The proliferation of massive Internet of Things (IoT) devices poses research challenges especially in unmanned aerial vehicles(UAV)-assisted IoT. In particular, the limited battery capacity not only restricts the life time of UAV-assisted IoT but also brings security vulnerabilities since computation-complex cryptographic algorithms cannot be adopted in UAV-assisted IoT systems. In this paper, artificial noise and wireless power transfer technologies are integrated to secure communications in UAV-assisted IoT (particularly in secret key distribution). We present the artificial noise aided scheme to secure UAV-assisted IoT communications by letting UAV gateway transfer energy to a number of helpers who will generate artificial noise to interfere with the eavesdroppers while the legitimate nodes can decode the information by canceling additive artificial noise. We introduce the eavesdropping probability and the security rate to validate the effectiveness of our proposed scheme. We further formulate an eavesdropping probability constrained security rate maximization problem to investigate the optimal power allocation. Moreover, analytical and numerical results are provided to obtain some useful insights, and to demonstrate the effect of crucial parameters (e.g., the transmit power, the main channel gain) on the eavesdropping probability, the security rate, and the optimal power allocation.

大规模物联网（IoT）设备的激增带来了研究挑战，尤其是在无人机（UAV）辅助的IoT中。特别地，有限的电池容量不仅限制了无人机辅助物联网的使用寿命，而且由于安全隐患无法在无人机辅助物联网系统中采用，因此带来了安全漏洞。本文将人工噪声和无线电力传输技术集成在一起，以确保无人机辅助物联网（尤其是密钥分发）中的通信安全。我们提出了一种人工噪音辅助方案，通过让无人机网关将能量转移给许多助手，这些辅助助手将产生人工噪声来干扰窃听者，而合法节点可以通过消除附加人工噪声来解码信息，从而确保无人机辅助物联网通信的安全。我们介绍了窃听概率和安全率，以验证所提出方案的有效性。我们进一步提出了一种监听概率受限的安全率最大化问题，以研究最优功率分配。此外，提供分析和数值结果以获得一些有用的见解，并证明关键参数（例如，发射功率，主信道增益）对窃听概率，安全率和最佳功率分配的影响。