An Approach to Near Field Data Selection in Radio Frequency Identification

Robert D Winkworth, Purdue University


Personal identification is needed in many civil activities, and the common identification cards, such as a driver's license, have become the standard document de facto. Radio frequency identification has complicated this matter. Unlike their printed predecessors, contemporary RFID cards lack a practical way for users to control access to their individual fields of data. This leaves them more available to unauthorized parties, and more prone to abuse. Here, then was undertaken a means to test a novel RFID card technology that allows overlays to be used for reliable, reversible data access settings. Similar to other proposed switching mechanisms, it offers advantages that may greatly improve outcomes. RFID use is increasing in identity documents such as drivers' licenses and passports, and with it concern over the theft of personal information, which can enable unauthorized tracking or fraud. Effort put into designing a strong foundation technology now may allow for widespread development on them later. In this dissertation, such a technology was designed and constructed, to drive the central thesis that selective detuning could serve as a feasible, reliable mechanism. The concept had been illustrated effective in limiting access to all fields simultaneously before, and was here effective in limiting access to specific fields selectively. A novel card was produced in familiar dimensions, with an intuitive interface by which users may conceal the visible print of the card to conceal the wireless emissions it allows. A discussion was included of similar technologies, involving capacitive switching, that could further improve the outcomes if such a product were put to large-scale commercial fabrication. The card prototype was put to a battery of laboratory tests to measure the degree of independence between data fields and the reliability of the switching mechanism when used under realistically variable coverage, demonstrating statistically consistent performance in both. The success rate of RFID card read operations, which are already greater than 99.9%, were exceeded by the success rate of selection using the featured technology. With controls in place for the most influential factors related to card readability (namely the distance from the reader antennas and the orientation of the card antenna with respect to them), the card was shown to completely resist data acquisition from unauthorized fields while allowing unimpeded access to authorized fields, even after thousands of varied attempts. The effect was proven to be temporary and reversible. User intervention allowed for the switching to occur in a matter of seconds by sliding a conductive sleeve or applying tape to regions of the card. Strategies for widespread implementation were discussed, emphasizing factors that included cost, durability, size, simplicity, and familiarity, all of which arise in card management decisions for common state and national identification such as a driver's license. The relationship between the card and external database systems was detailed, as no such identification document could function in isolation. A practical solution involving it will include details of how multiple fields will be written to the card and separated sufficiently in external databases so as to allow for user-directed selection of data field disclosure. Opportunities for implementation in corporate and academic environments were discussed, along with the ways in which this technology could invite further investigation.




Dyrenfurth, Purdue University.

Subject Area

Engineering|Electromagnetics|Computer science

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