We provide the first solution to an important question, “how a physical-layer authentication method can defend against signal replay attacks”. It was believed that if an attacker can replay the exact same reply signal of a legitimate authentication object (such as an RFID tag), any physical-layer authentication method will fail. This paper presents Hu-Fu, the first physical layer RFID authentication protocol that is resilient to the major attacks including tag counterfeiting, signal replay, signal compensation, and brute-force feature reply. Hu-Fu is built on two fundamental ideas, namely inductive coupling of two tags and signal randomization. Hu-Fu does not require any hardware or protocol modification on COTS passive tags and can be implemented with COTS devices. We implement a prototype of Hu-Fu and demonstrate that it is accurate and robust to device diversity and environmental changes, including locations, distance, and temperature. Hu-Fu provides a new direction of battery-free/low-power device authentication that enables numerous IoT applications.

中文翻译：

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胡福：重放弹性RFID身份验证

我们为一个重要的问题提供了第一个解决方案，即“物理层身份验证方法如何防御信号重放攻击”。人们认为，如果攻击者可以重放合法身份验证对象（例如RFID标签）的完全相同的答复信号，则任何物理层身份验证方法都将失败。本文介绍了Hu-Fu，这是第一个物理层RFID身份验证协议，可对包括标签伪造，信号重播，信号补偿和蛮力特征回复在内的主要攻击具有弹性。Hu-Fu建立在两个基本思想的基础上，即两个标签的电感耦合和信号随机化。Hu-Fu不需要对COTS无源标签进行任何硬件或协议的修改，并且可以与COTS设备一起实现。我们实现了Hu-Fu的原型，并演示了它对于设备多样性和环境变化（包括位置，距离和温度）的准确性和鲁棒性。Hu-Fu提供了无电池/低功率设备认证的新方向，可实现众多物联网应用。