A Study On Channel Key Generation Based On Physical Layer

With the development of wireless communication system,the requirements about the security of wireless communication system are becoming increasing higher and higher.By utilizing the characteristics of wireless physical channels,wireless devices could implement some functions such as data encryption,identification of legal and illegal users at the physical layer.This technology not only meets the various needs of modern production and life,but also provides applicable security guarantees for wireless communication systems.In recent years,the physical layer channel key research has attracted much attention from the industry and academia.However,the existing physical layer key generation methods have some problems in performance such as low key generation rate and weak key randomness.In order to alleviate the above problems,this paper proposes channel key generation methods based on Received Signal Strength(RSS).The main research contents are as follows:1.In the existing key extraction schemes based on RSS,due to the lossy quantization algorithm and the parameters of the quantization algorithm levels,the key generation rate is low.In order to solve the problem of low key generation rate,this paper proposes a physical layer wireless channel key generation scheme based on iterative quantization.In this solution,the RSS measurements collected by two wireless devices are used to obtain the keys through iterative quantization algorithm.The quantization algorithm has multiple rounds of quantization,and the algorithm will adaptively determine the quantization standard parameters of each round according to the input RSS measurements.In order to illustrate the practicability of the proposed scheme,we use RT2870 chip’s Ralink Wi Fi network card to implement the key generation process.Experimental results show that the proposed quantization algorithm can improve the utilization of RSS values,and also increase the key generation rate.2.In order to enhance the randomness of key generation in different scenarios,a key generation method based on adaptive quantization is proposed,which performs group quantization and adaptive quantization on the collected RSS measurements.The design of group quantization improves the randomness of the generated keys,and makes 0 and 1 in generated keys more evenly distributed.The advantage of adaptive quantization is to design an adaptive quantization interval.The wireless devices can select the appropriate quantized reference levels according to the RSS measurements in different scenarios.The scheme evaluates the performance of the generated key through experiments.The test results show that the generated key can pass 10 NIST test items,indicating that the wireless device can extract a strong random security key in different scenarios.In addition,this scheme is compared with other key generation schemes from various performance indicators.The comparison results show that the key generation of this scheme is better than other schemes in terms of randomness.