Access Control To Hierarchical Encrypted Databases In The DAS Model

With the rapid advances in information system,Internet technologies and e-Bussiness. computer has been applied in all kinds of fields.At the same time,It is very important for the organizations to ensure the confidentiality and the integrality of the sensitive information.In order to satisfy the exigent requirement,utilizing the database service provider (DSP) can provide convenient and effective services to the owner of database,credible client and legitimate users.The DAS model is based on the third party providing service.Owners of the database store the sensitive information on the out of the control server.Illegal users can not access the sensitive information.The thesis first focus on how to combine the management of the session keys with the hierarchy access control.The user hierarchy partitions are base on the managing relation of the users.Then utilizing unsymmetrical encrypted algorithm encrypts the session keys.The keys of session keys are updated in a small field,when the managing relations change.Finally we design an interface frame between the client and the server.The interface frame is in order to conceive the decryption pair,when the owner of database add user,delete user and changing the relation among the users.