FHEW with efficient multibit bootstrapping

Abstract

In this paper, we describe a generalization of the fully homomorphic encryption scheme FHEW described by Ducas and Micciancio [8]. It is characterized by an efficient bootstrapping procedure performed after each gate, as opposed to the HElib of Halevi and Shoup that handles batches of encryptions periodically. While the Ducas-Micciancio scheme was limited to NAND gates, we propose a generalization that can handle arbitrary gates for only one call to the bootstrapping procedure. We also show how bootstrapping can be parallelized and address its performances in a multicore environment.