Explanation and answers to critiques on: Blockchain-based Privacy-Preserving Record Linkage

The “Blockchain-based Privacy-Preserving Record Linkage—Enhancing Data Privacy in an Untrusted Environment” (BC-PPRL) uses Blockchain technology to provide accountability to the computation performed during the comparison step of PPRL. The BC-PPRL utilizes small fragments (splits) of the encoded records to iterative compute the similarity of the records and classify them into matches and non-matches, without sharing the complete information of the encoded records. Christen et al. propose a novel attack that leverages the exchanged information by the BC-PPRL. In this work, we acknowledge the Christen et al. findings and provide a detailed explanation of how the privacy of BB-PPRL could be compromised. We also make available a simplified version of the BC-PPRL, the datasets, and version (ported to python 3) of the attack that could be executed in the google cloud environment at: https://github.com/thiagonobrega/bcpprl-simplified.