Encryption Performance Improvements of the Paillier Cryptosystem.

Abstract

Abstract. Homomorphic encryption methods provide a way to out-source computations to the cloud while protecting the confidentiality of the data. In order to deal with the large and growing data sets that are being processed nowadays, good encryption performance is an important step for practicality of homomorphic encryption methods. In this article, we study the encryption performance of the Paillier cryp-tosystem, a partially homomorphic cryptosystem that allows to perform sums on encrypted data without having to decrypt first. With a com-bination of both new and known methods, we increase the encryption performance by orders of magnitude compared to a näıve implementa-tion. The new methods reduce the bottleneck of noise calculation by using pre-computed noise to generate new noise in a much faster way than by using standard methods. 1