无线传感器网络的轻量级安全体系研究

结合无线传感器网络现有的安全方案存在密钥管理和安全认证效率低等问题的特点,提出了无线传感器网络的轻量级安全体系和安全算法。采用门限秘密共享机制的思想解决了无线传感器网络组网中遭遇恶意节点的问题;采用轻量化ECC算法改造传统ECC算法,优化基于ECC的CPK体制的思想,在无需第三方认证中心CA的参与下,可减少认证过程中的计算开销和通信开销,密钥管理适应无线传感器网络的资源受限和传输能耗相当于计算能耗千倍等特点,安全性依赖于椭圆离散对数的指数级分解计算复杂度;并采用双向认证的方式改造,保证普通节点与簇头节点间的通信安全,抵御中间人攻击。     

WSNs中基于秘密共享的身份认证协议

身份认证是无线传感器网络安全的第一道屏障。针对现有无线传感器网络中的身份认证协议的效率和安全问题,基于Shamir门限秘密共享方案提出一种低功耗的身份认证协议。在不降低网络安全性的前提下,通过多个已认证节点对新节点进行身份认证,能够有效的降低认证过程中的计算量。认证过程中使用单向散列函数对通信数据进行加密并且运用时间戳机制抵御重放攻击。分析结果表明协议具有低功耗的特点,并且能够抵御窃听攻击、重放攻击以及少数节点被俘虏的攻击。     

A Simple Algorithm for Data Compression in Wireless Sensor Networks

Power saving is a critical issue in wireless sensor networks (WSNs) since sensor nodes are powered by batteries which cannot be generally changed or recharged. As radio communication is often the main cause of energy consumption, extension of sensor node lifetime is generally achieved by reducing transmissions/receptions of data, for instance through data compression. Exploiting the natural correlation that exists in data typically collected by WSNs and the principles of entropy compression, in this Letter we propose a simple and efficient data compression algorithm particularly suited to be used on available commercial nodes of a WSN, where energy, memory and computational resources are very limited. Some experimental results and comparisons with, to the best of our knowledge, the only lossless compression algorithm previously proposed in the literature to be embedded in sensor nodes and with two well- known compression algorithms are shown and discussed.     

Self-Recommendation Mechanism in Trust Calculation Among Nodes in WSN

This paper proposes a node self-recommendation mechanism which is effective in trust calculation model in wireless sensor networks (WSNs). The mechanism has little practical sense to cable and wireless network among which nodes’ resources, especially energy, are almost unlimited; furthermore it may bring some security risk to networks on the contrary. But as to WSNs where nodes’ resources are strictly limited, a node can express its intension of participating communication to its neighbors by using the mechanism according to its current running state and predefined strategies. This mechanism is useful to save nodes’ energy, balance network load and prolong network lifetime ultimately. The paper focuses on self-recommendation value expression, calculation and synthesis method. Application method of the mechanism is also discussed. Simulation results show that using trust calculation model cooperatively with self-recommendation mechanism can protect low energy nodes effectively and balance energy consumption among adjacent nodes without weakening malicious node identification function of the trust model.

     

An improved key distribution mechanism for large-scale hierarchical wireless sensor networks

Wireless sensor networks are often deployed in hostile environments and operated on an unattended mode. In order to protect the sensitive data and the sensor readings, secret keys should be used to encrypt the exchanged messages between communicating nodes. Due to their expensive energy consumption and hardware requirements, asymmetric key based cryptographies are not suitable for resource-constrained wireless sensors. Several symmetric-key pre-distribution protocols have been investigated recently to establish secure links between sensor nodes, but most of them are not scalable due to their linearly increased communication and key storage overheads. Furthermore, existing protocols cannot provide sufficient security when the number of compromised nodes exceeds a critical value. To address these limitations, we propose an improved key distribution mechanism for large-scale wireless sensor networks. Based on a hierarchical network model and bivariate polynomial-key generation mechanism, our scheme guarantees that two communicating parties can establish a unique pairwise key between them. Compared with existing protocols, our scheme can provide sufficient security no matter how many sensors are compromised. Fixed key storage overhead, full network connectivity, and low communication overhead can also be achieved by the proposed scheme.     

