On secure connectivity with adjusting power to cope with jamming in sensor networks

In order to provide security services in wireless sensor networks, a well-known task is to provide cryptographic keys to sensor nodes prior to deployment. It is difficult to assign secret keys for all pairs of sensor node when the number of nodes is large due to the large numbers of keys required and limited memory resources of sensor nodes. One possible solution is to randomly assign a few keys to sensor nodes and have nodes be able to connect to each other with some probability. This scheme has limitations in terms of the tradeoffs between connectivity and memory requirements. Recently, sensor deployment knowledge has been used to improve the level of connectivity while using lesser amounts of memory space. However, deployment based key predistribution schemes may cause a large number of nodes to be cryptographically isolated if nodes move after key pre-distribution. Mobility may be necessitated for reasons depending on applications or scenarios. In this paper, we consider mobility due to spatial retreat of nodes under jamming attacks as an example. Jamming attacks are easy and efficient means for disruption of the connectivity of sensors and thus the operation of a sensor network. One solution for mobile sensor nodes to overcome the impact of jamming is to perform spatial retreats by moving nodes away from jammed regions. Moved nodes may not be able to reconnect to the network because they do not have any shared secret with new neighbors at new locations if strict deployment knowledge based key predistribution is employed. In this paper, we propose a hybrid key predistribution scheme that supports spatial retreat strategies to cope with jamming attacks. Our scheme combines the properties of random and deployment knowledge based key predistribution schemes. In the presence of jamming attacks, our scheme provides high key connectivity (similar to deployment knowledge based schemes) while reducing the number of isolated nodes. We evaluate the performance of our scheme through simulations and analysis.

Pairwise key establishment is a fundamental security service in sensor networks; it enables sensor nodes to communicate securely with each other using cryptographic techniques. However, due to the resource constraints on sensors, it is infeasible to use traditional key management techniques such as public key cryptography and key distribution center (KDC). To facilitate the study of novel pairwise key predistribution techniques, this paper presents a general framework for establishing pairwise keys between sensors on the basis of a polynomial-based key predistribution protocol [2]. This paper then presents two efficient instantiations of the general framework: a random subset assignment key predistribution scheme and a grid-based key predistribution scheme. The analysis in this paper indicates that these two schemes have a number of nice properties, including high probability (or guarantee) to establish pairwise keys, tolerance of node captures, and low communication overhead. Finally, this paper presents a technique to reduce the computation at sensors required by these schemes.

The establishment of shared keys between communicating neighbor nodes in wireless sensor networks is a challenge due to resource-constrained sensor networks. Several key pre-distribution schemes have been proposed in literatures to establish pairwise keys between sensor nodes. However, many of them are either too complicated to fit for wireless sensor networks or insecure for some common aggressions. In this paper, we propose a random key management scheme based on random key pre-distribution for wireless sensor networks. To achieve better performance and security, the proposed scheme employs two different phases to establish enhanced pairwise keys between neighboring nodes. Compared with other existing random key pre-distribution schemes, our scheme has better resilience against node capture and also performs better in terms of network connectivity and scalability with appropriate memory, computation and communication overheads.

Owing to the security requirements of wireless sensor network, the background of Wireless Sensor Network (WSN) is to be analyzed with different threats and attack models. Physical compromising of sensor nodes by an adversary is an emerging problem in sensor network and accordingly, it is necessary to provide an environment with efficient key management techniques due to resource constraints on sensor network. It is obvious to evaluate the efficiency of symmetric key management schemes for WSN, since it is not feasible to use traditional key management techniques such as asymmetric key cryptosystem and Key Distribution Center (KDC). This survey paper aims to report an extensive study on classification of pairwise key pre-distribution techniques. Further a smaller portion of analysis and security issues using pairwise key management is pronounced. Analysed results shows that polynomial pool based method have higher probability of communication by non-compromised nodes when compared with other schemes. The proposed survey effectively track the merits and demerits of different key predistribution schemes, also the communication overhead and memory overhead is reduced in polynomial pool based method during execution.

Security of wireless sensor networks is a major issue to protect sensor nodes from the attacker. Key management or key pre-distribution (KPS) is the preliminary step in the security of a sensor network, where secret keys are loaded into the sensor node’s memory before placement of the node in target positions. Various schemes for KPS have been proposed for location dependent as well as location independent wireless sensor networks. Costas arrays are $$n \times n$$ matrices grid represented where dots are placed for the l’s and leave blanks for the 0’s of the matrix for a positive integer n with the property that the vectors connecting two dots of the grid are all distinct as vectors. Costas arrays have a wide range of application including the construction of sonar signal pattern, cryptography, etc. Due to the Costas arrays property of uniqueness among their elements, it can be used in key pre-distribution of wireless sensor networks, especially in a location-dependent grid-based network. In this paper, we have proposed a Costas array based key pre-distribution scheme. Simulations are done on different network scenarios and the results were analyzed. Comparative performance analysis of the scheme is shown for different grid sized network considering various order of Costas array.

SCON: Secure management of continuity in sensor networks

To solve the security problem of wireless sensor networks, the concept of matrix pool and matrix grid were put forward, upon which our key pre-distribution scheme was built. And in the matrix grid based scheme, encryption was introduced into the process of key transfer. Using Blom's key pre-distribution for reference, an efficient key pre-distribution scheme was presented for sensor networks.

