Online optimization of security-sensitive real-time storage applications for NAND flash memory storage systems

With many advantages like low cost, faster and non-volatile, NAND flash memory has become a critical component in building security-critical real-time embedded devices. In this paper, we are interested in online optimization of security-sensitive storage applications, whose workloads are unpredictable but have explicit deterministic or probabilistic timing constraints and certain security constraints. Sensitive data must be stored before a specific deadline, otherwise it will lose its validity. To address these challenges, this paper presents a Feedback Vulnerability and Utilization Control (FVUC) mechanism. FVUC employs two proportional-integral controllers, the Utilization Controller and Vulnerability Controller, to build a big feedback loop that dynamically monitors the system run-time status as well as decides how many flash pages would be encrypted by a cryptography algorithm. Relied on the accurate model and design, FVUC can make a balance between the utilization and vulnerability, and achieve a better overall performance. The advantages of FVUC are verified by a series of simulation experiments under a broad range of system configurations and run-time uncertainties.