On some efficiency aspects of the CKKS fully homomorphic encryption scheme

Fully homomorphic encryption (FHE) is a form of encryption that allows arbitrary computations on data without requiring to decrypt the ciphertexts. Among the diverse FHE schemes, CKKS is designed to efficiently perform computations on real numbers in an encrypted state. Interestingly, Drucker et al [J. Cryptol.] recently proposed an efficient strategy to use CKKS in a black-box manner to perform computations on binary data. In this talk, after an introduction on fully homomorphic encryption, I will explain how to modify CKKS to gain efficiency when handling binary data. As we will see, the obtained performance compares very favourably with that of the other FHE schemes. Based on joint work with Youngjin Bae, Jung Hee Cheon and Jaehyung Kim.