Security Policy for Covert Channel Problem of Real-Time Databases
针对实时数据库中隐蔽通道问题采取的安全策略

The decisive objective of real-time database is to maximize the number of the transactions that complete be- fore their deadlines, then management and transaction processing for real-time systems are essential in supporting time-critical applications. However, as real-time systems continue to evolve, security is another problem that must be considered in many real-time application. So security becomes another problem that must be considered. This paper discusses security problem according to covert channel, extends conurrency control algorithm in real-time database systems to satisfy both timing constraint and security constraint by defining CCF and DCCF variables. Demonstrating non-interference which can avoid covert channel and studying the feasibility of tdrieliness and security requirement maintained at the same time.