Quantum multiparty cryptosystems based on a homomorphic random basis encryption

Abstract

Quantum information processing protocols have great advantages over their classical counterparts, especially on cryptography. Homomorphic encryption (HE) schemes enable processing encrypted data without decrypting them. In this paper, we study a quantum version of the HE scheme (iacr-ePrint/2019/1023) and improve it with flexible parties. Furthermore, we propose a threshold quantum secret scheme since multiparty cryptosystem is more practical due to its flexibility. These two schemes only require sequential decryption of quantum states. As a result, both schemes are information theoretically secure, perfectly correct and support homomorphism in a fully compact and non-interactive way. Finally, they are tested and verified on the IBM Q Experience platform.