Imran Ali Jokhio

Node capture attack detection and defence in wireless sensor networks

Wireless sensor network (WSN) applications are often deployed under hostile environments. Monitoring sensor nodes carefully, detecting and providing defence against malicious activity in the region is a challenging task. Legitimate sensor nodes may be captured by an adversary to extract important security information regarding shared secrets and cryptographic keys. This type of attack may result in a severe WSN security breach. Using ‘tamper-resistant’ nodes for securing communication in a WSN cannot be considered as a solution against these attacks as it increases the network cost tremendously. Nevertheless, destroying a legitimate node by erasing its memory and destroying its radio service based on a misjudgement may bring severe damage to the WSN. The authors propose the novel sensor node capture attack detection and defence (SCADD) protocol. SCADD provides a cost-effective solution against the node compromise and capture attacks in WSNs, enhancing the overall WSN security for security-sensitive applications. This protocol consists of two building blocks: node attack detection block and defence advocating measure block. The former provides strategic-based attack detection to eliminate the possibility of misjudgement and the latter uses a self-destruction defence measure against node capture attack, without actually destroying the nodes radio service, to avoid a major security breach.

Light-weight framework for security-sensitive wireless sensor networks applications

For certain security-sensitive wireless sensor network (WSN) applications, physical location information of the sensor nodes must not be disclosed to any unauthorised entity. During the localisation phase for such applications the physical locations of sensor nodes are kept secret. Globally, a number of secure location estimation schemes have been proposed from various perspectives, but some important constraints of sensor nodes are often ignored. The considered limitations during design of those schemes vary with respect to varying research perspective. In this study, we propose a novel security framework for secure location estimation of sensor nodes suitable for security-sensitive WSN applications. The proposed framework aims to provide security, scalability, adaptability and optimise power consumption during the secure location estimation phase of a wireless sensor network. The designed framework consists of a two-way authentication scheme, a light-weight encryption mechanism and a novel secure key generation algorithm. The study discusses strengths of the components if used for secure localisation individually, as well as when used together as interactive parts of a security framework for WSN applications.

Delta-MFCC Features and Information Theoretic Expectation Maximization based Text-independent Speaker Verification System

Gaussian Mixture Model (GMM)-based speaker models yield very good performance in text.independent speaker verification systems. GMMs use expectation maximization (EM) as an optimization procedure to train speaker models. This paper proposes the information theoretic expectation maximization (ITEM) with improved convergence rates to train the speaker models. The approach amounts to information theoretic (IT) since it uses the parzen density estimation and Kullback.Leibler (KL) divergence measure. EM encounters the problem of convergence thus to enhance the convergence rates of EM, an IT procedure is incorporated. The proposed ITEM algorithm adapts means, covariances, and weights, like the conventional EM algorithm; however, this process is not conducted directly on feature vectors but on a smaller set of centroids derived by the IT procedure, which simultaneously minimizes the divergence between the Parzen estimates of the feature vectors distribution within a given class and the centroids distribution within the same class. The ITEM algorithm was applied to the speaker verification problem using NIST 2001, 2002, 2004, and 2006 speaker recognition evaluation corpora and MFCC with delta, energy, and zero-crossing features. The results showed an improvement of the equal error rate over the classical EM approach. The ITEM method also showed higher convergence rates compare with the EM method.Abstract With the application of compressed sensing theory, Nyquist folding receiver achieves a full-band reconnaissance with a low sampling rate. Based on this structure, we introduce the synchronization mechanism and take the form of binary phase shift keying signals as the digital local oscillator. The synchronization information is used to estimate the parameter of frequency agile signals through zoned conjugate matching. Simulations show that the probability of correct estimation of Nyquist zone is higher than 90% when signal to noise ratio is equal to or greater than −9 dB.

Wireless sensor network based flood/drought forecasting system

Early warnings with respect to natural disasters, specially floods and drought predictions play a vital role in saving precious lives and assets. Most of the population of Pakistan gets affected by the floods/drought every year. A huge loss associated with the natural disaster includes finance, asset and precious lives. In this paper we present a novel wireless sensor network (WSN) based flood/drought forecasting system (FDFS) for Pakistan to help authorities gain early information regarding flooding/drought possibilities and take timely measures for the relief. The proposed system has been simulated and tested using Network Simulator (NS).

