Integrated modeling for wireless sensor networks reliability and security

This paper considers the reliability and security modeling of wireless sensor networks (WSN) in an integrated manner. WSN are usually designed with fault-tolerant and intrusion-tolerant capabilities, which enable the system to fulfill the reliability and security requirements, respectively. Our approach unifies the attributes of fault-tolerance and intrusion-tolerance through the development of a WSN three universe model (WSN-TUM). Our modeling technique differentiates two types of WSN failures: security failures due to the occurrence of malicious intrusions which are represented in a dynamic fault tree (DFT); and traditional failures due to the malfunctions of the system's constituent components which are represented in a combination of probabilistic graph model and DFT model. Two practical issues, modular imperfect coverage and dependent common-cause failures, are also considered and represented in a DFT through a proposed probabilistic functional dependency gate and a proposed common-cause failure gate modeled after the existing FDEP gate. The resulting solution technique is applicable to Markov analyses and combinatorial methods such as binary decision diagrams for the analysis of both reliability and security