Touch-Based Magnetic Communication through Your Hand

Near field communication (NFC), which emerged only a decade ago, has been rapidly adopted in business services including point-of-sale (POS) systems, payments, identification, ticketing, and various other types of services. NFC offers great and varied promise in providing secure and implicit paired communication capability in smartphones. As a short-range wireless communication technology, the level of "secure" is contributed by the short-range nature. Compared with other competitive technologies, NFC achieves physical-level security but sacrifices convenience. For example, NFC cannot achieve device-free or hands-free payment transactions like the service provided by PayPal called PayPal beacon which utilizes Bluetooth-low-energy (BLE) technology. In this paper, we propose a low-cost wearable device that can achieve better physical-level security than NFC provides. This system is compatible with existing NFC-based POS systems and can help users realize a convenient hands-free payment transaction. Specifically, a custom NFC wristband was designed to channel its magnetic field through the human arm. By confining the magnetic field in NFC to the area around the body, we could minimize energy radiation, reduce the possibility of communication sniffing and hijackings, and improve security. To evaluate this approach, we conducted various experiments via different configurations. The results showed that the communication range for the human body channel was greater than that of the air and water channels. In addition, through this study we demonstrated that the human body is a naturally secure channel, and hacking and nearby interference are minimized during such communication. Our system also defines a new way of communication, for example, people can share confidential information with a simple handshake without pulling out and touching, or tapping smartphones.