Modelling and symmetry reduction of a target-tracking protocol using wireless sensor networks

To achieve precise modelling of real-time systems stochastic behaviours are considered which lead towards probabilistic modelling. Probabilistic modelling has been successfully employed in wide array of application domains including, for example, randomised distributed algorithms, communication, security and power management protocols. This study is an improvement over our previous work, which was based on the probabilistic analysis of a cluster-based fault tolerant target-tracking protocol (FTTT) using only grid-based sensor nodes arrangement. Probabilistic modelling is chosen for the analysis of FTTT protocol to facilitate benefits of symmetry reduction in conjunction with modelling. It is believed that for the first time correctness of the simplified version of a target-tracking protocol is verified by developing its continuous-time Markov chain (CTMC) model using symbolic modelling language. The proposed probabilistic model of a target-tracking wireless sensor networks will help to analyse the phases of FTTT protocol on a limited scale with finite utilisation of time. There are three main contributions of this study; first consideration of synchronised events between the modules, second, random placement of sensor nodes is taken into account in addition to grid-based sensor node arrangement, third one is the reduction in state space size through symmetry reduction technique, which also facilitates to analyse a larger size network. Symmetry reduction on Probabilistic Symbolic Model (PRISM) checker models is performed by PRISM-symm and the generic representatives in PRISM (GRIP) tool. Modelling of FTTT protocol is proved better with the usage of PRISM-symm after comparing the results of PRISM model, PRISM-symm and GRIP.

Intrusion damage assessment for multi-stage attacks for clouds

Clouds represent a major paradigm shift from contemporary systems, inspiring the contemporary approach to computing. They present fascinating opportunities to address dynamic user requirements with the provision of flexible computing infrastructures that are available on demand. Clouds, however, introducing novel challenges particularly with respect to security that require dedicated efforts to address them. This study is focused at one such challenge, that is, determining the extent of damage caused by an intrusion for a victim virtual machine. It has significant implications especially with respect to effective response to the intrusion. This study presents the efforts to address this challenge for Clouds in the form of a novel scheme for intrusion damage assessment for Clouds. In addition to its context-aware operation, the scheme facilitates protection against multi-stage attacks. The study also includes the formal specification and evaluation of the scheme, which successfully demonstrate its effectiveness to achieve rigorous damage assessment for Clouds.

Aggregating Node Level Risk Assessment in Grids Using an R-out-of-N Model

Risk assessment in Grids aims to improve the confidence level between the Resource Provider and End User to agree to a Service Level Agreement [SLA]. Risk assessment in Grids complements SLAs, which provide some improvement over the best effort approach. The existing efforts in risk assessment in Grids are at the granularity level of nodes or machines. We introduce Risk assessment aggregation at the node level based on R-out-of -N model. The experimental results show that R-out-of –N model provides more detailed options regarding the Risk value for selected R nodes against a total of N nodes.

Data Privacy Management in a Multi-Organizational RFID Authentication

The growing popularity of Radio Frequency Identification (RFID) systems cannot be overlooked due to their wide range of application areas. However, some RFID applications face security and privacy threats due to the exposure of tags over wider distances. There are security methods but these can lack security and scalability when authenticating RF tags in multi-organizational RFID system. RFID systems operating within a single domain have only security and privacy issues due to the security method on tags, but in a multi-organizational system there are even more security and privacy issues in the system architecture rather than just in the security method on tag side. In this paper, we have designed a broker service to EPC Network for secure and confidential data management of the RFID data events. Secure and confidential authentication broker service is an extension to the EPC network architecture for a multi-organizational RFID system. The central authentication broker service ensures to avoid any illicit access to the confidential RFID tags data such as EPC code, whilst managing a large-scale authentication data to ensure secure and deterministic response to the authentic entities of the system.

Intrusion Damage Assessment for Multi-stage Attacks for Clouds

Clouds represent a major paradigm shift from contemporary systems, inspiring the contemporary approach to computing. They present fascinating opportunities to address dynamic user requirements with the provision of flexible computing infrastructures that are available on demand. Clouds, however, introduce novel challenges particularly with respect to security that require dedicated efforts to address them. This paper is focused at one such challenge i.e. determining the extent of damage caused by an intrusion for a victim virtual machine. It has significant implications with respect to effective response to the intrusion. The paper presents our efforts to address this challenge for Clouds in the form of a novel scheme for intrusion damage assessment for Clouds which facilitates protection against multi-stage attacks. The paper also includes the formal specification and evaluation of the scheme which successfully demonstrate its effectiveness to achieve rigorous damage assessment for Clouds.

An authentication broker service for secure and confidential EPC

Radio Frequency Identification technology (RFID) has a wide range of potential applications and many successful stories. However, there are certain issues regarding Electronic Product Code (EPC) network architecture and tag-reader security models, such as security, privacy and scalability of the EPC network whilst authenticating RF tags. The EPC network architecture specification has no authentication process to authenticate an RF tag prior to knowing its EPC, but a tag is authenticated at EPC information Service (EPCIS) instead. This may result in the leakage of tags EPC before its authentication. There is a need of an authentication process in the EPC network so that tags EPC may only be known once it is successfully authenticated. In this paper we have proposed an authentication broker service for EPC network. A distributed design of the authentication broker service is also discussed.