Wireless physical layer key generation is a remarkable technology for physical layer security. The security of key generation is not guaranteed in existing wireless physical layer key generation schemes if the eavesdropper is less than half a wavelength away from the legitimate node, which called non-secure zones problem. To address this problem, this paper proposes a Wireless physical layer key generation scheme based on unscheduled forwarding signal (WKG-UFS). Specifically, the legitimate communication nodes send random signals to each other within a coherent time. Then, the received signals are forwarded back within the coherent time after a random time interval. The legitimate nodes estimate the equivalent channel based on the final received signal and generate the secure key. Since eavesdropper does not know the original signals sent by the legitimate communication nodes, the channel feature cannot be effectively estimated. The results of theoretical analysis and experimental simulation show that the proposed scheme can effectively reduce the threat of eavesdropping on secure communication. Besides, since the time intervals for receiving and forwarding signals are variable, it can also effectively resist active attacks which by manipulating the channel.
Wireless physical layer key generation is a remarkable technology for physical layer security. The security of key generation is not guaranteed in existing wireless physical layer key generation schemes if the eavesdropper is less than half a wavelength away from the legitimate node, which called non-secure zones problem. To address this problem, this paper proposes a Wireless physical layer key generation scheme based on unscheduled forwarding signal (WKG-UFS). Specifically, the legitimate communication nodes send random signals to each other within a coherent time. Then, the received signals are forwarded back within the coherent time after a random time interval. The legitimate nodes estimate the equivalent channel based on the final received signal and generate the secure key. Since eavesdropper does not know the original signals sent by the legitimate communication nodes, the channel feature cannot be effectively estimated. The results of theoretical analysis and experimental simulation show that the proposed scheme can effectively reduce the threat of eavesdropping on secure communication. Besides, since the time intervals for receiving and forwarding signals are variable, it can also effectively resist active attacks which by manipulating the channel.
Abstract This paper focuses on high efficiency secret key generation mechanism of physical‐layer communication over fading channels in ubiquitous wireless networks. The secret key rate via traditional physical‐layer approach could be limited when the wireless propagation channels connecting two sensors change slowly. To generate a high‐rate secret key and improve the communication efficiency over quasi‐static block fading channels, a novel multi‐randomness device‐to‐device secret key generation strategy and a cooperative communication mechanism aided by relay nodes are proposed. In the proposed schemes, the legitimate members to send random signals rotationally in every coherent time are set; thus, two legitimate ubiquitous wireless network members, Alice and Bob, can obtain the potential correlated information by exploiting the randomness and the reciprocity of the wireless propagation channels. Considering the reciprocity of wireless channels is variable while the forward channel gain and backward channel gain are correlated in coherent time, a modified secret key generation scheme is proposed via layered coding with theoretical secret key rates derived. The simulation results show that the proposed scheme outperforms traditional approaches with favourable application prospects in ubiquitous wireless communications networks and internet of things.
Physical-layer key generation technology requires information reconciliation to correct channel estimation errors between two legitimate users. However, sending the reconciliation signals over the public channel increases the communication overhead and the risk of information leakage. Aiming at the problem, integrated secure communication schemes using non-reconciled keys have attracted extensive attention. These schemes exploit channel coding to correct both inconsistent keys and transmission error bits. Meanwhile, more redundant code bits must be added to correct errors, which results in a lower secure transmission rate. To address the problem, we analyze the merit of channel correlation between non-reconciled key generation and secure transmission. Inspired by this, we propose a non-reconciled physical-layer keys-assisted secure communication scheme based on channel correlation. First of all, the signal frame is designed to make use of channel correlation between non-reconciled key generation and secure transmission. Based on the channel correlation, non-reconciled keys are then generated from the wireless channel to encrypt transmitted data. Moreover, an adaptive coding algorithm based on the equivalent channel is presented to encode the data bits before encryption, to guarantee reliable transmission. Finally, theoretical analysis and simulations demonstrate the significant performance of the proposed scheme in terms of low bit error ratio and high secure transmission rate.
Encryption schemes for network security usually require a key distribution center to share or distribute the secret keys, which is difficult to deploy in wireless networks without fixed infrastructure. A novel key generation scheme based on the physical layer can generate a shared key between a pair of correlated parties by sharing random sources. The existing physical layer key generation scheme is based on the half-duplex mode with time division duplex (TDD) mode, which makes it impossible for the correlated communication parties to detect the channel simultaneously in order to improve the channel coherence. In this paper, we propose a full-duplex physical layer key generation scheme, which allows each legal communication nodes to transmit and receive signals at the same time, in order to reduce channel probing time and increase channel coherence performance. The simulation experiments show that the proposed scheme can much outperform some typical existing schemes in terms of the key performance evaluation indicators, key disagreement rate, key generation rate, entropy of the scheme improved, and the randomness of generated keys passed the National Institute of Standards and Technology (NIST) test.
The physical layer key generation technique provides an efficient method, which utilizes the natural dynamics of wireless channel. However, there are some extremely challenging security scenarios such as static or quasi-static environment, which lead to the low randomness of generated keys. Meanwhile, the coefficients of the static channel may be dropped into the guard space and discarded by the quantization approach, which causes low key generation rate. To tackle these issues, we propose a random coefficient-moving product based wireless key generation scheme (RCMP-WKG), where new random resources with remarkable fluctuations can be obtained by applying random coefficient and by moving product on the legitimate nodes. Furthermore, appropriate quantization approaches are used to increase the key generation rate. Moreover, the security of our proposed scheme is evaluated by analyzing different attacks and the eavesdropper's mean square error (MSE). The simulation results reveal that the proposed scheme can achieve better performances in key capacity, key inconsistency rate (KIR) and key generation rate (KGR) compared with the prior works in static environment. Besides, the proposed scheme can deteriorate the MSE performance of the eavesdropper and improve the key generation performance of legitimate nodes by controlling the length of the moving product.
Secret group key generation based on physical layer in wireless communications has a lot of practical applications. A few studies focused on the theoretical bounds of the secret key rate based on the sets of received signals rather than a particular secret key generation scheme. We propose a secret group key generation scheme for an arbitrary number of legitimate nodes, n, in mesh topology in the presence of a passive eavesdropper. In the scheme, after general pilot signal transmissions at all nodes, each node broadcasts a weighted combination of its received signals with optimized coefficients, so that legitimate nodes can obtain the information of channels used for group key generation while the eavesdropper cannot. We also apply different quantization schemes for quantizing and encoding the estimated channels into keys. To provide detailed transmissions and processing steps of group key generation, we also describe the proposed scheme for 4-node mesh topology case. The simulation results show that the proposed scheme achieves a higher secret group key rate and a lower key disagreement rate than a benchmark scheme.
Secret group key generation based on physical layer in wireless communications has a lot of practical applications. A few studies focused on the theoretical bounds of the secret key rate based on the sets of received signals rather than a particular secret key generation scheme. We propose a secret group key generation scheme for an arbitrary number of legitimate nodes, n, in mesh topology in the presence of a passive eavesdropper. In the scheme, after general pilot signal transmissions at all nodes, each node broadcasts a weighted combination of its received signals with optimized coefficients, so that legitimate nodes can obtain the information of channels used for group key generation while the eavesdropper cannot. We also apply different quantization schemes for quantizing and encoding the estimated channels into keys. To provide detailed transmissions and processing steps of group key generation, we also describe the proposed scheme for 4-node mesh topology case. The simulation results show that the proposed scheme achieves a higher secret group key rate and a lower key disagreement rate than a benchmark scheme.