In order to reduce car accidents, provide emergency information, novel applications on vehicular ad hoc networks (VANETs) have drawn a lot of attention in resent years. This paper presents a new security threat on VANET applications called illusion attack. In this attack, based on the current during condition on the road, the adversary broadcasts the scene-aligned traffic warning messages, which produce an illusion to cars at its neighborhood. In consequence, the illusion can largely manipulate other drivers' behaviors on their responses. The illusion attack can easily cause car accident, traffic jam and the decrease of VANET performance in terms of bandwidth utilization. We discuss the reasons why traditional authentication mechanisms cannot resolve this security threat effectively and propose a new model, called plausibility validation network (PVN), to remedy the illusion attack. Finally, we analyze the security properties and potential overhead of proposed model.

Modern societies are moving toward an information-oriented environment. To gather and utilize information around people’s modern life, tiny devices with all kinds of sensing devices and various sizes of gateways need to be deployed and connected with each other through the Internet or proxy-based wireless sensor networks (WSNs). Within this kind of Internet of Things (IoT) environment, how to authenticate each other between two communicating devices is a fundamental security issue. As a lot of IoT devices are powered by batteries and they need to transmit sensed data periodically, it is necessary for IoT devices to adopt a lightweight authentication protocol to reduce their energy consumption when a device wants to authenticate and transmit data to its targeted peer. In this paper, a lightweight continuous authentication protocol for sensing devices and gateway devices in general IoT environments is introduced. The concept of valid authentication time period is proposed to enhance robustness of authentication between IoT devices. To construct the proposed lightweight continuous authentication protocol, token technique and dynamic features of IoT devices are adopted in order to reach the design goals: the reduction of time consumption for consecutive authentications and energy saving for authenticating devices through by reducing the computation complexity during session establishment of continuous authentication. Security analysis is conducted to evaluate security strength of the proposed protocol. In addition, performance analysis has shown the proposed protocol is a strong competitor among existing protocols for device-to-device authentication in IoT environments.