Ultra high frequency radio frequency identification (UHF RFID) is becoming a key technology in the Internet of Things. It allows the implementation of batteryless and wireless nodes, including sensors and actuators. Due to its possible transmission range of >10 m and potential to carry critical information, security is a highly important topic. For this reason, the International Organization for Standardization has published several crypto suites for UHF RFID within the ISO-29167 standard in 2014. Recently, research has focused on implementing those encryption features on the transponder side. However, currently no crypto enabled UHF RFID readers are available. In order to cope with the rapid development in this field, 'open' and flexible readers based on software defined radios are needed. They make it possible to quickly adapt the protocol and to test new functionalities such as encryption. This paper deals with the first implementation of the ISO 29167-19 standardized RAMON decryption on a software defined radio. The programming of this hardware is done in LabVIEW which allows for controlling the built-in transceiver modules. However, first measurements show that the decryption takes 51 s. This is because LabVIEW is not suitable for handling very large numbers like they are utilized in cryptography. Because such a long processing time is not feasible in experiments nor in a real-life scenarios, this method is not suitable for a prototyping platform. Thus, a different approach is chosen to optimize the decryption processing time. LabVIEW still provides the framework for handling the protocol and controlling the transceivers, but the decryption is performed in a Java application. In that way, the entire decryption process takes only about 2.2 ms, which is 23,318 times faster than the implementation in LabVIEW. Thus, this new approach meets the necessary timing requirements and is suitable for realistic application scenarios. The shown method allows development and testing of new functionalities in UHF RFID systems but may also be employed in any application that require long processing times in LabVIEW. Furthermore, the implementation of decryption features is the first necessary step towards a fully compliant, crypto enabled interrogator for UHF RFID, featuring a high adaptability.
Keywords: UHF communication; cryptography; data security; radio frequency identification; software defined radio.