Any key pre-distribution (KPD) scheme is inherently a trade-off between complexity and security. By sacrificing some security (KPD schemes need some assurance of the ability to limit sizes of attacker coalitions), KPD schemes gain many advantages. We argue that random KPD schemes, in general, perform an advantageous trade-off which renders them more suitable for practical large scale deployments of resource constrained nodes. We introduce a novel random KPD scheme, hashed random preloaded subsets (HARPS), which turns out to be a generalization of two other random KPD schemes, random preloaded subsets (RPS) and a scheme proposed by T. Leighton and S. Micali (LM). All three schemes have probabilistic measures for the merit of the system. We analyze and compare the performance of the three schemes. We show that HARPS has significant advantages over other KPD schemes, and in particular, over RPS and LM.

In wireless sensor network (WSN), a secure link in the key pre-distribution (KP) scheme may be compromised when sensor nodes are captured. Accordingly, the KP q- composite scheme was proposed to tackle this node-capture problem. Recently, Bechkit et al. proposed a hash chain based KP (HCKP) q-composite scheme to further enhance network resiliency against node capture. However, Bechkit et al.'s HCKP q-composite scheme has to perform too many hash operations to establish a secure link between two nodes for the case that the difference of node identifiers is large. This computational overhead is more serious for the large value of q. In this paper, we propose a computational overhead invariant HCKP q-composite scheme by storing one additional hashed value in sensor node. When compared with Bechkit et al.'s HCKP q-composite scheme, the proposed scheme reduces the number of hash operations, and meanwhile the storage overhead remains insignificant.

Utilizing hash graphs for key distribution for mobile and replaceable interconnected sensors in the IoT context

Homogeneous wireless sensor networks (HWSNs) are a class of WSNs in which nodes have identical hardware configurations. A HWSN inherits the same constraints from WSNs such as limited processing capacity and resources. However, the unique characteristic of HWSNs gets more attention for recent security applications. The environment of these applications mandates lightweight security provisions, especially a key management protocol that endures security threats such as node capture attack. On the other hand, the limited computation and communication capabilities of sensor nodes make it hard to deal with such security threats. Thus, in this paper, we introduce a novel clustering paradigm to be used in a key pre-distribution key management scheme designed for HWSNs. Then, we develop a cluster-based key pre-distribution based on this paradigm. Our developed scheme improves the security dramatically by partitioning sensor nodes to the disjointed clusters and letting clusters to be inter-connected via randomly selected nodes as consular nodes from all the clusters to form a universal cluster. As opposed to the adopted schemes, we provide a comprehensive analysis for both sensor node connectivity, and resiliency against node capture attack, and also computational results are presented.

Key pre-distribution is an important area of research in Distributed Sensor Networks (DSN). Two sensor nodes are considered connected for secure communication if they share one or more common secret key(s). It is important to analyze the largest subset of nodes in a DSN where each node is connected to every other node in that subset (i.e., the largest clique). This parameter (largest clique size) is important in terms of resiliency and capability towards efficient distributed computing in a DSN. In this paper, we concentrate on the schemes where the key pre-distribution strategies are based on transversal design and study the largest clique sizes. We show that merging of blocks to construct a node provides larger clique sizes than considering a block itself as a node in a transversal design.

SummaryLow cost, decentralized architecture and ad hoc nature are a few desirable properties of wireless sensor networks that make them well suited for gathering sensitive information in hazardous deployment grounds. Existing security protocols exploit various cryptographic tools to strengthen their security. Not many works focus on constraints faced by an adversary. One such constraint being practical difficulties to trace a particular frequency band from a large range of unknown frequencies, specially in unharmonious geographical locations. Our research capitalizes on this weakness encountered by an adversary and preassigns nodes with multiple frequency bands from a wide range of frequencies allocated to the network. Deployed nodes can discover these bands during set network setup phase by a simple trick. Nodes are to internally switch their frequency bands depending on parametric variation that are caused by an (external) impulse. Experiments conducted using magneto optic sensors confirm that any variation of their parameter affects frequencies of emergent waves. Similar behavior is expected from application specific sensors. Frequency regulation (FR) concept is applied to combinatorial key predistribution schemes (KPS) having (regular) degree r. Depending on r and each node's capability to switch internal frequencies, nodes are preallocated with n frequency bands. This naturally partitions the (distributed) network and results in improved resilience. Combining our FR concept to a KPS where the number of shared key between a pair of nodes is at most one (γ ≤ 1) may yield best case scenario of an ideally resilient key predistribution. Our analysis of systems that combines FR idea with KPS where γ > 1 leads to an optimized key‐band distribution argument and drastic resilience improvements. Results of simulations conducted assuming real‐life scenario ascertain our analysis and establishes superior performance of our protocols as compared to prominent ones.

Preferential attachment models have been widely studied in complex networks, because they can explain the formation of many networks like social networks, citation networks, power grids, and biological networks, to name a few. Motivated by the application of key predistribution in wireless sensor networks (WSN), we initiate the study of preferential attachment with degree bound. Our paper has two important contributions to two different areas. The first is a contribution in the study of complex networks. We propose preferential attachment model with degree bound for the first time. In the normal preferential attachment model, the degree distribution follows a power law, with many nodes of low degree and a few nodes of high degree. In our scheme, the nodes can have a maximum degree $d_{\max}$, where $d_{\max}$ is an integer chosen according to the application. The second is in the security of wireless sensor networks. We propose a new key predistribution scheme based on the above model. The important features of this model are that the network is fully connected, it has fewer keys, has larger size of the giant component and lower average path length compared with traditional key predistribution schemes and comparable resilience to random node attacks. We argue that in many networks like key predistribution and Internet of Things, having nodes of very high degree will be a bottle-neck in communication. Thus, studying preferential attachment model with degree bound will open up new directions in the study of complex networks, and will have many applications in real world scenarios.

A novel key predistribution scheme for wireless sensor networks based on hexagon deployment model