Muhammad Faisal Amjad

Transparent cross-layer solutions for throughput boost in Cognitive Radio Networks

Cognitive Radio Network (CRN) is an emerging paradigm that makes use of Dynamic Spectrum Access (DSA) to communicate opportunistically, in the un-licensed Industrial, Scientific and Medical bands or frequency bands otherwise licensed to incumbent users such as TV broadcast. The opportunistic mode of data transfer introduces network-wide quiet periods for spectrum sensing and increased packet losses due to activities by Primary Users. TCP attributes packet delays and losses to congestion in the Internet, which does not perform well in wireless networks where the medium has inherent higher error rates than wired Internet. Opportunistic mode of communication in CRNs aggravates the already error-prone wireless communication resulting in further degradation of TCP performance due to higher latency and decreased throughput. This paper presents an analysis of TCP performance in IEEE 802.22 Wireless Regional Area Network (WRAN) based on Cognitive Radio Networks and proposes two approaches to improve the networking performance. The first approach makes base station resort to local recovery of lost frames between CRN base station and its clients, while the second approach implements a modified split TCP connection in which the base station sends crafted acknowledgements back to an Internet-side host on behalf of the corresponding CRN client to boost transmission speed. To the best of our knowledge, this is the first effort to study TCP performance in IEEE 802.22 based WRANs. Simulation results show that the proposed mechanisms result in improvement in TCP performance by as much as 20 times and conserve bandwidth by reducing retransmission overheads.

User-side Wi-Fi Evil Twin Attack detection using SSL/TCP protocols

Evil Twin Attack (ETA) refers to a rogue Wi-Fi Access Point (AP) that appears to be a legitimate one but actually has been set up to eavesdrop on wireless communications [1]. Most of existing detection techniques assume that the attacker will use the same legitimate wireless network gateway to pass through victims wireless data. These detection methods will fail if the attacker uses a different gateway, such as using his own broadband cellular connection through his own smartphone. In this paper, we present a new client-side detection method to detect such an ETA that uses a different gateway from the legitimate one. It relies on SSL/TCP connection to an arbitrary remote web server to avoid attackers misleading message, and trying to detect the changing of gateways public IP address by switching from one AP to another in the middle of the SSL/TCP connection. The detection method is on the client side which makes it more convenient for users to deploy and ensure their security.

Inducing Cooperation for Optimal Coexistence in Cognitive Radio Networks: A Game Theoretic Approach

Current coexistence protocols employed for contention by collocated Cognitive Radio Networks (CRN), such as the IEEE 802.22 WRAN, assume that the contending networks do not have any preference over the set of available channels. Having channels with different quality parameters can lead to an imbalance in contention for disparate channels, degraded quality of service and an overall inefficient utilization of spectrum resources. In this paper, we analyze this situation from a game theoretic perspective and model coexistence of CRNs as a non-cooperative, repeated general-sum game with perfect information. We demonstrate that due to the possibility of its centralized as well as a distributed implementation, the correlated equilibrium is a practical solution for the problems of inefficiency and unfairness of Nash Equilibria. It not only induces voluntary cooperation among non-cooperative CRNs and results in optimum spectrum utilization but also results in an egalitarian equilibrium which maximizes the minimum payoff for every CRN.

Coexistence in heterogeneous spectrum through distributed correlated equilibrium in cognitive radio networks

Coexistence protocols enable collocated cognitive radio networks (CRNs) to share the spectrum in an opportunistic manner. These protocols work under the assumption that all spectrum bands provide the same level of throughput. This assumption is however limited in scope because channel conditions as well as the licensees usage of allocated channels can vary significantly with time and space. Under these circumstances, CRNs are expected to have a preference over the choice of available channels which can lead to an imbalance in contention for disparate channels, degraded quality of service, and an overall inefficient utilization of spectrum resource. In this paper, we analyze this situation from a game theoretic perspective and model the coexistence of CRNs with heterogeneous spectrum as a non-cooperative, repeated spectrum sharing game. We derive three solutions for the game; (1) pure and (2) mixed strategy Nash Equilibria as well as (3) centralized and distributed correlated equilibria which are derived using linear programming and a channel selection learning algorithms, respectively. We also analyze each of these solutions from the perspective of fairness and efficiency. To that end, we utilize the concept of price of anarchy to measure the efficiency of these solutions under selfish behavior from CRNs.

Algebraic Side Channel Attack on Trivium and Grain Ciphers

Solving a system of multivariate quadratic equations obtained through algebraic cryptanalysis is a nondeterministic polynomial time-complete problem. Owing to the trend of stream ciphers based on nonlinear update, the success of algebraic attacks has been limited to their reduced variants. On the other hand, side channel attacks (SCAs), although require a continued access to the target device for capturing leakages, are a potent threat against the stream ciphers. Algebraic SCA (ASCA) combines and solves equations obtained through algebraic cryptanalysis and partial SCA of cipher implementation. ASCA is successfully being applied against block ciphers since 2009; however, there is no existing published work on ASCA against stream ciphers as per our knowledge. In this paper, we propose an idea of mounting ASCA on stream ciphers, and we demonstrated it through the application of ASCA on trivium and grain stream ciphers.

