认知无线电网络中基于接收信号强度的组密钥提取方案

Group Secret Key Extraction Scheme Based on Received Signal Strength in Cognitive Radio Networks

为了保障认知无线电网络(cognitive radio networks, CRNs)中次用户之间的安全通信,提出一种基于物理层无线信道特征接收信号强度(received signal strength, RSS)的组密钥提取方案。在网络中并非所有次用户都在彼此通信范围内的情况下,该方案利用中继节点实现组密钥的提取,即在链式通信拓扑结构下,组内所有节点将链上除头节点和尾节点以外的其他节点作为辅助中继节点,提取链上所有相邻节点间的RSS测量值。之后,提出一种新的量化方法对提取到的RSS测量值进行量化。首先,给所有RSS测量值找到相应的量化区间;其次,为每个RSS测量值找到相配对的值,使得生成的密钥与多位RSS测量值相关,保证最终密钥生成的随机性;最后,利用格雷码编码对量化后的RSS测量值进行编码。使用MATLAB仿真软件模拟用户在高斯信道中建立组密钥的过程,信噪比在0~30 dB变化,实验结果表明,密钥建立过程中比特不一致率随着组内节点个数增加而增加,随着信噪比的增大而减小。此外,数值计算分析了该方案在不同条件下能够达到的组密钥率,结果表明,该方案的组密钥率随着组内节点个数和信噪比变化所呈现的变化趋势与比特不一致率相反。与现有方案相比,本方案能够大幅地降低用户建立组密钥的通信代价。综上所述,本方案在提高组密钥提取效率和降低用户通信代价方面都具有较明显的优势。

To secure the communications in cognitive radio networks (CRNs), a group secret key extraction scheme based on received signal strength (RSS) was proposed. This scheme employed relay nodes to extract a group secret key in the chain topology. Be more specific, nodes oth- er than the head and the tail were considered as relay nodes, of which the RSS measurement of each adjacent pair was extracted. Then, each RSS measurement was quantified referring to predetermined thresholds to ensure the randomness of the generated key which was multiple RSS meas- urements related. Finally, the gray code was utilized to encode the quantified RSS measurements. In this paper, MATLAB was used to simulate the process of users establishing group secret key in Gaussian channel. By setting different levels of noise, the signal-to-noise ratio (SNR) varied from 0 dB to 30 dB. The results showed that the bit inconsistency rate increased with the number of nodes in the group and decreased with the in- crease of SNR. At the same time, the key generation rate of the proposed scheme under different conditions was analyzed by numerical analysis. It showed that the group secret key rate varied with the number of nodes in the group and SNR, which was opposite to the bit inconsistency rate. The proposed scheme outperforms contemporary ones with higher extraction efficiency and a lower communication cost as well.