Improving wireless sensor networks performance through epidemic model

Wireless sensor networks (WSNs) encounter a critical challenge of ‘Network Security’ due to extreme operational constraints. The origin of the challenge begins with the entry of worms in the wireless network. Just one infected node is enough to spread the worms across the entire network. The infected node rapidly infects the neighbouring nodes in an unstoppable manner. In this paper, a mathematical model is proposed based on epidemic theory. It is an improvement of the Susceptible-Infectious-Recovered-Susceptible (SIRS) and Susceptible-Exposed-Infectious-Susceptible (SEIS) model. We propose Susceptible-Exposed-Infectious-Recovered-Susceptible (SEIRS) model that overcomes the drawbacks of existing models. The proposed ameliorated model includes a finite communication radius and the associated node density. We obtain basic reproduction number which determines the local and global propagation dynamics of worm in the WSNs. Also, we deduce expression for threshold for node density and communication radius. We investigated the control mechanism against worm propagation. We compare the proposed model with various existing models and evaluate its performance on the basis of various performance metrics. The study confirms melioration in the vital aspects (security, network reliability, transmission efficiency, energy efficiency) for WSNs. The proposed SEIRS model provides an improved technique to restraint worms’ transmission in comparison to the existing models.     

An Efficient Grid-Based Pairwise Key Predistribution Scheme for Wireless Sensor Networks

Research on wireless sensor networks (WSNs) has been receiving a lot of attention recently. Because of the constraints on the cost of hardware, there are a lot of restrictions regarding memory, computational ability, and energy consumption, hampering WSN research. So far, many key establishment schemes have been proposed for WSNs. For the proposed schemes, random key predistribution is a practical solution. With this, each sensor shares a common key with its neighbors via predistributed keys. However, it may happen that two sensor nodes do not share a common key. In this paper, an efficient grid-based pairwise key predistribution scheme for WSNs is proposed. In the proposed scheme, multiple polynomials for each row, each column, and each diagonal in the grid are constructed. Then, each sensor node in each row, column, and diagonal in the grid establishes a pairwise key with the other node using the predistributed symmetric polynomial. Simulation results demonstrate the effectiveness of the proposed scheme in increasing the probability of establishing pairwise keys and reducing communication overhead.     

DUCR: Distributed unequal cluster‐based routing algorithm for heterogeneous wireless sensor networks

Designing energy efficient communication protocols for wireless sensor networks (WSNs) to conserve the sensors' energy is one of the prime concerns. Clustering in WSNs significantly reduces the energy consumption in which the nodes are organized in clusters, each having a cluster head (CH). The CHs collect data from their cluster members and transmit it to the base station via a single or multihop communication. The main issue in such mechanism is how to associate the nodes to CHs and how to route the data of CHs so that the overall load on CHs are balanced. Since the sensor nodes operate autonomously, the methods designed for WSNs should be of distributed nature, i.e., each node should run it using its local information only. Considering these issues, we propose a distributed multiobjective‐based clustering method to assign a sensor node to appropriate CH so that the load is balanced. We also propose an energy‐efficient routing algorithm to balance the relay load among the CHs. In case any CH dies, we propose a recovery strategy for its cluster members. All our proposed methods are completely distributed in nature. Simulation results demonstrate the efficiency of the proposed algorithm in terms of energy consumption and hence prolonging the network lifetime. We compare the performance of the proposed algorithm with some existing algorithms in terms of number of alive nodes, network lifetime, energy efficiency, and energy population.     

