Secure Multiparty Computation Based On Multi-key Full Homomorphic Encryption

With the development of cloud computing,people can conveniently perform various kinds of computing on the cloud,but the convenience also brings the risk of data leakage,the consequences of which are unpredictable.How to carry out secure computing under the condition of protecting data privacy has become a hot topic.Secure multi-party computation can allow people to calculate without revealing their own data,which meets the requirements of people's secure computation.Secure multi-party computation based on multi-key fully homomorphic encryption has always been an important branch in the research of secure multiparty computation.In this paper,two secure multi-party computation protocols based on fully homomorphic encryption are proposed,respectively as follows:1.Based on the multi-bit fully homomorphic encryption scheme proposed by Li Z P et al.,it is firstly proved that it has key homomorphic property,and the final decryption result is obtained by using threshold decryption.Then,a three-round secure multi-party computation protocol under the CRS model is constructed by using this scheme.The protocol can naturally resist the semi-malicious adversary,and can resist a malicious adversary under the noninteractive zero-knowledge proof.The security of the protocol is based on the lattices on the hard problem LWE variant of the hard problem Ferr-LWE and the some-are-errorless.LWE.Compared with the original scheme,it does not need complex ciphertext extension when it is extended to multi-key fully homomorphic encryption scheme.Compared with the traditional secure multi-party computation protocol based on fully homomorphic fully homomorphic encryption scheme,the efficiency can be improved obviously.2.Traditional secure multi-party computation protocols based on fully homomorphic encryption are all based on the CRS model,which to some extent limits the ability of each participant to generate the public key independently.In this paper,we design a three-round secure multi-party computation protocol without the CRS model.The protocol can resist a semimalicious adversary and the security is based on the difficult LWE problem on lattices.This paper uses the matrix coding technology,compared with the original scheme,both from the space efficiency and time efficiency are better than the original scheme,And reduce the decryption noise from 2(m4+m)mNB? to(2+m)mNB?.