P-signature-based blocking to improve the scalability of privacy-preserving record linkage

Integrating data from multiple sources with the aim to identify records that correspond to the same entity is required in many real-world applications including healthcare, national security, businesses, and government services. However, privacy and confidentiality concerns impede the sharing of personal identifying values to conduct linkage across different organizations. Privacy-preserving record linkage (PPRL) techniques have been developed to tackle this problem by performing clustering based on the similarity between encoded record values, such that each cluster contains (similar) records corresponding to one single entity. When employing PPRL on databases from multiple parties, one major challenge is the prohibitively large number of similarity comparisons required for clustering, especially when the number and size of databases are large. While there have been several private blocking methods proposed to reduce the number of comparisons, they fall short in providing an efficient and effective solution for linking multiple large databases. Further, all private blocking methods are largely dependent on data. In this paper, we propose a novel private blocking method addressing the shortcomings of existing methods for efficiently linking multiple databases by exploiting the data characteristics in the form of probabilistic signatures, and we introduce a local blocking evaluation framework for locally validating blocking methods without knowing the ground-truth data. Experimental results on large datasets show the efficacy of our method in comparison to several state-of-the-art methods.