As wireless networks move to millimetre-wave (mm-wave) and terahertz (THz) frequencies for 5G communications and beyond, ensuring security and resilience to eavesdropper attacks has become increasingly important. Traditional encryption methods are challenging to scale for high-bandwidth, ultralow-latency applications. An alternative approach is to use physical-layer techniques that rely on the physics of signal propagation to incorporate security features without the need for an explicit key exchange. Ensuring security through the use of directional, narrow-beam-like features of mm-wave/THz signals has proven to be vulnerable to passive eavesdroppers. Here we report a space-time modulation approach that ensures security by enforcing loss of information through selective spectral aliasing towards the direction of eavesdroppers, even though the channel can be physically static. This is achieved by using custom-designed spatio-temporal transmitter arrays realized in silicon chips with packaged antennas operating in the 71–76 GHz range. We also analytically and experimentally demonstrate the resilience of our links against distributed and synchronized eavesdropper attacks in the mm-wave band.

随着无线网络转向毫米波 (mm-wave) 和太赫兹 (THz) 频率用于 5G 通信及更高频率，确保安全性和抵御窃听者攻击的能力变得越来越重要。传统的加密方法很难扩展到高带宽、超低延迟的应用程序。另一种方法是使用依赖于信号传播物理特性的物理层技术来整合安全特性，而不需要显式的密钥交换。事实证明，通过使用毫米波/太赫兹信号的定向窄波束特性来确保安全性很容易受到被动窃听者的攻击。在这里，我们报告了一种时空调制方法，该方法通过选择性频谱混叠向窃听者的方向强制信息丢失来确保安全性，即使通道可以是物理静态的。这是通过使用在硅芯片中实现的定制设计的时空发射器阵列以及在 71-76 GHz 范围内工作的封装天线来实现的。我们还通过分析和实验证明了我们的链接对毫米波段中分布式和同步窃听者攻击的弹性。