Several key exchange methods for wireless channels have been presented in the literature. They are collectively named as PHY-layer security techniques and are usually based on the channel's fading characteristics and the reciprocity principle. In this paper, we present a PHY-layer security algorithm which includes channel sampling and thresholding and error reconciliation based on neural networks. The presented algorithm's performance and offers a security and these are studied with the help of simulations and interesting results are drawn about its overall utility.
Several key exchange methods for wireless channels have been presented in the literature. They are collectively named as PHY-layer security techniques and are usually based on the channel's fading characteristics and the reciprocity principle. In this paper, we present a PHY-layer security algorithm which includes channel sampling and thresholding and error reconciliation based on neural networks. The presented algorithm's performance and offers a security and these are studied with the help of simulations and interesting results are drawn about its overall utility.
Several key exchange methods for wireless channels have been proposed in the literature. They are referred to as PHY-layer security techniques and are usually based on the channel's fading characteristics and the principle of reciprocity. In this paper, we present a novel PHY-layer security algorithm whose function is based on neural networks. Specifically, we present a full key exchange scheme which includes channel sampling and thresholding and neural network based error reconciliation. The proposed method's performance and offered security are studied through simulations and interesting conclusions are drawn about its overall utility.
Several key exchange methods for wireless channels have been proposed in the literature. They are referred to as physical‐layer security techniques and are usually based on the channel's fading characteristics and the principle of channel reciprocity. In this study, the authors present key exchange algorithms for wireless fading channels whose operation is based on channel estimation. Specifically, the authors present a complete key exchange scheme that includes channel sampling, thresholding and error reconciliation. Two error reconciliation methods are proposed. The first one is based on neural networks and the second one is based on linear block coding. Simulations of the proposed methods’ performances and levels of security are presented and conclusions are drawn regarding their overall utility.
Due to the broadcast nature of wireless channels, wireless communication is vulnerable to eavesdropping, message modification, and node impersonation. Securing the wireless communication requires the shared secret keys between the communicating entities. Traditional security schemes rely on public key infrastructures and cryptographic algorithms to manage secret keys. Recently, many physical-layer-based methods have been proposed as alternative solutions for key generation in wireless networks. These methods exploit the inherent randomness of the wireless fading channel to generate secret keys while providing information-theoretical security without intensive cryptographic computations. This article provides an overview of the existing PHY-based key generation schemes exploiting the randomness of the wireless channels. Specifically, we first introduce the fundamental and general framework of the PHY-based key generation schemes and then categorize them into two classes: received-signal-strength-based and channel- phase-based protocols. Finally, we present a performance comparison of them in terms of key disagreement probability, key generation rate, key bit randomness, scalability, and implementation issues.
Due to the unavoidable shared nature of the wireless radio spectrum, providing security for wireless communications presents unique challenges. Cryptographic keys have been used as a primary technique for securing wireless networks but are not completely secure. The symmetric keys used for cryptographic purposes are vulnerable to man-in-the-middle and brute force attacks. More recently, PHY-layer based techniques have gained significant attention, where the principle of channel reciprocity and the natural randomness of the measured wireless channel to generate secret keys is leveraged. Although, PHY-layer secret key generation has been investigated and presented in the literature before, there has been a lack of discussion in terms of obtaining symmetric keys on both ends of the link. In this work, we present a novel PHY-layer secret key generation technique that aims for symmetric encryption keys while limiting the information leaked to an eavesdropper to ensure complete secrecy and to prevent potential intelligent attacks. Our algorithm utilizes forward and backward channel state information in a given wireless link and combats the minute differences observed in these pairs by generating channel trend information. We demonstrate our technique using experimental results from a realtime SDR testbed connected to a wireless channel emulator. Our results indicate that the algorithm is successful in generating symmetric keys under various wireless environments without revealing any information pertaining to the key via the open wireless channel. Our secret key extraction rate can reach values in excess of 17.3 Kbps.
Security is one of the key requirements of wireless communication systems. By exploiting the broadcast nature of wireless medium, a malicious user might attempt to mislead the legitimate nodes, intercept the communication and overhear the private information. In order to combat against such malicious attacks, various encryption using security techniques have been proposed in the literature. Recently, physical layer (PHY) security has emerged as an additional countermeasure to the encryption based approaches and become very popular. Unlike cryptography, PHY security techniques target to protect the signal itself rather than encrypting the information bits. However, most of these techniques are designed based on specific channel conditions. Since channel has a random nature and cannot be controlled by users, such a design approach may remain unreliable for many practical scenarios where the desired channel state does not exist. Therefore, in this study, we highlight the importance of the channel independent PHY security techniques. In order to draft the ongoing efforts and provide the open issues in this direction, three different concepts are discussed along with the reviews of sample studies.
As an alternative and appealing approach to providing information security in wireless communication systems, secret key generation at physical layer has demonstrated its potential in terms of efficiency and reliability over traditional cryptographic methods. Without the necessity of a management centre for key distribution or reliance on computational complexity, physical layer key generation protocols enable two wireless entities to extract identical and dynamic keys from the randomness of the wireless channels associated with them.\nIn this thesis, the reliability of secret key generation at the physical layer is examined in practical wireless channels with imperfect channel state information (CSI). Theoretical analyses are provided to relate key match rate with channel's signal-to-noise ratio (SNR), degrees of channel reciprocity, and iterations of information reconciliation.\nIn order to increase key match rate of physical layer secret key generation, improved schemes in the steps of channel estimation and sample quantization are proposed respectively. In the channel estimation step, multiple observations of the wireless channels are integrated with a linear processor to provide a synthesized and more accurate estimation of the wireless channel. In the sample quantization step, a magnitude based quantization method with two thresholds is proposed to quantize partial samples, where specific quantization areas are selected to reduce cross-over errors. Significant improvements in key match rate are proven for both schemes in theoretical analysis and numerical simulations. Key match rate can even achieve 100% in both schemes with the assistance of information reconciliation process.\nIn the end, a practical application of physical layer secret key generation is presented, where dynamic keys extracted from the wireless channels are utilized for securing secret data transmission and providing efficient access control.