Secure Inductive-Coupled Near Field Communication at Physical Layer

Near field communication (NFC) is widely used today in many useful applications, such as contactless payment, identification, and file exchange. Due to the limitations on computation, power, and cost of NFC devices, NFC systems often lack encryption or are weakly encrypted, leaving them exposed to security attacks. One solution for this problem is to install strong cryptographic protocols on NFC devices. However, it involves upgrading and revoking deployed NFC devices, which is costly and impractical. Moreover, encryption algorithms are usually considered expensive for resource constrained NFC devices in terms of computation overhead and energy consumption. Aiming at a solution to tackle the security threat without revoking or changing the insecure NFC devices, this paper investigates whether the recent advance of physical layer security can be applied as a means to secure NFC. A detailed analysis is performed to reveal two unique challenges brought by NFC's data transmission mechanism. A practical solution, SecNFC, through special waveform design at the initiator is proposed. Extensive simulations and concept-proof experiments are conducted to evaluate the performance of our solution. Both simulation and experimental results show that SecNFC can efficiently prevent NFC from eavesdropping with a slight and tolerable decoding performance degradation at the initiator.