System identification with binary-valued observations under both denial-of-service attacks and data tampering attacks:the optimality of attack strategy

With the development of wireless communication technology,cyber physical systems are applied in various fields such as industrial production and infrastructure,where lots of information exchange brings cyber security threats to the systems.From the perspective of system identification with binary-valued observations,we study the optimal attack problem when the system is subject to both denial of service attacks and data tampering attacks.The packet loss rate and the data tampering rate caused by the attack is given,and the estimation error is derived.Then the optimal attack strategy to maximize the identification error with the least energy is described as a min–max optimization problem with constraints.The explicit expression of the optimal attack strategy is obtained.Simulation examples are presented to verify the effectiveness of the main conclusions.

System identification with binary-valued observations under both denial-of-service attacks and data tampering attacks:defense scheme and its optimality

In this paper,we investigate the defense problem against the joint attacks of denial-of-service attacks and data tampering attacks in the framework of system identification with binary-valued observations.By estimating the key parameters of the joint attack and compensating them in the identification algorithm,a compensation-oriented defense scheme is proposed.Then the identification algorithm of system parameter is designed and is further proved to be consistent.The asymptotic normality of the algorithm is obtained,and on this basis,we propose the optimal defense scheme.Furthermore,the implementation of the optimal defense scheme is discussed.Finally,a simulation example is presented to verify the effectiveness of the main results.

Voting System Based on Blockchain

Online ballot box system has the advantages of high efficiency and environmental protection,but the existing network voting technology still has a lot of matter.Almost all electronic voting system could be proved to be intrusion.The administrator of the system could tamper with the data for benefit,and the system may be attacked by hackers.The safety and fairness of the existing network voting system depend entirely on the safety and credibility of the website itself,but these cannot guarantee the fairness of voting.Make full use of blockchain technology,so that voting,even if there are malicious participants,but also to ensure the correctness and safety of the vote.The introduction of block chain technology,block chain has decentralized,data tampering and other characteristics.P2P network is applied in the block chain layer to construct a distributed database,digital signature algorithm and encryption technology are used to ensure that the data cannot be tampered with,consensus network algorithm is used to ensure the consistency of the data in the network,and timestamp technology is applied to save the data blocks in a chain structure connected end to end.It paper focuses on the implementation of P2P network networking mode,node block synchronization,data and block verification mechanism and consensus mechanism to ensure data consistency in the network layer of block chain layer.Using time stamp,Merkle tree,asymmetric encryption and other technologies to design data blocks and use chain structure to store data blocks.Combined with the characteristics of blockchain,a fair and transparent voting system is constructed.Model aims to apply the block chain technology to the voting scenario and design a secure block chain voting architecture.It system is designed and developed based on the block chain system.It makes full use of its decentralization,removes the dependence of electronic voting on trusted third parties,and protects the privacy of voters and candidates.Data cannot be tampered with.Once the data are stored in the block chain,it cannot be tampered with.It provides a real and credible database.