Decentralized Inverse Transparency with Blockchain, Valentin Zieglmeier (TUM)

Talk given by Valentin Zieglmeier (TUM)
Abstract: Inverse transparency aims to protect employees from misusage of their data by making all access visible to them. This necessitates a trusted log to establish a non-repudiable timeline of events. The unique properties of blockchain facilitate this by providing immutability and availability. For power asymmetric environments such as the workplace, permissionless blockchain is especially beneficial as no trusted third party is required. Yet, two issues remain: (1) If a central arbiter facilitates exchanges, they could manipulate the log. Therefore, we need to guarantee non-repudiable data exchange in a decentralized setting. (2) With data governed by the GDPR, blockchain’s immutability and transparency become a liability. After a rightful request, individual’s data need to be rectified or deleted. And only those with justified interest should be able to read the personal data stored in the blockchain.
To solve these issues, we present Kovacs, a decentralized data exchange and usage logging system for inverse transparency built on blockchain. Its new-usage protocol ensures non-repudiation, and therefore accountability, for inverse transparency. Its one-time pseudonym generation algorithm guarantees unlinkability and enables proof of ownership, which allows data subjects to exercise their legal rights regarding their personal data. Importantly, it can be used with any blockchain software and is fully decentralized.