A Context-Dependent Trust Model for the MAC Layer in LR-WPANs

Abstract

Low rate wireless personal networks are vulnerable to several attacks focused on the Media Access Layer. Malicious or faulty nodes can subvert CSMA/CA and GTS allocation algorithms, achieving MAC unfairness in order to obtain higher medium access priority or to interrupt legitimate communication, ultimately leading to Denial-of-Service. While there exist secure protocol frameworks for LR-WPANs and diverse countermeasures against these attacks, most of them do not fit the usual computational and power supply constraints of LR- WPAN nodes, which require less computationally intensive methods such as trust models. We extend a bayesian trust model designed to detect such attacks by introducing context-dependent parameters and a flexible ageing factor which enable adaptive control of the proposed trust model based on specific context attributes and on changing network conditions.