Malicious Eavesdroppers Research Articles

Joint Relay and Jammer Selection and Power Control for physical Layer Security in Two-Way Relay Networks with Imperfect CSI

Physical layer security is an emerging security paradigm that can achieve secure information transmission from the source to the intended destination with the existence of malicious eavesdroppers. In this paper, joint relay/jammer selection and power control with friendly jammers for physical layer security in two-way relay networks are studied. First, several relay/jammer selection schemes are proposed to increase the secrecy capacity for source nodes and degrade the eavesdropper links simultaneously. The presented schemes select one conventional relay node and at most two friendly jammers among a number of intermediate nodes. The impact of channel estimation error on the wiretap channel is also considered. After the selection of optimal relay node and friendly jammers, a game-theoretic power control approach is introduced to deal with the interaction between the source nodes and the friendly jammers. The proposed power control approach is proven to be able to converge to the Stackelberg equilibrium, and both source nodes and friendly jammers can obtain their optimal benefits. The simulation results demonstrate the effectiveness of the relay/jammer selection schemes to enhance the secrecy capacity of the system, and validate the properties of optimization and convergence for the game-theoretic power control approach.

Secrecy Capacity Optimization via Cooperative Relaying and Jamming for WANETs

Cooperative wireless networking, which is promising in improving the system operation efficiency and reliability by acquiring more accurate and timely information, has attracted considerable attentions to support many services in practice. However, the problem of secure cooperative communication has not been well investigated yet. In this paper, we exploit physical layer security to provide secure cooperative communication for wireless ad hoc networks (WANETs) where involve multiple source-destination pairs and malicious eavesdroppers. By characterizing the security performance of the system by secrecy capacity, we study the secrecy capacity optimization problem in which security enhancement is achieved via cooperative relaying and cooperative jamming. Specifically, we propose a system model where a set of relay nodes can be exploited by multiple source-destination pairs to achieve physical layer security. We theoretically present a corresponding formulation for the relay assignment problem and develop an optimal algorithm to solve it in polynomial time. To further increase the system secrecy capacity, we exploit the cooperative jamming technique and propose a smart jamming algorithm to interfere the eavesdropping channels. Through extensive experiments, we validate that our proposed algorithms significantly increase the system secrecy capacity under various network settings.

Cooperative Secure Resource Allocation in Cognitive Radio Networks with Guaranteed Secrecy Rate for Primary Users

In this paper, we introduce a new cooperative paradigm for secure communication in cognitive radio networks (CRNs) where secondary users (SUs) are allowed to access the spectrum of primary users (PUs) as long as they preserve the secure communication of PUs in the presence of malicious eavesdroppers. To do so, the SU transmission is divided into two hops: at first hop, the SU transmitter sends the information to a relay set and the SU receiver acts as a friendly jammer to disturb the overhearing of eavesdroppers and at the second hop, one of the relays is selected to pass the information to the SU receiver and the SU transmitter acts as a friendly jammer for the PU. In this new setup, the time duration for each hop, the power transmissions of all nodes in CRN, and relay selection at the second hop are allocated in such a way that the secrecy rate of the SU is maximized subject to the minimum required PU's secrecy rate. From primary service perspective, this transforms the possibly disturbing secondary service activities into a beneficial network element. We investigate instantaneous and ergodic resource allocation problems for perfect and imperfect channel state information (CSI). Since these problems are non-convex, we propose a solution based on decomposition of main optimization problem into three subproblems related to the power allocation, time allocation, and relay selection. We show that the power allocation problem can be transformed into a generalized geometric programming (GGP) model via the so-called scaled algorithm and it can be solved very efficiently. Simulation results indicate that in terms of the secondary secrecy rate, the proposed setup outperforms the conventional setup in which the secrecy rate of the PU is not guaranteed.

Enhancing Secrecy With Multi-Antenna Transmission in Wireless Ad Hoc Networks

We study physical-layer security in wireless ad hoc networks and investigate two types of multi-antenna transmission schemes for providing secrecy enhancements. To establish secure transmission against malicious eavesdroppers, we consider the generation of artificial noise with either sectoring or beamforming. For both approaches, we provide a statistical characterization and tradeoff analysis of the outage performance of the legitimate communication and the eavesdropping links. We then investigate the network-wide secrecy throughput performance of both schemes in terms of the secrecy transmission capacity, and study the optimal power allocation between the information signal and the artificial noise. Our analysis indicates that, under transmit power optimization, the beamforming scheme outperforms the sectoring scheme, except for the case where the number of transmit antennas are sufficiently large. Our study also reveals some interesting differences between the optimal power allocation for the sectoring and beamforming schemes.

A New Relay and Jammer Selection Schemes for Secure One-Way Cooperative Networks

This paper presents different relay and jammer selection schemes for one-way cooperative networks to increase the security against malicious eavesdroppers. We consider a single source-destination cooperative network with multiple intermediate nodes and one or more eavesdroppers. The selection in the proposed schemes is made with the presence of direct links and the assumption that the broadcast phase is unsecured. The proposed schemes select three intermediate nodes. The first selected node operates in the conventional relay mode and assists the source to deliver its data to the corresponding destination via a Decode-and-Forward strategy. The second and third selected nodes are used in different communication phases as jammers to create intentional interference at the eavesdroppers' nodes. Moreover, a hybrid scheme which switches between jamming and non-jamming modes is introduced in this paper. The proposed schemes are analyzed in terms of ergodic secrecy capacity and secrecy outage probability. Extensive analysis and a set of simulation results are presented to demonstrate the effectiveness of the different schemes presented in this work. The obtained results show that the proposed schemes with jamming outperform the conventional non-jamming schemes and the hybrid switching scheme further improves the secrecy capacity. The impact of changing both the eavesdroppers and the relays location on ergodic secrecy capacity and secrecy outage probability is also discussed. Finally, the impact of the presence of multiple eavesdroppers is studied in this paper.

