PriSearch: Efficient Search on Private Data

M. Sadegh Riazi, Ebrahim M. Songhori, Farinaz Koushanfar

Abstract: We propose PriSearch, a provably secure methodology for two-party string search. The scenario involves two parties, Alice (holding a query string) and Bob (holding a text), who wish to perform a string search while keeping both the query and the text private without relying on any third party. Such privacy-preserving string search avoids any data leakage when handling sensitive information, e.g., genomic data. PriSearch provides an efficient solution where two parties only need to interact for a constant number of rounds independent of the query and text size. Our approach is based on the provably secure Yao's Garbled Circuit (GC) protocol that requires the string search algorithm to be described as a Boolean circuit. We leverage logic synthesis tools to generate an optimized Boolean circuit for PriSearch such that it incurs the minimum communication/computation cost. We achieve approximately 2x and 140x performance improvements compared to the best prior non-GC and GC-based solutions, respectively.