UW Society and Technology Group RFID Position Paper

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The debate surrounding RFID is one that hits close to home for UW students. The CSE building is currently going through a large scale RFID deployment, foreshadowing what is to come in shops, offices, homes, and cities. In this whitepaper, we explore the broader practical, legal and sociopolitical implications of the technology.

RFID overview

Radio Frequency IDentification (RFID) is a technology that utilizes radio signals to automatically identify unique objects. RFID's first real use was during WWII when Britain and the Allies used RFID to distinguish friendly planes from enemy planes. The costs of the technology, however, have kept RFID out of mass deployment; it is only in the recent past that RFID has become feasible to deploy en masse.

The purpose of an RFID system is to enable data to be transmitted by a tag, which is read by an RFID reader and processed according to the needs of a particular application. Tags are attached to individual items that are to be tracked and contain a small amount of information about the object (usually a unique identification number). When an RFID tag passes through the reader's electromagnetic zone, it detects the reader's activation signal and transmits the information it contains. The reader decodes the data encoded in the tag and the data is passed to the host computer. The data is usually compared against a database. The database may provide information about the item to an application running on the same device as the reader (e.g. a reader on a cell phone that gives detailed information about an item about to be purchased). The data may also simply be recorded in the database (e.g. recording that a person wearing a tag just passed through a doorway where an active reader resided). These databases may be data-mined for many purposes; for example, in monitoring applications that track whether activities of daily living (ADLs) are being performed by elderly citizens who have outfitted their home with such an RFID system.


An RFID tag is an object that can be attached to or incorporated into an object for identification using radio waves. A tag usually has a chip and an antenna. There are two types of tags: active and passive.

Active tags have their own internal supply. They tend to more reliable, transmit more power, and are better for metal/liquid/distance (300ft) situations. Active tags have larger memories and can often store more information. They are about the size of a coin, sell for few dollars, and last a couple of years.

Passive tags are more common. They use the power from the reader to power up. They then respond with some information (sometimes just an ID). They are lower cost, shorter read range, and battery use is not a concern. They can be really tiny and thinner than a sheet of paper and sell for about 5 cents.


A reader interrogates the tag with a radio signal and the tag sends back the information stored on it. Technically speaking, a reader uses an antenna(s), transceiver and decoder to interrogate the tag.

Readers have different ranges and operate at different frequencies. The range is anywhere from a few centimeters to hundreds of meters. The read range depends on:

  • the frequency at which the communications take place
  • the orientation of the tags (hard to read a tag behind an object)
  • the material the tag is on (hard to read a tag placed on a metal surface or under water)
  • the number of co-located tags (hard to distinguish which tags are generating which radio signals)
  • the number of antenna in the reader (more antennas, greater range)

The readers used in CSE's RFID Ecosystem can read from about 30 ft away.


  • Authentication
  • keyless entry
  • passports
  • cars
  • Payment
  • E-Z Pass
  • Oyster cards
  • Tracking
  • Seattle library
  • pets
  • livestock
  • prescriptions and medicine doses in the hospital
  • activities of daily living for the elderly
  • Other
  • e-cash
  • museums
  • race timing

Technical questions and answers

  • Tag technology
  • What kinds of data is it feasible to store on tags?
  • Is it possible for tags to transmit information only to authenticated readers? How cost prohibitive would that be?
  • Reader technology
  • What kinds of material can readers read tags through? Are there materials that readers cannot (and will not) be able to eventually read through?
  • What are the prospects of readers being able to filter noise created by co-located tags?
  • Database technology
  • What constraints does storage impose on the collection and archiving of such fine-grained data?
  • Can data be scrubbed in order to filter out personal information in such a way that privacy is preserved?
  • Activity recognition
  • What kinds of activities can be inferred by tagged items? How good are existing techniques?

Legal questions and answers

  • Do existing fair information practice laws help to inform RFID privacy issues?
  • Is RFID qualitatively different from other technologies that aggregate massive amounts of data?
  • In consumer applications (i.e. clothing) are warning labels. The Gap sells pants with tags that read "REMOVE BEFORE WASHING OR WEARING". This warning does not disclose the potential danger in not removing the tag.
  • Are tradeoffs between privacy and convenience necessary?
  • In what cases?
  • Are there policies that can be adopted that minimize the magnitude of the tradeoffs?

Sociopolitical questions and answers

  • In what ways can RFID serve to centralize control over individuals?
  • Which elements of society will be in control of RFID deployments? Who will have access to the databases of information?
  • Is it likely that the availability of such fine-grained information will transform underlying power relations?
  • How could labor relations change if RFID is deployed extensively in the workplace? What types of workers will be most likely to be affected and in what ways? How would such systems influence labor relations between unions and employers?
  • In what ways have powerful institutions shaped the deployment of RFID systems?

Economic questions and answers

  • Are we going to be seeing a mass production of tags that will drop their prices even more?
  • Will active tag technology ever reach mass production, or will it always be too cost prohibitive in comparison to passive tags?