Optimizing mix-zone coverage in pervasive wireless networks1

Location privacy is a major concern in pervasive networks where static device identifiers enable malicious eavesdroppers to continuously track users and their movements. In order to prevent such identifier-based tracking, devices could coordinate reg

Optimizing mix-zone coverage in pervasive wireless networks

Location privacy is a major concern in pervasive networks where static device identifiers enable malicious eavesdroppers to continuously track users and their movements. In order to prevent such id...

Dummy rate analysis of buffer constrained chaum mix

Providing anonymity to network communication refers to the prevention of “networking information” retrieval, not only using the content of transmitted data packets but also from their timing information. Access to such timing information can reveal the source-destination pairs or path of data flow which is a violation of user privacy, and can further be used to jam a particular flow or create black holes. Chaum Mixes [1] are often used to obfuscate this timing information from malicious eavesdroppers. A Chaum Mix is a relay node or a proxy server that collects packets from different users, then uses layered encryption and packet padding to make outgoing packets appear indistinguishable to eavesdroppers. Furthermore, it also alters the timing information by reordering and batching together packets from different users, so that the probability of any outgoing packet belonging to a particular user is identical for all users, thus achieving perfect anonymity. A drawback of the ideal Chaum Mix is that if long data streams (eg. media streaming) are transmitted, then it may require a very large buffer capacity to work well. In fact, it has been proven that any batching strategy, under the constraint of a limited buffer size, would eventually reveal the source identities [2]. It is, however, possible to mask the actual pattern of traffic flow through the insertion of dummy traffic. For example, consider a network where all nodes transmit packets according to scheduled departure times. If an actual packet is unavailable for transmission at its time of departure, a dummy packet can be transmitted in its place and perfect anonymity is still maintained. But the extensive use of dummy packets can reduce network throughput, which leads to some interesting questions:

A dependable privacy protection for end-to-end VoIP via Elliptic-Curve Diffie-Hellman and dynamic key changes

Voice over IP (VoIP) service has been widely deployed over the prevalent Internet due to the advanced technologies of digital voice compression, communication protocols, and wired/wireless networks. VoIP then benefit much lower cost of equipment, operation, and better integration with data applications than voice communications over telephony networks. On the other hand, VoIP further introduce security vulnerability while delivering voice packets over the public Internet, using the transparent IP protocol suite. The most popular solution to secure VoIP voice packets is to apply cost-effective AES encryption with a single key during to a voice call. In this paper, to further enhance the VoIP security to prevent malicious eavesdroppers, we propose a much stronger privacy protection for an end-to-end VoIP. This dependable solution applies not only the Elliptic-Curve Diffie-Hellman (ECDH) algorithm for key negotiation, but also the key generation function (KGF) for changing key dynamically in a VoIP call session. This 2-tier key distribution scheme provides effective and robust security for VoIP voice packets during the end-to-end call session. This proposed scheme has been deployed on an opensource SIP-based phone as our test-bed over the Internet. The performance results from the experiments with the Internet dynamics of packet loss inserted on the test-bed demonstrate that the proposed scheme not only provide more secure VoIP call, but also preserve the quality of voice packet delivery.

Aegis: Physical Space Security for Wireless Networks With Smart Antennas

In this paper, we focus on securing communication over wireless data networks from malicious eavesdroppers by using smart antennas. While conventional cryptography-based approaches focus on hiding the meaning of the information being communicated from the eavesdropper, we consider a complimentary class of strategies that limit knowledge of the existence of the information from the eavesdropper. We profile the performance achievable with simple beamforming strategies using a newly defined metric called exposure region. We then present three strategies within the context of an approach called <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Aegis</i> , which uses virtual arrays of physical arrays to significantly improve the exposure region performance of a wireless LAN environment. Using simulations, analysis, and field trials, we validate and evaluate the proposed strategies.

A Privacy Enabled Fast Dynamic Authentication and Authorization for B3G/4G Mobility

Mobile technologies make their headway by offering more flexibility to end-users and improve the productivities. Within the application of ubiquitous access and pervasive communication, security (or privacy) and QoS (Quality of Service) are two critical factors during global mobility, so how to get a smooth and fast handover based on a user privacy protected infrastructure is our focus. Based on a user-centric vir-tual identity defined by EU IST project Daidalos, this paper firstly proposes an effective infrastructure which protects the context-driven access policies for online services in order to avoid attacks by malicious eaves-droppers. In the proposed infrastructure, SMAL and Diameter are used to securely protect and deliver au-thenticated and authorized entities and XACML is used to authorize the user-level privacy policy. On the basis of it, a dynamic fast authentication and authorization handover mechanism is proposed which can save one trip communication time consummation between administrative domains.