(2026-05) YsPIR; HE-Based Single-Server Private Information Retrieval with Low Communication Cost and High Throughput
2026-05-14
We introduce YsPIR, a single-server private information retrieval (PIR) protocol that improves upon the state-of-the-art KsPIR protocol by Luo, Liu, and Wang (CCS 2024) in server response time and offline communication. YsPIR is built on a new first-dimension folding technique, which reduces online computation time and decreases the public-key material required in the offline phase.
Our approach has three main advantages. First, it enables the most resource-intensive computations to be preprocessed offline, thereby reducing online response time. Second, its offline communication is independent of the database size and remains small. Third, it maintains low communication cost even under high-throughput settings.
We conduct comprehensive experiments to evaluate the concrete performance of YsPIR. The results show that YsPIR achieves approximately 1.64x higher online throughput and reduces offline communication by about 3.09x compared with KsPIR.