Time synchronization in wireless sensor networks

Time synchronization is basic requirements for various applications in wireless sensor network, e.g., event detection, speed estimating, environment monitoring, data aggregation, target tracking, scheduling and sensor nodes cooperation. Time synchronization is also helpful to save energy in WSN because it provides the possibility to set nodes into the sleeping mode. In wireless sensor networks all of above applications need that all sensor nodes have a common time reference. However, most existing time synchronization protocols are likely to deteriorate or even be destroyed when the WSNs attack by malicious intruders. The recently developed maximum and minimum consensus based time synchronization protocol (MMTS) is a promising alternative as it does not depend on any reference node or network topology. But MMTS is vulnerable to message manipulation attacks. In this thesis, we focus on how to defend the MMTS protocol in wireless sensor networks under message manipulation attacks. We investigate the impact of message manipulation attacks over MMTS. Then, a Secured Maximum and Minimum Consensus based Time Synchronization (SMMTS) protocol is proposed to detect and invalidate message manipulation attacks

Attack-Tolerant Time-Synchronization in Wireless Sensor Networks

Abstract—Achieving secure time-synchronization in wireless sensor networks (WSNs) is a challenging, but very important problem that has not yet been addressed effectively. This pa-per proposes an Attack-tolerant Time-Synchronization Protocol (ATSP) in which sensor nodes cooperate to safeguard the time-synchronization service against malicious attacks. ATSP exploits the high temporal correlation existing among adjacent nodes in a WSN to achieve (1) adaptive management of the profile of each sensor’s normal behavior, (2) distributed, cooperative detection of falsified clock values advertised by attackers or compromised nodes, and (3) significant improvement of syn-chronization accuracy and stability by effectively compensating the clock drifts with the calibrated clock. To reduce the risk of losing time-synchronization due to attacks on the reference node, ATSP utilizes distributed, mutual synchronization and confines the impact of attacks to a local area (where attacks took place). Furthermore, by maintaining an accurate profile of sensors’ normal synchronization behaviors, ATSP detects various critical attacks while incurring only reasonable communication and computation overheads, making ATSP attack-tolerant and ideal for resource-constrained WSNs. I

MOBILE DATA COLLECTOR FOR SECURE TIME SYNCHRONIZATION IN CLUSTERED WIRELESS SENSOR NETWORK

Secure time synchronization is a key requirement for many sophisticated application running on these networks. Most of the existing secure time synchronization protocols incur high communication and storage costs and are subject to a few known security attacks. In wireless sensor network (WSN), lifetime of the network is determined by the amount of energy consumption by the nodes. To improve the lifetime of the network, nodes are organized into clusters, in which the cluster head (CH) collects and aggregates the data. A special node called mobile data collector (MDC) is used to collect the data from the CH and transfer it to the base station (BS) By using proposed method MDC authenticated to CH by computing shared secret keys on the fly. Once the MDC and CH are authenticated, all the sensor nodes in the cluster are synchronized, time synchronization reduce the communication and storage requirements of each CH. Security analysis of this proposed system shows that it is highly robust against different attacks namely compromised CH, reply attack, message manipulation attack as well as pulse delay attack

Secure Precise Clock Synchronization for Interconnected Body Area Networks

Secure time synchronization is a paramount service for wireless sensor networks (WSNs) constituted by multiple interconnected body area networks (BANs). We propose a novel approach to securely and efficiently synchronize nodes at BAN level and/or WSN level. Each BAN develops its own notion of time. To this effect, the nodes of a BAN synchronize with their BAN controller node. Moreover, controller nodes of different BANs cooperate to agree on a WSN global and/or to transfer UTC time. To reduce the number of exchanged synchronization messages, we use an environmental-aware time prediction algorithm. The performance analysis in this paper shows that our approach exhibits very advanced security, accuracy, precision, and low-energy trade-off. For comparable precision, our proposal outstands related clock synchronization protocols in energy efficiency and risk of attacks. These results are based on computations