A selective encryption and energy efficient clustering scheme for video streaming in wireless sensor networks

The past few years have witnessed increased interest in the potential use of wireless sensor networks (WSNs) in applications such as battlefield assistance, adversary intrusion detection, distributed signal processing, etc. In these applications, multimedia semantic information and video content are extremely sensitive to malicious attacks, including eavesdropping/intercepting of ongoing traffic, and manipulating/counterfeiting of the existing media flows. From a security standpoint, it is very important to transmit authentic and accurate data to surrounding sensor nodes and to the sink. However, securing sensor networks poses unique challenges because these tiny wireless devices are deployed in large numbers, usually in unattended environments, and are severely limited in their capabilities and resources like power, computational capacity, and memory. In this work, a secure and selective encryption framework is proposed so as to optimize network lifetime and video distortion for an energy constrained wireless video sensor network (WVSN).     

LEDS: Providing Location-Aware End-to-End Data Security in Wireless Sensor Networks

Providing desirable data security, that is, confidentiality, authenticity, and availability, in wireless sensor networks (WSNs) is challenging, as a WSN usually consists of a large number of resource constraint sensor nodes that are generally deployed in unattended/hostile environments and, hence, are exposed to many types of severe insider attacks due to node compromise. Existing security designs mostly provide a hop-by-hop security paradigm and thus are vulnerable to such attacks. Furthermore, existing security designs are also vulnerable to many types of denial of service (DoS) attacks, such as report disruption attacks and selective forwarding attacks and thus put data availability at stake. In this paper, we seek to overcome these vulnerabilities for large-scale static WSNs. We come up with a location-aware end-to-end security framework in which secret keys are bound to geographic locations and each node stores a few keys based on its own location. This location-aware property effectively limits the impact of compromised nodes only to their vicinity without affecting end-to-end data security. The proposed multifunctional key management framework assures both node-to-sink and node-to-node authentication along the report forwarding routes. Moreover, the proposed data delivery approach guarantees efficient en-route bogus data filtering and is highly robust against DoS attacks. The evaluation demonstrates that the proposed design is highly resilient against an increasing number of compromised nodes and effective in energy savings.     

A Secure Key Predistribution Scheme for WSN Using Elliptic Curve Cryptography

Security in wireless sensor networks (WSNs) is an upcoming research field which is quite different from traditional network security mechanisms. Many applications are dependent on the secure operation of a WSN, and have serious effects if the network is disrupted. Therefore, it is necessary to protect communication between sensor nodes. Key management plays an essential role in achieving security in WSNs. To achieve security, various key predistribution schemes have been proposed in the literature. A secure key management technique in WSN is a real challenging task. In this paper, a novel approach to the above problem by making use of elliptic curve cryptography (ECC) is presented. In the proposed scheme, a seed key, which is a distinct point in an elliptic curve, is assigned to each sensor node prior to its deployment. The private key ring for each sensor node is generated using the point doubling mathematical operation over the seed key. When two nodes share a common private key, then a link is established between these two nodes. By suitably choosing the value of the prime field and key ring size, the probability of two nodes sharing the same private key could be increased. The performance is evaluated in terms of connectivity and resilience against node capture. The results show that the performance is better for the proposed scheme with ECC compared to the other basic schemes.     

A Robust Mutual Authentication Protocol for Wireless Sensor Networks

Authentication is an important service in wireless sensor networks (WSNs) for an unattended environment. Recently, Das proposed a hash‐based authentication protocol for WSNs, which provides more security against the masquerade, stolen‐verifier, replay, and guessing attacks and avoids the threat which comes with having many logged‐in users with the same login‐id. In this paper, we point out one security weakness of Das' protocol in mutual authentication for WSN's preservation between users, gateway‐node, and sensor nodes. To remedy the problem, this paper provides a secrecy improvement over Das' protocol to ensure that a legal user can exercise a WSN in an insecure environment. Furthermore, by presenting the comparisons of security, computation and communication costs, and performances with the related protocols, the proposed protocol is shown to be suitable for higher security WSNs.     

