Key Error Rates in Physical Layer Key Generation: Theoretical Analysis and Measurement-Based Verification

Abstract

Channel gains are frequently used to obtain a secret key that can be used for encryption in physical layer security systems. However, the channel gains captured by the nodes may not always be the same due to channel estimation errors. This would result in a non-zero key error rate (KER). In this letter, we obtain theoretical expressions for KER in orthogonal frequency division multiplexing systems. Tight KER approximations are provided based on Gauss-Laguerre quadrature. A measurementbased study is conducted by using software defined radio nodes to demonstrate the validity and the practicality of the provided results.

Efficient physical layer key generation technique in wireless communications

“…Therefore, Bob should respond quickly after receiving quickly the probing signal. By repeatedly exchanging transmit probe signals over timevarying channel, Alice and Bob can derive a sequence of n channel estimates h a = ( h a [ 1] , h a [ 2] , [10]. Theoretically, these sequences are highly correlated.…”

“…Step 2: Calculate the guard-band of each interval. Alice counts the distribution of the input sequences in each interval, and then calculates the mean mean = (mean [ 1] , mean [ 2] [ i] denote the mean and standard deviation of ith interval, respectively. Similarly, we assume that N = 2, then the guard-band of each interval is shown in Fig.…”

“…However, conventional mechanisms may not be suitable for certain scenarios (e.g., sensor networks, cognitive radio networks, and vehicular networks) because low-energy devices cannot afford the high resource overheads. As an alternative method, the physical layer characteristics [2,3]-based key generation has been designed. Different from traditional public key cryptography, the physical layer key generation schemes do not require expensive computation.…”

“…Different from traditional public key cryptography, the physical layer key generation schemes do not require expensive computation. It is possible to achieve information-theoretic security because the confidentiality of the generated key does not *Correspondence: xuli@fjnu.edu.cn 1 College of Mathematics and Informatics, Fujian Normal University, Fuzhou, Fujian, China 2 Fujian Provincial Key Laboratory of Network Security and Cryptology, Fuzhou, Fujian, China Full list of author information is available at the end of the article depend on the hardness of the computational problem but relies on the physical characteristics of the wireless fading channels [4]. More importantly, the physical layer key generation technique can dynamically establish a shared key between a pair of transceivers through exploring the channel reciprocity and variations.…”

Wireless Key Generation from Imperfect Channel State Information: Performance Analysis and Improvements

“…However, a common drawback of these works is lack of theoretical analysis to provide an insight into the key generation performance. In [12], an approximation for KDR is obtained based on Gauss-Laguerre quadrature. Nonetheless, this result is not closed-form, and only the impact of estimation error is taken into account, without that of time delay.…”