Implementable Privacy for RFID Systems

Radio Frequency Identification (RFID) technology bridges the physical and virtual worlds by enabling computers to track the movement of objects. Within a few years, RFID tags will replace barcodes on consumer items to increase the efficiency in logistics processes. The same tags, however, can be used to monitor business processes of competitors and to track individuals by the items they carry or wear. This work seeks to diminish this loss of privacy by adding affordable privacy protection to RFID systems. Technical privacy measures should be integrated in RFID tags in order to thwart rogue scanning and preserve the privacy of individuals and corporations. To be available for the upcoming deployment of item-level tags, protection measures must not substantially increase the costs of RFID systems. Previously proposed solutions, however, would unacceptably increase the costs of RFID tags, because the solutions use building blocks which were not optimized for privacy applications. Privacy, therefore, has been considered too expensive to be included in low-cost tags. This dissertation instead argues that privacy can be achieved at very low cost within the tight constraints of the smallest RFID tags and the largest installations. Designing more economical protection systems requires a better understanding of what properties are crucial for privacy. By modeling the incentives of attackers and measuring the extent to which different protection measures rescind these incentives, protection systems can be found that prevent different attacks. Sufficient protection is achieved if the cost of rogue scanning exceeds its expected return for all likely attackers. Perfect protection is neither possible nor necessary to achieve strong privacy. Protection can be realized through the combination of purposefully designed cryptographic