Energy adaptive MAC for wireless sensor networks with RF energy transfer: algorithm,analysis, and implementation

Radio frequency energy transfer (RET) has been proposed as a promising solution to power sensor nodes in wireless sensor networks (WSNs). However, RET has a significant drawback to be directly applied to WSNs, i.e., unfairness in the achieved throughput among sensor nodes due to the difference of their energy harvesting rates that strongly depend on the distance between the energy emitting node and the energy harvesting nodes. The unfairness problem should be properly taken into account to mitigate the drawback caused from the features of RET. To resolve this issue, in this paper, we propose a medium access control (MAC) protocol for WSNs based on RET with two distinguishing features: energy adaptive (EA) duty cycle management that adaptively manages the duty cycle of sensor nodes according to their energy harvesting rates and EA contention algorithm that adaptively manages contentions among sensor nodes considering fairness. Through analysis and simulation, we show that our MAC protocol works well under the RET environment. Finally, to show the feasibility of WSNs with RET, we test our MAC protocol with a prototype system in a real environment.     

Throughput Evaluation of a Novel Scheme to Mitigate the Congestion over WSNs

In recent years, due to fast development of wireless sensor networks (WSNs), the numbers of nodes are increasing, and their scope of applications is continuously expanding, including environmental monitoring, military and smart home applications. The power supply, memory and computing power of wireless sensor nodes are greatly hampered in WSNs so that the WSNs are classified as a task-oriented framework. This study focused on exploring problems caused by traffic congestion on the WSNs with a large amount of flow, such as packet loss, bandwidth reduction, and waste of energy on the sensor nodes. On the other hand, a cooperative strong node mechanism is presented and named as Cooperative Strong Node Mechanism, in which a threshold is set to determine whether the node traffic is over or not. When the load exceeds, the privilege of corresponding sensor nodes is upgraded so that it can command its child nodes to change the transmission path to distribute the traffic effectively. Furthermore, when the traffic exceeds preset overall network flow, new sensor nodes are added in the network to relieve the traffic. This novel proposed mechanism can not only increase network throughput and effectively prevent the occurrence from congestion problems, but is suitable for a variety of routing protocols.     

Tree‐based channel assignment schemes for multi‐channel wireless sensor networks

Many sensor node platforms used for establishing wireless sensor networks (WSNs) can support multiple radio channels for wireless communication. Therefore, rather than using a single radio channel for whole network, multiple channels can be utilized in a sensor network simultaneously to decrease overall network interference, which may help increase the aggregate network throughput and decrease packet collisions and delays. This method, however, requires appropriate schemes to be used for assigning channels to nodes for multi‐channel communication in the network. Because data generated by sensor nodes are usually delivered to the sink node using routing trees, a tree‐based channel assignment scheme is a natural approach for assigning channels in a WSN. We present two fast tree‐based channel assignment schemes (called bottom up channel assignment and neighbor count‐based channel assignment) for multi‐channel WSNs. We also propose a new interference metric that is used by our algorithms in making decisions. We validated and evaluated our proposed schemes via extensive simulation experiments. Our simulation results show that our algorithms can decrease interference in a network, thereby increasing performance, and that our algorithms are good alternatives for static channel assignment in WSNs. Copyright © 2015 John Wiley & Sons, Ltd.     

Balance energy-efficient and real-time with reliable communication protocol for wireless sensor network

In many wireless sensor network applications, it should be considered that how to trade off the inherent conflict between energy efficient communication and desired quality of service such as real-time and reliability of transportation. In this paper, a novel routing protocols named balance energy-efficient and real-time with reliable communication (BERR) for wireless sensor networks (WSNs) are proposed, which considers the joint performances of real-time, energy efficiency and reliability. In BERR, a node, which is preparing to transmit data packets to sink node, estimates the energy cost, hop count value to sink node and reliability using local information gained from neighbor nodes. BERR considers not only each sender’ energy level but also that of its neighbor nodes, so that the better energy conditions a node has, the more probability it will be to be chosen as the next relay node. To enhance real-time delivery, it will choose the node with smaller hop count value to sink node as the possible relay candidate. To improve reliability, it adopts retransmission mechanism. Simulation results show that BERR has better performances in term of energy consumption, network lifetime, reliability and small transmitting delay.     