Attack Resilient Pulse Based Synchronization

Synchronization of pulse-coupled oscillators (PCOs) has gained significant attention recently due to increased applications in sensor networks and wireless communications. However, most existing results are obtained in the absence of malicious attacks. Given the distributed and unattended nature of wireless sensor networks, it is imperative to enhance the resilience of pulse-based synchronization against malicious attacks. To achieve this goal, we first show that by using a carefully designed phase response function (PRF), pulse-based synchronization of PCOs can be guaranteed despite the presence of a stealthy Byzantine attacker, even when legitimate PCOs have different initial phases. Next, we propose a new pulse-based synchronization mechanism to improve the resilience of pulse-based synchronization to multiple stealthy Byzantine attackers. We rigorously characterize the condition for mounting stealthy Byzantine attacks under the proposed new pulse-based synchronization mechanism and prove analytically that synchronization of legitimate oscillators can be achieved even when their initial phases are unrestricted, i.e., randomly distributed in the entire oscillation period. Since most existing results on resilient pulse-based synchronization are obtained only for all-to-all networks, we also propose a new pulse-based synchronization mechanism to improve the resilience of pulse-based synchronization that is applicable under general connected topologies. Under the proposed synchronization mechanism, we prove that synchronization of general connected legitimate PCOs can be guaranteed in the presence of multiple stealthy Byzantine attackers, irrespective of whether the attackers collude with each other or not. The new mechanism can guarantee resilient synchronization even when the initial phases of legitimate oscillators are distributed in a half circle. Then, to relax the limitation of the stealthy attacker model and the constraint on the legitimate oscillators\u27 initial phase distribution, we improved our synchronization mechanism and proved that finite time synchronization of legitimate oscillators can be guaranteed in the presence of multiple Byzantine attackers who can emit attack pulses arbitrarily without any constraint except that practical bit rate constraint renders the number of pulses from an attacker to be finite. The improved mechanism can guarantee synchronization even when the initial phases of all legitimate oscillators are arbitrarily distributed in the entire oscillation period. The new attack resilient pulse-based synchronization approaches in this dissertation are in distinct difference from most existing attack-resilient synchronization algorithms (including the seminal paper from Lamport and Melliar-Smith [1]) which require a priori (almost) synchronization among all legitimate nodes. Numerical simulations are given to confirm the theoretical results

Droplet: A New Denial-of-Service Attack on Low Power Wireless Sensor Networks

In this paper we present a new kind of Denial-of-Service attack against the PHY layer of low power wireless sensor networks. Overcoming the very limited range of jamming-based attacks, this attack can penetrate deep into a target network with high power efficiency. We term this the Droplet attack, as it attains enormous disruption by dropping small, payload-less frame headers to its victim's radio receiver, depriving the latter of bandwidth and sleep time. We demonstrate the Droplet attack's high damage rate to full duty-cycle receivers, and further show that a high frequency version of Droplet can even force nodes running on very low duty-cycle MAC protocols to drop most of their packets

Vulnerability analysis of satellite-based synchronized smart grids monitoring systems

The large-scale deployment of wide-area monitoring systems could play a strategic role in supporting the evolution of traditional power systems toward smarter and self-healing grids. The correct operation of these synchronized monitoring systems requires a common and accurate timing reference usually provided by a satellite-based global positioning system. Although these satellites signals provide timing accuracy that easily exceeds the needs of the power industry, they are extremely vulnerable to radio frequency interference. Consequently, a comprehensive analysis aimed at identifying their potential vulnerabilities is of paramount importance for correct and safe wide-area monitoring system operation. Armed with such a vision, this article presents and discusses the results of an experimental analysis aimed at characterizing the vulnerability of global positioning system based wide-area monitoring systems to external interferences. The article outlines the potential strategies that could be adopted to protect global positioning system receivers from external cyber-attacks and proposes decentralized defense strategies based on self-organizing sensor networks aimed at assuring correct time synchronization in the presence of external attacks

Efficient time synchronized one-time password scheme to provide secure wake-up authentication on wireless sensor networks

In this paper we propose Time Synchronized One-Time-Password scheme to provide secure wake up authentication. The main constraint of wireless sensor networks is their limited power resource that prevents us from using radio transmission over the network to transfer the passwords. On the other hand computation power consumption is insignificant when compared to the costs associated with the power needed for transmitting the right set of keys. In addition to prevent adversaries from reading and following the timeline of the network, we propose to encrypt the tokens using symmetric encryption to prevent replay attacks.Comment: International Journal Of Advanced Smart Sensor Network Systems (IJASSN), Vol 3, No.1, January 2013 http://airccse.org/journal/ijassn/papers/3113ijassn01.pd

A Survey on Wireless Sensor Network Security

Wireless sensor networks (WSNs) have recently attracted a lot of interest in the research community due their wide range of applications. Due to distributed nature of these networks and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. This problem is more critical if the network is deployed for some mission-critical applications such as in a tactical battlefield. Random failure of nodes is also very likely in real-life deployment scenarios. Due to resource constraints in the sensor nodes, traditional security mechanisms with large overhead of computation and communication are infeasible in WSNs. Security in sensor networks is, therefore, a particularly challenging task. This paper discusses the current state of the art in security mechanisms for WSNs. Various types of attacks are discussed and their countermeasures presented. A brief discussion on the future direction of research in WSN security is also included.Comment: 24 pages, 4 figures, 2 table