Structure Encryption Theory And Technology In Relational Database

Most of the past and present encryption methods of database system are data-value oriented. Such as the database encryption base on file, database encryption base on records, database encryption base on fields and other efficiency promoting and improving methods orient to data value etc. A new concept, theory, method and architecture of database structure encryption is proposed in this paper which is different from the usual data encryption but to the structure specialty of database system.Firstly, traditional database encryption methods are analyzed and studied, also summarized and classified. The limitation and defect of data value encryption'application in database system is pointed out. Therefore the meaning of database structure encryption is discussed.Secondly, the theory of database structure encryption is posed base on the structural character of data in database. Concept of semantic dependency is given by extending the concept of functional dependency that is one of the classical database formalization theory. The definitions of attributes incompatibility inside relational schema, relational schemas incompatibility inside database and records sequence incompatibility are stated. The rules of relational schemas'disassembling and recomposing are also proposed base on this. The security and efficiency of database structure encryption are evaluated.Thirdly, the mathematic model and theory of database structure encryption are described, the detail method, process and math modeling of database structure encryption are introduced. The architecture of database structure encryption is proposed. The problems exist in the method and the corresponding solutions for them are stated.Finally, a comprehensive security degree and efficiency analysis bycontrasting the database structure encryption and database data value encryption is finished through experiments. Eventually a prototype system is designed for database structure encryption.