core privacy principle can be addressed in enterprise IoT and message-driven integration architectures that do not focus on databases but event-driven communication and integration instead.