多密钥全同态加密研究

Overview on Multi-key Fully Homomorphic Encryption

多密钥全同态加密支持对不同用户(密钥)的密文数据进行分析处理,处理后的结果可由所有参与计算的用户联合解密,其相对于传统的(单密钥)全同态加密,更加适用于云环境下多用户数据的隐私保护和处理.此外,由于格密码自身具有的抗量子攻击特性,基于格的多密钥全同态加密成为近年来相关密码学者的研究热点.自2012年López-Alt等人提出多密钥全同态加密方案LTV12至今,多密钥全同态加密在传统的(单密钥)全同态加密的基础上蓬勃发展.本文从MKFHE的研究现状、MKFHE方案的典型构造、利用MKFHE来构造云环境下的安全多方计算(Multi-Party Computing,MPC)、当前MKFHE存在的问题以及未来发展趋势等方面,对近年来多密钥全同态加密的发展进行分析与研究.

Multi-key fully homomorphic encryption(MKFHE)can perform arbitrary operations on encrypted data under different public keys(users),and the final ciphertext can be jointly decrypted by all involved users.Comparing to traditional(single-key)FHE,MKFHE is more suitable to protect the privacy and secure processing of data in cloud computing environment.In addition,as latticebased cryptography is important alternative for post-quantum cryptography,lattice-based MKFHE has become a hotspot in recent years.Since López-Alt et al.proposed the first MKFHE scheme LTV12,MKFHE has continuous development on the basis of traditional(single-key)FHE.This paper presents a comprehensive overview and research on MKFHE following four aspects:the research status of MKFHE,the typical construction of MKFHE scheme,the typical construction of MPC protocol by MKFHE in cloud environment,the existing problems of MKFHE and the future development trend.