Multistage Intrusion Tolerant Database Research

The research of database has two trends at present: The dependable database and intrusion tolerance database. The theoretical research of the dependable database concentrates on the multi-layer safe database , access controlling, database encoding , channel control and so on . The aim that the dependable database studies is to set up safer database. Intrusion tolerance database adopts existing COTS, for instance Oracle, DB2, SQL Server, SYBASE, etc., through redundancy and indirectly access, threshold, etc. and makes the system elastic, so it can guarantee the availability, integrity and confidentiality of the database in face of attacking. The aim of intrusion tolerance database is to utilize unauthentic DBMS to structure the believable database application system.This paper proceeds from the importance and demand of the database security, carries on the detailed and deep discussion in intrusion tolerance technology, and has fully expounded the characteristic and principle about the intrusion tolerance database. On this foundation, the p.aper proposes an orient-service database security model used by intrusion tolerance, and describes the components of the model in detail. This model adopts multilevel intrusion tolerance, combines the redundant technology with the diversified technology, and resists the attack about the operating system and database management system. So it can realize the availability and integrality about the database. With (t+1, n) Combinatorial Secret Sharing scheme, it can implement the confidentiality of the database. Using the transaction intrusion tolerance, it can take precaution against the transaction attack utilizing the legal user's information to carry on, especially can resist the inside attack effectively.The paper discusses in detail the principle that uses redundancy isomerous database servers and voting protocol to contain intrusion, and itpresents the design project of the voting protocol and the realization of the arithmetic. It also puts forward a kind of design project, which is realized by trigger ,to synchronize the data in redundant database. At the same time, an intrusion tolerance database system prototype is developed to verify possibility of the model. In order to guarantee the confidentiality of sensitive data, the paper presents a kind of saving project of sensitive data based (/+1, n) on Combinatorial Secret Sharing scheme. Even occupied the database server, the invader also can't obtain the secret data. Compared with (t, n) standard secret sharing scheme of Shamir, (/+1, n) Combinatorial Secret Sharing scheme only carry out some module add and module subtract, sharply reduce the expense of the calculate. So it can be realized simply, and has higher efficiency at the same time.Finally, the paper discusses the existing problems and the research directions about the intrusion tolerance database.The paper presents an intrusion tolerance database system model, which adopted service oriented, secret shares, indirectly interview, redundancy with variety etc. technique, therefore have the redundancy, safe etc. characteristics. The system is done not depend on safety of single parts. Even a certain module was offended to break , the whole system also can't be paralyzed by the invader. In addition, because of intrusion tolerance database is established on top of the COTS groupware, therefore it still has characteristics of low cost, expands easily, short Development period etc..