Research On New Cryptographic Protocols For Privacy Protection

With the continuous progress of science and technology,communication devices such as mobile intelligent terminals and sensors have achieved rapid development,and information about what people eat,what people wear,where people live,what transportation people take and how people socialize has been digitized.People use sensors,mobile intelligent terminals and other technologies to collect,transmit and get access to data information instantly.The sustainable and rapid growth in the size and variety of data in human society also exacerbates the problem of information security and privacy protection.In order to protect the security of data and the privacy of users,research on technologies of location privacy protection,cloud computing services privacy protection and quantum-based privacy protection is conducted in this thesis,and it includes the following aspects:Aiming at the problem of central server leakage in location privacy protection,a location privacy protection protocol of attribute-based PIR is proposed.Using attribute-based encryption algorithm and the special nature of location privacy service,a privacy information retrieval protocol with zero knowledge disclosure is established.By deploying three different algorithms on LBS server and client,the protocol completes the query feedback which can protect the privacy query information.The proposed protocol is theoretically analyzed through security and performance analysis and further verifies the superiority of this proposed algorithm by comparison and comparative experiments of similar algorithms.The analysis shows that this protocol can provide fast query retrieval speed.Aiming at the problem of data privacy of cloud computing services,a lattice-based fully homomorphic signature protocol and a lattice-based fully homomorphic encryption protocol are proposed based on the GPV protocol.In the signature protocol,anyone can use the public key to publicly verify and support the off-line allocation operation without knowing the original signature data,which greatly improves the verification speed of the signature.At the same time,the growth rate of signature size is optimized.In the encryption protocol,by using a simple error structure to construct the key conversion algorithm,reliable security of the protocol is demonstrated through the security analysis.In order to further improve the efficiency of lattice-based fully homomorphic encryption protocols,two more efficient lattice-based fully homomorphic encryption protocols are proposed.Firstly,the BGV12 protocol and GSW protocol are analyzed.Then,by optimizing noise increasing problem in the key switching stage,based on the D-LWE problem,the BGV12 protocol is improved.Therefore,a more efficient fully homomorphic encryption protocol is proposed.Also,it is proved that under the assumption of D-LWE hardness,the protocol is secure under chosen-plaintext attack.In addition,the GSW protocol is improved by message packaging technology,and the matrix GSW fully homomorphic encryption protocol is proposed to further improve the operating efficiency of the protocol.By using quantum algorithms,two privacy-preserving cryptographic protocols that do not depend on mathematical theory are proposed.Firstly,by using single particle and phase encryption,an efficient quantum secrecy comparison protocol based on Circle model is designed,which can resist external attack,participant attack and semi-honest third-party attack.In addition,an efficient quantum voting protocol based on special quantum orthogonal quadrature DC states is designed by using quantum entanglement,quantum superposition and quantum teleportation.The protocol cannot only satisfy the legitimacy of voting and the blindness,anonymity,fairness,integrity and non-repeatability of signatures,but also resist known quantum attacks,denial of service attacks,joint attacks,interception retransmission attacks and post-quantum attacks.After theoretical derivation and experimental verification,it is proved that these new cryptographic protocols can better protect privacy information and data security.