Evaluation of somewhat homomorphic encryption schemes

Abstract

Homomorphic encryption allows one to outsource expensive computation to an untrusted party while keeping data in an encrypted form. While there has been a growing research focus in fully homomorphic encryption schemes, many real-world applications require a scheme to be only "somewhat" homomorphic. Somewhat homomorphic encryption (SWHE) schemes, which support a limited number of homomorphic operations before encountering a decryption failure, are much more efficient than their fully homomorphic counterparts. In this thesis, I present the empirical evaluation of two SWHE scheme prototypes built for IARPA's Security and Privacy Assurance Research (SPAR) program. The evaluation captures the exact performance costs of key generation, encryption, homomorphic evaluation, and decryption of each system using boolean circuits and inputs. In addition, I present the performance overhead of each system compared to a representative baseline, which evaluates the same set of circuits using unencrypted inputs.