Adaptive Load-Aware Congestion Control Protocol for Wireless Sensor Networks

Congestion control in wireless sensor networks (WSNs) is crucial. In this article, we discuss congestion control and the adaptive load-aware problem for sensor nodes in WSNs. When the traffic load of a specific node exceeds its the available capacity of the node, a congestion problem occurs because of buffer memory overflow. Congestion may cause serious problems such as packet loss, the consumption of power, and low network throughput for sensor nodes. To address these problems, we propose a distributed congestion control protocol called adaptive load-aware congestion control protocol (ALACCP). The protocol can adaptively allocate the appropriate forwarding rate for jammed sensor nodes to mitigate the congestion load. Through the buffer management mechanism, the congestion index of neighboring sensor nodes, and an adjustment of the adaptive forwarding rate, the degree of congestion is alleviated markedly. The performance in allocating the forwarding rate effectively to neighboring sensor nodes also improves. The ALACCP can avoid packet loss because of traffic congestion, reduce the power consumption of nodes, and improve the network throughput. Simulation results revealed that the proposed ALACCP can effectively improve network performance and maintain the fairness of networks.     

Priority-based IEEE 802.15.4 CSMA/CA mechanism for WSNs

The IEEE 802.15.4 standard is widely used in wireless sensor networks (WSNs). In this paper, we propose a priority-based IEEE 802.15.4 carrier sense multiple access with collision avoidance (CSMA/CA) mechanism for WSNs. Considering traffic load and traffic type of sensor nodes, we classify sensor nodes into three types. In our mechanism, different contention parameters are set for nodes with different priority levels, in order that nodes with high priority achieve high probability to access the channel. By modeling the proposed mechanism using a Markov chain, we analyze and compute the successful transmission probability, throughput and energy consumption for nodes with different priority levels. Finally, our numerical results demonstrate that our mechanism performs well for WSNs.     

Connectivity Analysis for Wireless Sensor Networks with Antenna Array Integrated Central Node

In a wireless sensor network (WSN), after gathering information, tiny sensor nodes need to transmit data to a sink. It is important to guarantee that each node can communicate with a sink. Due to the multi-hop communication of WSNs, an essential condition for reliable transmission is completely connectivity of a network. Adaptive or smart antenna (SA) techniques in WSNs have been a topic of active research in recent years. These techniques have been shown to be effective with respect to decreasing energy consuming via specified regions which are formed by the SA beams. In this paper, we propose a probabilistic technique to determine the network connectivity probability of the SA integrated WSN. We employ the geometric shape model to evaluate the network connectivity probability of the WSN using the SA beam specifications. The sensor node density to satisfy the desired network connectivity is determined in terms of the beam-width of the antenna array and node transmission range. The analytical results agree with the simulation results by less than 4.7 % error in the average.     

Energy Efficient Four Level Cooperative Opportunistic Communication for Wireless Personal Area Networks (WPAN)

For wireless sensor networks (WSNs), energy is a scarce resource. Due to limited battery resources, the energy consumption is the critical issue for the transmission as well as reception of the signals in the wireless communication. WSNs are infrastructure-less shared network demanding more energy consumption due to collaborative transmissions. This paper proposes a new cooperative opportunistic four level model for IEEE 802.15.4 wireless personal area network. The average per node energy consumption is observed merely about 0.17 mJ for the cooperative wireless communication which proves the proposed mechanism to be energy efficient. This paper further proposes four levels of cooperative data transmission from source to destination to improve network coverage with energy efficiency.