Quantum multiparty cryptosystems based on a homomorphic random basis encryption

Changbin Lu, Fuyou Miao, Junpeng Hou, Zhaofeng Su, Yan Xiong

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.