Research And Implementation Of The Complex Query Statements In Encrypted Database

The rapid development of network technology and information technology makes the data exploding,leading to the big data in the digital and informational era becoming the catalyst for social development.However,the traditional local storage mode in the storage and processing of massive data appears to be stretched,especially for the relational database,such as data volume being limited by storage media,high cost of labor maintenance,poor scalability of the system,etc.With the development of cloud computing technology,cloud storage can solve these problems with the advantages of flexible system expansion,convenient infrastructure deployment and unlimited storage.Individuals,enterprises,government agencies and other units can't afford the storage and computation overhead of big data,therefore gradually outsource the data to cloud platforms for storage and processing.However,traditional research work stores data in plaintext within the cloud relational databases.Database administrators,hacker attackers,and outsourced third-party auditors can all obtain data stored in the cloud,which greatly increases the likelihood of data leakage.The criminals may use leaked data information for malicious fraud and other acts,resulting in unnecessary trouble or economic loss.Data leakage has become an important issue to be solved in the field of cloud storage.At the same time,the existing research based on ciphertext queries mainly focuses on the implementation of simple query statements,which can't meet the requirement of practical application.In order to realize the expansion of ciphertext query statements in relational databases,this paper proposes the research and implementation of complex query statements in encrypted databases.The major research efforts involves four aspects as follows:1.Taking the data leakage of relational database as a whole starting point,this paper studies the feasible scheme to prevent the data leakage of relational database.Based on the relational database,this paper summarizes the functional modules required by the relational database encryption system and proposes the overall framework of the cloud encryption database system.The SQL statements through this system need to rewrite with encrypting.The rewritten ciphertext statement is passed to the database for processing,which can ensure that the cloud database is securely stored and queried.According to the analysis of the theoretical scheme,the time cost based on ciphertext query should be no more than 1.2 times that of the plaintext data.2.The design scheme of rewriter is put forward in the cloud encryption database system,which not only enables transparent access to data users,but also need not modify the applications.The most important thing in the rewriter is the design and implementation of the lexical analysis and syntax analysis of the query.The lexical analysis provides the basis for the design of the syntax analysis.The syntax analysis provides the basis for the rewriting of the plaintext query statements into cipher text query statements.The implementation of complex query statements in encrypted database requires three functional modules of lexical analysis,syntax analysis,and custom grammar rules.3.The implementation of cloud encryption database system is experimented and tested on cloud computing platform.The experimental results show that the system can successfully complete the rewriting of the SQL query statement,and rewritten statements can be directly queried on the ciphertext,the query result executed on which is consistent with the plaintext,thus effectively guaranteeing the security of the data.The time cost should be no more than 1.2 times that of the plaintext data.