Secret-key generation and agreement based on wireless channel reciprocity offers a promising avenue for securing IoT networks. However, existing approaches predominantly rely on the similarity of instantaneous channel measurement samples between communicating devices. This narrow view of reciprocity is often impractical, as it is highly susceptible to noise, asynchronous sampling, channel fading, and other system-level imperfections -- all of which significantly impair key generation performance. Furthermore, the quantization step common in traditional schemes introduces irreversible errors, further limiting efficiency. In this work, we propose a novel approach for secret-key generation by using wavelet scattering networks to extract robust and reciprocal CSI features. Dimensionality reduction is applied to uncover hidden cluster structures, which are then used to build hidden Markov models for efficient key agreement. Our approach eliminates the need for quantization and effectively captures channel randomness. It achieves a 5x improvement in key generation rate compared to traditional benchmarks, providing a secure and efficient solution for key generation in resource-constrained IoT environments.

翻译：基于无线信道互易性的密钥生成与协商为保障物联网网络安全提供了一条前景广阔的途径。然而，现有方法主要依赖于通信设备间瞬时信道测量样本的相似性。这种对互易性的狭义理解往往不切实际，因为它极易受到噪声、异步采样、信道衰落以及其他系统级缺陷的影响——所有这些都会显著损害密钥生成性能。此外，传统方案中常见的量化步骤会引入不可逆的误差，进一步限制了效率。在本工作中，我们提出了一种新颖的密钥生成方法，利用小波散射网络提取鲁棒且具有互易性的信道状态信息特征。通过应用降维技术揭示隐藏的聚类结构，进而构建隐马尔可夫模型以实现高效的密钥协商。我们的方法无需量化步骤，并能有效捕捉信道随机性。与传统基准方法相比，该方法将密钥生成速率提升了五倍，为资源受限的物联网环境中的密钥生成提供了一种安全高效的解决方案。