The open and broadcast nature of wireless channels leads to the inherent security problem of information leakage in wireless communication. We can utilize endogenous security functions to resolve this problem. The fundamental solution is channel-based mechanisms, like physical layer secret keys. Unfortunately, current investigations have not fully exploited the randomness of wireless channels, making secret key rates not high. Consequently, user data can be encrypted by reducing the data rate to match the secret key rate. Based on the analysis of the endogenous wireless security principle, we proposed that the channel-based endogenous secret key rate can nearly match the maximum data rate in the fast-fading environments. After that, we validated the proposition in an instantiation system with multiple phase shift keying (MPSK) inputs from the perspectives of both theoretical analysis and simulation experiments. The results indicate that it is possible to accomplish the onetime pad without decreasing the data rate via channel-based endogenous keys. Besides, we can realize high-speed endogenously secure transmission by introducing independent channels in the domains of frequency, space, or time. The conclusions derived provide a new idea for wireless security and promote the application of the endogenous security theory.
The open and broadcast nature of wireless channels leads to the inherent security problem of information leakage in wireless communication. We can utilize endogenous security functions to resolve this problem. The fundamental solution is channel-based mechanisms, like physical layer secret keys. Unfortunately, current investigations have not fully exploited the randomness of wireless channels, making secret key rates not high. Consequently, user data can be encrypted by reducing the data rate to match the secret key rate. Based on the analysis of the endogenous wireless security principle, we proposed that the channel-based endogenous secret key rate can nearly match the maximum data rate in the fast-fading environments. After that, we validated the proposition in an instantiation system with multiple phase shift keying (MPSK) inputs from the perspectives of both theoretical analysis and simulation experiments. The results indicate that it is possible to accomplish the onetime pad without decreasing the data rate via channel-based endogenous keys. Besides, we can realize high-speed endogenously secure transmission by introducing independent channels in the domains of frequency, space, or time. The conclusions derived provide a new idea for wireless security and promote the application of the endogenous security theory.
The open and broadcast nature of wireless channels makes eavesdropping possible, leading to the inherent problem of information leakage. Inherent problems should be solved by endogenous security functions. Accordingly, wireless security problems should be resolved by channel-based endogenous security mechanisms. Firstly, this paper analyzes the endogenous security principle of the physical-layer-secret-key method. Afterward, we propose a novel conjecture that in a fast-fading environment, there must exist wireless systems where the endogenous secret key rate can match the user data rate. Moreover, the conjecture is well founded by the instantiation validation in a wireless system with BPSK inputs from the perspectives of both theoretical analysis and simulation experiments. These results indicate that it is possible to accomplish the one-time pad via endogenous secret keys in wireless communication.
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.
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.
Secret key generation at physical layer has attracted more and more attentions as an emerging cryptography method. Compared to traditional security approaches, secret key generation at physical layer not only avoids the problem of key distribution, but also holds high efficiency and low complexity in application. Based on the principle of channel reciprocity, Alice and Bob both estimate the channel conditions and extract shared keys from this source of common randomness. In this paper, we first analyze the basic steps (channel estimation, sample quantization and key reconciliation) of secret key generation, key match rate with different quantization levels and key reconciliation times are also simulated. While in practical situations, different non-reciprocity factors affect the channel estimation step, key match rate can be greatly decreased and hardly meet real time cryptography requirements. In order to increase the key match rate, the unified framework of physical layer key generation has been extended to utilizing multiple observations of wireless channels to generate secret keys. An improved key generation approach with multiple observations can well deal with discrepancies between transceivers and keep increasing the key match rate. Theoretical analysis and simulation results both validate the significant improvement due to multiple observations. With an increased number of observations on both sides, the desired key match rate can be achieved much greater than with a single observation, and also the probability of key recovery by Eve can be decreased.
At present, wireless communication technology greatly improves the transmission data rate, but at the same time, it also has higher and higher requirements for the realization of secure communication. From the perspective of information theory, the physical layer key system provides a new way to solve the problem of secure communication in wireless communication system. The uplink and downlink wireless channels with natural reciprocity are used as random sources to generate shared key. Firstly, this paper introduces the steps of a key distribution protocol with multi-level quantization based on the characteristics of wireless channel CSI. Secondly, the security of this kind of key distribution protocol is analyzed by the key generation rate and other evaluation metrics. Furthermore, it is verified by simulation in the typical channel model scenario of 4G communication mode. The simulation results show that the key distribution protocol based on the characteristics of wireless channel can achieve a key generation rate of 5 bits/resource block under the condition of high signal-to-noise ratio (such as 20dB) in the current communication network circumstance, and the generated key sequence has sufficient randomness, so as to achieve effective secure communication.
It is vitally important to generate keys and keep them secret in secure wireless communications. Due to the broadcast nature of wireless channels, secret key distribution is more vulnerable to attacks in wireless communication. An ingenious solution is to generate secret keys by using the multipath channel as a source of common randomness. To address the problems that the existing physical-based protocols have low key generation rate and high reliance on mobile nodes or environments, a fast secret key generation protocol with virtual channel approach was proposed by HUANG and WANG for static wireless networks. In this paper, we show that, in the presence of an eavesdropper with multiple antennas, the scheme does not improve the theoretical upper bound of the key generation rate with information-theory security. Thus, the protocol is not information-theory security.