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RFID - An Overview

RFID has been around since the 1980's for tracking applications, though it was beyond most budgets for real world business applications at that time.. It is only recently that RFID has hit the main stream as a viable asset tracking tool for business. Most of the push into the main stream can be traced to Wal-Mart and the U.S. Department of Defense, which have both published mandates requiring their vendors to place RFID tags on all shipments. The main reason given is to improve supply chain management. Because of the size of these two organizations the mandates of course affect thousands of companies worldwide.

Since that time (Wal-Mart began requiring its top 100 suppliers to apply RFID labels in January of 2005), RFID systems have come into the light with many vendors seeking better and less expensive methods of applying them to outgoing shipments, as well as using the technology for internal asset tracking.

An RFID system requires equipment to have an inexpensive tag placed on it, which is very similar to a barcode tag. The inexpensive types are called Passive RFID tags, and today cost somewhere in the lines of .50 a piece. In the next few years this cost is expected to drop down to around .05 a piece (these values are in US Dollars). A Passive RFID tag has no power of its own, it is essentially a very small processor surrounded by a long antennal which is woven through the tag. The signal from the RFID reader transmits enough power to bring the processor to life and for it to transmit a short signal. This is typically just an ID number, requiring the database for matching the number up on the reader end to gain more information. The reader decodes the data encoded in the tag's integrated circuit (silicon chip) and the data is passed to the host computer. The application software on the host processes the data, often employing Physical Markup Language (PML).

RFID applications are all around us today and becoming more common place. The Department of Veterans Affairs Outpatient pharmacies, for example, now supply tags which store label information for prescriptions. A battery powered "reader" placed next to the prescription reads and then speaks information about the prescription, such as : the drug name, instructions and any warnings regarding the medicine contained inside the bottle.
http://www.envisionamerica.com/scriptalk.htm

The Canadian Cattle Identification Agency began using RFID tags as a replacement for barcode tags. The tags identify a bovine's herd of origin and this is used for trace-back when a packing plant condemns a carcass. Currently CCIA tags are used in Wisconsin and by US farmers on a voluntary basis. The USDA is developing its own program. Some European nations are looking into programs of their own as well.

Starting with the 2004 model year, a Smart Key/Smart Start option became available to the Toyota Prius. Since then, Toyota has been adding the feature to various models under both the Toyota and Lexus brands. The key uses an active RFID circuit which allows the car to acknowledge the key's presence within approximately 3 feet of the sensor. The driver can open the doors and start the car while the key remains in a purse or pocket.

A primary security concern surrounding RFID technology is the illicit tracking of RFID tags. Tags which are world-readable pose a risk to both personal location privacy and corporate/military security. Such concerns have been raised with respect to the United States Department of Defense's recent adoption of RFID tags for supply chain management.

A second class of defense uses cryptography to prevent tag cloning. Some tags use a form of "rolling code" scheme, where the tag identifier information changes after each scan. More sophisticated devices engage in challenge-response protocols where the tag interacts with the reader. In these protocols, secret tag information is never sent over the insecure communication channel between tag and reader. Rather, the reader issues a challenge to the tag, which responds with a result computed using a cryptographic circuit keyed with some secret value. Such protocols may be based on symmetric or public key cryptography. Cryptographically-enabled tags typically have dramatically higher cost and power requirements than simpler equivalents, and as a result, deployment of these tags is much more limited.

This cost/power limitation has led some manufacturers to implement cryptographic tags using substantially weakened, or proprietary encryption schemes, which do not necessarily resist sophisticated attack. For example, the Exxon-Mobil Speedpass uses a cryptographically-enabled tag manufactured by Texas Instruments, called the Digital Signature Transponder (DST), which incorporates a weak, proprietary encryption scheme to perform a challenge-response protocol. In 2005, researchers from RSA Labs and Johns Hopkins University reverse engineered the algorithm and were able to clone Speedpass tags http://www.rfidanalysis.org