基于多信道特征提取的物理层密钥生成方法

Physical layer key generation scheme based on multi-channel characteristics sampling

为解决资源受限的物联网设备难以实现复杂的物理层密钥生成这一难题,文中利用ZigBee传感器设备信道快速切换能力,提出一种基于信号强度(RSS)和多信道共同采样的物理层密钥生成方法。首先借助多径时变信道的随机性,基于信道选择策略和探测协议,在2.4 GHz频段的多个通信子信道上对RSS进行多轮间隔采样;然后对采样值进行矩阵缓存、均值滤波及量化;最后通过密钥协商协议得到会话密钥。该方法创新性地将多信道RSS作为密钥生成特征信息,可有效降低特征采样值间的相关性及信道相干时间对采样速度的限制,从而大幅提升密钥的生成速率和一致性。实验结果表明,真实室内移动环境下,所提方法的密钥生成速率可达到10 bit/s以上,且能够对恶意攻击产生有效的抑制。该方法简单高效,易于在物联网设备上实现。

In allusion to the problem that it is difficult to generate complex physical layer key for resource-constrained devices of Internet of Things(IoT),a physical layer key generation method based on reception signal strength(RSS)and multichannel sampling is proposed by means of the channel fast switching ability of ZigBee sensor devices. With the help of the randomness of multipath time-varying channels,the multiple interval sampling for RSS on multi-communication sub-channels in2.4G frequency band is conducted based on channel selection strategy and detection protocol,and then the matrix caching,mean filtering and quantization for the sampled values are performed. The session key is obtained by means of key agreement protocol. In this method,multi-channel RSS is innovatively used as the characteristic information of key generation,which can effectively reduce the correlation between characteristic sampling values and the influence of channel coherence time on sampling speed,thus greatly improving the key generation rate and key consistency. The experimental results show that,in real indoor mobile environment,this method can achieve a key generation rate of more than 10 bit/s,and can effectively suppress malicious attacks. This method is simple,efficient,and easy to implement on IoT devices.