Towards Location- and Orientation-Independent RFID Authentication with COTS Devices

To authenticate tags against counterfeiting, RF fin-gerprinting technique is widely exploited. However, the status of tagged item is always changed by movement, rotation and other operations. When the item's location or orientation changes, the capability of past methods would be severely affected and their supported authentication ranges are fairly small. To overcome this challenge, we propose the first-of-its-kind method FreeAuth to achieve certain location- and orientation-independent RFID authentication without any customized devices, by attaching a tag-pair and hopping the frequency channels and transmission powers. The key insight of FreeAuth lies in an implicit fin-gerprint matching scheme where the distance-frequency-power and orientation-frequency-power relationships are leveraged to circumvent these two negative factors. We implement a prototype of FreeAuth with COTS devices and the experiments demonstrate that FreeAuth is able to achieve around 0.8m and 0.6m ranges along 2D axes, in which the authentication accuracy is over 80%. The average effective authentication range of FreeAuth can outperform the state-of-the-art method by 11.67 x.