Enhancing Privacy for Passive UHF RFID using an SDR-based Reactive Jammer

Nowadays, passive Ultra High Frequency (UHF) Radio Frequency IDentification (RFID) is used ubiquitously in supply-chain management, logistics, and industrial environments. Both, the tags identifier and user memory may contain sensitive information, raising privacy concerns if read without authorization. To address this issue, security related amendments to the conventional standards have been made. Many of these extensions remain optional to ensure compatibility with older, insecure tags still in use. Due to supplementary costs, even new tags do not necessarily provide the needed capabilities to support cryptographic features. In prior work, various approaches using external devices have been proposed to protect such tags and have proven to be effective, either for High Frequency (HF) or UHF tags. These rely either on artificially created tag reply collisions or on the emission of consecutive, interfering commands to suppress the inventory process. In this paper, we propose a reactive approach to block unauthorized access by artificial, short term interference with reader commands. As an additional benefit, our proposal results in shorter channel allocation times compared to previous approaches. Furthermore, we recap previous suggestions from a UHF perspective.