Due to the dynamic nature of WAHN communications and the multi-node involvement in most WAHN applications, group key management has been proposed for efficient support of secure communications in WAHNs. Exclusion Basis Systems (EBS) provide a framework for scalable and efficient group key management where the number of keys per node and the number of re-key messages can be relatively adjusted. EBS-based solutions, however, may suffer from collusion attacks, where a number of nodes may collaborate to reveal all system keys and consequently capture the network. In this paper we investigate the collusion problem in EBS and demonstrate that a careful assignment of keys to nodes reduces collusion. Since an optimal assignment is NP hard, we propose a location-based heuristic where keys are assigned to neighboring nodes depending on the hamming distance between the strings of bits representing the used subset of the keys employed in the system. Simulation results have demonstrated that our proposed solution significantly boosts the network resilience to potential collusion threats.

No abstract

No abstract

The problem of peer prediction is to elicit information from agents in settings without any objective ground truth against which to score reports. Peer prediction mechanisms seek to exploit correlations between signals to align incentives with truthful reports. A long-standing concern has been the possibility of uninformative equilibria. For binary signals, a multi-task mechanism [Dasgupta and Ghosh 2013] achieves strong truthfulness, so that the truthful equilibrium strictly maximizes payoff. We characterize conditions on the signal distribution for which this mechanism remains strongly-truthful with non-binary signals, also providing a greatly simplified proof. We introduce the Correlated Agreement (CA) mechanism, which handles multiple signals and provides informed truthfulness: no strategy profile provides more payoff in equilibrium than truthful reporting, and the truthful equilibrium is strictly better than any uninformed strategy (where an agent avoids the effort of obtaining a signal). The CA mechanism is maximally strongly truthful, in that no mechanism in a broad class of mechanisms is strongly truthful on a larger family of signal distributions. We also give a detail-free version of the mechanism that removes any knowledge requirements on the part of the designer, using reports on many tasks to learn statistics while retaining -informed truthfulness.

Abstract-Advances in semiconductor technology have resulted in the creation of miniature medical embedded systems that can wirelessly monitor the vital signs of patients. These lightweight medical systems can aid providers in large disasters who become overwhelmed with the large number of patients, limited resources, and insufficient information. In a mass casualty incident, small embedded medical systems facilitate patient care, resource allocation, and real-time communication in the Advanced Health and Disaster Aid Network (AID-N). We present the design of electronic triage tags on lightweight, embedded systems with limited memory and computational power. These electronic triage tags use noninvasive, biomedical sensors (pulse oximeter, electrocardiogram, and blood pressure cuff) to continuously monitor the vital signs of a patient and deliver pertinent information to first responders. This electronic triage system facilitates the seamless collection and dissemination of data from the incident site to key members of the distributed emergency response community. The real-time collection of data through a mesh network in a mass casualty drill was shown to approximately triple the number of times patients that were triaged compared with the traditional paper triage system.