Research On Data Aggregation Scheme Of Privacy Protection In Smart Grid

In smart grid,through collecting and analyzing users’ near-real-time power consumption data,the control center(CC)can effectively monitor and predict the operating status of the power grid,and thereby improve the safety and reliability of the power grid system.However,while analyzing and processing power consumption data,the problem of users’ privacy leakage arises.For example,through analyzing the user’s power consumption data in various time periods,an attacker can easily infer his/her daily habits.Therefore,there is an urgent need for a cryptographic solution that can collect users’ near-real-time power consumption data and provide users with privacy protection.Considering that the data aggregation technology combined with homomorphic encryption can hide the detailed power consumption information of individual users in the data collection process,this technology has been widely used in smart grids to provide users with privacy protection.Unfortunately,the performance of existing data aggregation schemes in terms of fine-grained analysis,computational cost,or communication overhead is not satisfactory.In response to these issues,the main work of this thesis is listed as follows:1.A composite order elliptic curve based efficient multidimensional data aggregation scheme is proposed.Most of the existing data aggregation schemes only support single-dimensional data aggregation,which makes the CC ultimately only be able to obtain the sum of the electricity consumption of all users,so they cannot meet the demands of the CC for fine-grained analysis of users’ data.For this reason,some multi-dimensional data aggregation schemes that can collect the power consumption data of different types of appliances in users’ homes have been proposed.However,the performance of these solutions in terms of computational cost or communication overhead makes them unsuitable for use in smart grid environments where computing and communication resources are limited.In response to the above problems,we first extend the EC-El Gamal cryptosystem and then propose a composite order elliptic curve based El Gamal encryption algorithm that supports large plaintext spaces and has additive homomorphism.Not only that,it also inherits many advantages of elliptic curve cryptography,and can be used in smart grid to encrypt multi-dimensional electricity consumption data of users.Then,through using the proposed encryption algorithm,a composite order elliptic curve based efficient multidimensional data aggregation scheme is proposed.Compared with the existing scheme,our scheme can facilitate the fine-grained data analysis of the CC,and effectively reduce the calculation and communication overheads caused by data encryption and ciphertext transmission,respectively.2.An efficient data aggregation scheme that supports privacy protection and function query is proposed.In the existing data aggregation scheme that support function query,although the collection and function query of power consumption data can be implemented in a privacy-protected manner,there is a problem of excessive computation,communication,and storage overheads.For this reason,we first propose an elliptic curve El Gamal encryption algorithm with a double trapdoor decryption mechanism.Then,using the proposed encryption algorithm and the elliptic curve Schnorr signature scheme,an efficient data aggregation scheme supporting privacy protection and function query is proposed for the smart grid.The scheme can effectively reduce the computational overhead of smart meter encryption and signature and fog node signature verification and the cost of data communication and storage,as well as support the CC and users to launch various function queries on encrypted power consumption data.However,considering that the CC needs to perform a large number of decryption operations during the function query,but the decryption efficiency of the above encryption algorithm is low,so complex function query on the encrypted data may bring it a heavy calculation burden.In response to this problem,another El Gamal-OU cryptosystem is proposed to improve the decryption efficiency of the CC,which also has a double trapdoor decryption mechanism.Compared with the BCP cryptosystem used in the existing scheme,it also has great advantages in terms of encryption and decryption efficiency and ciphertext length.