A secure dynamic copy protocol in real-time secure database systems

Concurrency control for real-time secure database systems must satisfy not only logical data consistency but also timing constraints and security requirements associated with transactions. These conflicting natures between timing constraints and security requirements are often resolved by maintaining several versions (or secondary copies) on the same data items. In this paper, we propose a new lock-based concurrency control protocol, Secure Dynamic Copy Protocol, ensuring both conflicting requirements. Our protocol aims for reducing the storage overhead of maintaining secondary copies and minimizing the processing overhead of update history. The main idea of our protocol is to keep a secondary copy only when it is needed to resolve the conflicting read/write operations in real time secure database systems. For doing this, a secondary copy is dynamically created and removed during a transaction's read/write operations. While comparing the existing real-time security protocol, we have also examined the performance characteristics of our protocol through simulation under different workloads. The results show that our protocol consumed less storage and decreased the deadline missing transactions.