Secure Hamming Distance Based Computation and Its Applications

This paper examines secure two-party computation of functions which depend only on the Hamming distance of the inputs of the two parties. We present efficient protocols for computing these functions. In particular, we present protocols which are secure in the sense of full simulatability against malicious adversaries. We show different applications of this family of functions, including a protocol we call m-point-SPIR, which is all efficient variant of symmetric private information retrieval (SPIR). It can be used if the server's database contains N entries, at most N/log N of which have individual values, and the rest are set to some default value. This variant of PIR is unique since it can be based on the existence of OT alone.