Abstract The availability of the Web service has been exposed to several threats such as distributed denial‐of‐service attack, which is not an unfamiliar terminology anymore. Sustaining availability against various attacks becomes the critical issue for high‐profile Web sites. In this paper, we propose a novel architecture providing Web service among client, called client cloud Web service, by utilizing resources of clients to enhance the availability. Client cloud Web service can be easily integrated into the current Internet protocol suite by providing a transparent layer in the middle of Hypertext Transfer Protocol layer and Transmission Control Protocol/Internet Protocol layer. It is shown by simulations that the proposed architecture can efficiently reduce the traffic when both the size of Web items and the number of requests from clients increase. Copyright © 2012 John Wiley & Sons, Ltd.

The forthcoming internet of things - an intelligent collaboration of resource-limited devices such as wireless sensor nodes that are embedded in the daily lives of users - poses new challenges to security and end-user privacy. One of the most challenging problems is the thwarting of replica attacks. Once a sensor node is physically captured, it can be reprogrammed and replicated into a large number of replicas, which may maliciously occupy the network. Thus far, various schemes have been proposed to detect replicas; however, most of them require expensive hardware such as a global positioning system. In general, the ideal price for a sensor node is as low as one dollar, and thus, it is equipped with limited resources; hence, it is not practical to employ additional devices. In this paper, we propose a low-priced and efficient solution for replica detection in static wireless sensor networks. Although the proposed solution does not need any additional hardware, it exhibits similar or better performance, as compared to existing schemes. Through simulation experiments, we show that the proposed solution provides comparable performance in terms of the replica detection ratio and the time required to detect replicas. Furthermore, we show that the proposed solution saves more energy than existing schemes in most of our simulations.

The forthcoming Internet of Things – an intelligent collaboration of resource‐limited static/mobile devices that are embedded in the daily lives of users – poses new challenges to security and end‐user privacy. One of the most challenging problems is how to thwart replica attacks. Once a device is captured physically by an attacker or contaminated by malicious code, it can be reprogrammed and the secret information inside can be duplicated into a large number of replicas that maliciously occupy the network and collect users private information without authorisation. In this study, the authors focus on studying the detection of replicas in mobile applications; which can consist of resource‐limited static devices attached to mobile entities. Most existing solutions for detecting replicas have been designed for static devices, and cannot be immediately applied to mobile devices because of their unique properties, in particular, their node mobility. The authors present two efficient methods for detecting replicas in mobile devices. Through performance evaluations, they find that the proposed methods provide highly accurate replica detection with nearly zero detection errors. Furthermore, the distributed and cooperative strategy of the methods significantly reduces the energy required to detect replicas while providing faster replica detection than the existing solutions.