Gateway independent user-side wi-fi evil twin attack detection using virtual wireless clients

Abstract Complimentary open Wi-Fi networks offered by most coffee shops, fast food restaurants and airports are inherently insecure. An attacker can easily deceive a wireless client (WC) by setting up a rogue access point (RAP) impersonating the legitimate access point (LAP), which is usually referred as Evil Twin Attack (ETA). To pass a victims wireless data through to the Internet, an attacker may use the same LAPs gateway, or use a different gateway, such as broadband cellular connection. Most of the existing ETA detection techniques assume that the attacker will use a specific wireless network gateway to pass victims wireless data. In this paper, we present a real-time client-side detection scheme to detect ETA regardless of the attackers gateway selection. The proposed ETA detection system considers both ETA scenarios in parallel by creating two Virtual Wireless Clients (VWCs). The first VWC monitors multiple Wi-Fi channels in a random order looking for specific data packets sent by a server on the Internet. Meanwhile, the second VWC warns the WC when the wireless network uses two different gateways by switching from one AP to another in the middle of a secure connection. The effectiveness of the proposed detection method has been mathematically modeled, prototyped and evaluated in real-life environment with a detection rate close to 100%.

Combining algebraic and side channel attacks on stream ciphers

A cryptanalysis technique can be termed successful if its complexity is better than brute force attack, even though it may not be practically feasible due to high complexity. However, it is a proven fact that combining different type of attack techniques in past has paid dividends with regards to overall complexity. We, in this paper propose novel idea of combining algebraic and side channel attacks on stream ciphers. Algebraic cryptanalysis has a high cost when pitched against stream ciphers with nonlinear update and for side channel attacks, adversary needs to have a continued access to ciphers implementation. On the other hand combining both these attacks can overcome their individual shortcomings to a great extent, thereby making it practically feasible. Algebraic and side channel attacks have been earlier combined on block ciphers, but no work on applying such attacks against stream ciphers has been published so far.

Evolutionary non-cooperative spectrum sharing game: long-term coexistence for collocated cognitive radio networks†

Collocated cognitive radio networks (CRNs) employ coexistence protocols to share the spectrum when it is not being used by the licensed primary users. These protocols work under the assumption that all spectrum bands provide the same level of quality of service, which is somewhat simplistic because channel conditions as well as the licensees usage of allocated channels can vary significantly with time and space. These circumstances dictate that some channels may be considered better than others; therefore, CRNs are expected to have a preference over the choice of available channels. Because all CRNs are assumed to be rational and select the best available channels, it can lead to an imbalance in contention for disparate channels, degraded quality of service, and an overall inefficient utilization of spectrum resource. In this paper, we analyze this situation from a game theoretic perspective and model the coexistence of CRNs with heterogeneous spectrum as an evolutionary anti-coordination spectrum-sharing game. We derive the evolutionarily stable strategy (ESS) of the game by proving that it cannot be invaded by a greedy strategy. We also derive the replicator dynamics of the proposed evolutionary game, a mechanism with which players can learn from their payoff outcomes of strategic interactions and modify their strategies at every stage of the game and subsequently converge to ESS. Because all CRNs approach ESS based solely upon the common knowledge payoff observations, the evolutionary game can be implemented in a distributed manner. Finally, we analyze the game from the perspective of fairness using Jains fairness index under selfish behavior from CRNs. Copyright

Forensic investigation to detect forgeries in ASF files of contemporary IP cameras

Recent years have seen tremendous increase in crime and terrorism all over the world which has necessitated continuous surveillance of public spaces, commercial entities and residential areas. CCTV cameras are an integral part of any modern surveillance system and have evolved significantly. They are a vital part of any investigation that follows a criminal or terrorism incident by providing invaluable evidence. In this paper, we show that the Advance Systems Format (ASF) file used in most IP cameras, which is also the main file containing metadata about the streaming packets, is vulnerable to forgery. This file is stored in plain text and any technically savvy person can forge it; therefore, a mechanism is needed to prevent it. To that end, we have gathered critical artifacts from an ASF file of IP cameras and carried out their forensic analysis. The analysis performed during this study demonstrates successful detection of forgery/tampering of evidence in IP cameras.

Defence against PUE attacks in ad hoc cognitive radio networks: a mean field game approach

Cognitive Radio (CR) is an emerging and promising communication technology geared towards improving vacant licensed band utilization, intended for unlicensed users. Security of Cognitive Radio Networks (CRN) is a highly challenging domain. At present, plenty of efforts are in place for defining new paradigms, techniques and technologies to secure radio spectrum. In a distributed cognitive radio ad-hoc network, despite dynamically changing topologies, lack of central administration, bandwidth-constraints and shared wireless connections, the nodes are capable of sensing the spectrum and selecting the appropriate channels for communication. These unique characteristics unlock new paths for attackers. Standard security techniques are not an effective shield against attacks on these networks e.g. Primary User Emulation (PUE) attacks. The paper presents a novel PUE attack detection technique based on energy detection and location verification. Next, a game model and a mean field game approach are introduced for the legitimate nodes of CRN to reach strategic defence decisions in the presence of multiple attackers. Simulation of the proposed technique shows a detection accuracy of