CCA1 secure FHE from PIO,revisited  

作　　者：Biao Wang Xueqing Wang Rui Xue 

机构地区：[1]State Key Laboratory of Information Security,Institute of Information Engineering,Chinese Academy of Sciences,Beijing 100093,China [2]School of Cyber Security,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Cybersecurity》2018年第1期222-229,共8页网络空间安全科学与技术（英文）

基　　金：supported by National Natural Science Foundation of China[grant number 61472414,61772514,61602061];National Key R&D Program of China(2017YFB1400700).

摘　　要：Fully homomorphic encryption(FHE)is a powerful cryptographic primitive that allows anyone to compute on encrypted data using only public information.So far,most FHE schemes are CPA secure.In PKC 2017,Canetti et al.extended the generic transformation of Boneh,Canetti,Halevi and Katz to turn any multi-key identity-based FHE scheme into a CCA1-secure FHE scheme.Their main construction of multi-key identity-based FHE is from probabilistic indistinguishability obfuscation(PIO)and statistical trapdoor encryption.We show that the above multi-key identity-based FHE is not secure by giving an attack.Then we give a solution to avoid the attack and redesign a more succinct and efficient multi-key identity-based FHE scheme.Compared with the scheme of Canetti et al.,ours has smaller secret key of one identity and more efficient homomorphic operations.Thus we obtain a more efficient CCA1 secure FHE scheme.

关 键 词：Fully homomorphic encryption CCA1 Probabilistic indistinguishability obfuscation 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]