Radio Frequency Identification

Radio Frequency Identification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is an object that can be attached to or incorporated into a product, animal, or person for the purpose of identification using radio waves. Chip-based RFID tags contain silicon chips and antennas. Passive tags require no internal power source, whereas active tags require a power source.History of RFID tags

An RFID tag used for electronic toll collection

In 1945 Léon Theremin invented an espionage tool for the Soviet government which retransmitted incident radio waves with audio information. Soundwaves vibrated a diaphragm which slightly altered the shape of the resonator, which modulated the reflected radio frequency. Even though this device was a passive covert listening device, not an identification tag, it has been attributed as the first known device and a predecessor to RFID technology. The technology used in RFID has been around since the early 1920s according to one source (although the same source states that RFID systems have been around just since the late 1960s) ^[1][2].

A more similar technology, the IFF transponder, was invented by the British in 1939 [1], and was routinely used by the allies in World War II to identify airplanes as friend or foe.

Another early work exploring RFID is the landmark 1948 paper by Harry Stockman, titled "Communication by Means of Reflected Power" (Proceedings of the IRE, pp 1196–1204, October 1948). Stockman predicted that "...considerable research and development work has to be done before the remaining basic problems in reflected-power communication are solved, and before the field of useful applications is explored."

Mario Cardullo claims that his U.S. Patent 3,713,148 in 1973 was the first true ancestor of modern RFID; a passive radio transponder with memory. [2] The first demonstration of today's reflected power (backscatter) RFID tags was done at the Los Alamos Scientific Laboratory in 1973. [3]

Types of RFID tags

RFID cards are also known as "proximity" or "proxy" cards and come in three general varieties: passive, semi-passive (also known as semi-active), or active.

Passive

Passive RFID tags have no internal power supply. The minute electrical current induced in the antenna by the incoming radio frequency signal provides just enough power for the CMOS integrated circuit (IC) in the tag to power up and transmit a response. Most passive tags signal by backscattering the carrier signal from the reader. This means that the aerial (antenna) has to be designed to both collect power from the incoming signal and also to transmit the outbound backscatter signal. The response of a passive RFID tag is not just an ID number (GUID); the tag chip can contain nonvolatile EEPROM for storing data. Lack of an onboard power supply means that the device can be quite small: commercially available products exist that can be embedded under the skin. As of 2006, the smallest such devices measured 0.15 mm × 0.15 mm, and are thinner than a sheet of paper (7.5 micrometers).[4] The lowest cost EPC RFID tags, which are standard chosen by Wal-Mart, DOD, Target, Tesco in the UK and Metro AG in Germany, are available today at a price of 5 cents each. The addition of the antenna creates a tag that varies from the size of a postage stamp to the size of a post card. Passive tags have practical read distances ranging from about 10 cm (4 in.) (ISO 14443) up to a few meters (EPC and ISO 18000-6) depending on the chosen radio frequency and antenna design/size. Due to their simplicity in design they are also suitable for manufacture with a printing process for the antennas. Passive RFID tags do not require batteries, can be much smaller, and have an unlimited life span. Non-silicon tags made from polymer semiconductors are currently being developed by several companies globally. Simple laboratory printed polymer tags operating at 13.56 MHz were demonstrated in 2005 by both PolyIC (Germany) and Philips (The Netherlands). If successfully commercialized, polymer tags will be roll printable, like a magazine, and much less expensive than silicon-based tags. The end game for most item level tagging over the next few decades is that RFID tags will be wholly printed - the same way a barcode is today - and be virtually free, like a barcode.

Semi-passive

Semi-passive RFID tags are very similar to passive tags except for the addition of a small battery. This battery allows the tag IC to be constantly powered, which removes the need for the aerial to be designed to collect power from the incoming signal. Aerials can therefore be optimized for the backscattering signal. Semi-passive RFID tags are thus faster in response, though less reliable and powerful than active tags. Semi-passive tags offer benefits in environments where there is a lot of metal or fluids, which typically scatter the RF field and can cause non-reads with passive tags. As semi-passive tags are pre-energized, they can be read more reliably in these more difficult environments.

Active

Unlike passive RFID tags, active RFID tags have their own internal power source which is used to power any ICs that generate the outgoing signal. Active tags are typically much more reliable (e.g. fewer errors) than passive tags due to the ability for active tags to conduct a "session" with a reader. Active tags, due to their onboard power supply, also transmit at higher power levels than passive tags, allowing them to be more effective in "RF challenged" environments like water (including humans/cattle, which are mostly water), metal (shipping containers, vehicles), or at longer distances. Many active tags have practical ranges of hundreds of meters, and a battery life of up to 10 years. Some active RFID tags include sensors such as temperature logging which have been used in concrete maturity monitoring or to monitor the temperature of perishable goods. Other sensors that have been married with active RFID include humidity, shock/vibration, light, radiation, temperature and atmospherics like ethylene. Active tags typically have much longer range (approximately 300 feet) and larger memories than passive tags, as well as the ability to store additional information sent by the transceiver. The United States Department of Defense has successfully used active tags to reduce logistics costs and improve supply chain visibility for more than 15 years. At present, the smallest active tags are about the size of a coin and sell for a few dollars.

The RFID system

An RFID system may consist of several components: tags, tag readers, edge servers, middleware, and application software.

The purpose of an RFID system is to enable data to be transmitted by a mobile device, called a tag, which is read by an RFID reader and processed according to the needs of a particular application. The data transmitted by the tag may provide identification or location information, or specifics about the product tagged, such as price, color, date of purchase, etc. The use of RFID in tracking and access applications first appeared in 1932, to identify aircraft as friendly or unfriendly ("identify friend or foe" (IFF). RFID quickly gained attention because of its ability to track moving objects. As the technology is refined, more pervasive and possibly invasive uses for RFID tags are in the works.

In a typical RFID system, individual objects are equipped with a small, inexpensive tag. The tag contains a transponder with a digital memory chip that is given a unique electronic product code. The interrogator, an antenna packaged with a transceiver and decoder, emits a signal activating the RFID tag so it can read and write data to it. When an RFID tag passes through the electromagnetic zone, it detects the reader's activation signal. 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).

Take the example of books in a library. Security gates can detect whether or not a book has been properly checked out of the library. When users return items, the security bit is re-set and the item record in the Integrated library system is automatically updated. In some RFID solutions, a return receipt can be generated. At this point, materials can be roughly sorted into bins by the return equipment. Inventory wands provide a finer detail of sorting. This tool can be used to put books into shelf-ready order.

Current usage

Transport payments

• The New York City Subway is conducting a trial during the second half of 2006, utilizing PayPass by MasterCard as fare payment.

• The Moscow Metro, the world's busiest, was the first system in Europe to introduce RFID smartcards in 1998.

• In the UK, systems for prepaying for unlimited public transport have been devised, making use of RFID technology. The design is embedded in a creditcard-like pass, that when scanned reveals details of whether the pass is valid, and for how long the pass will remain valid. The first company to implement this is the NCT company of Nottingham City, where the general public affectionately refer to them as "beep cards". It has since then been implemented with great success in London, where "Oyster cards" allow for pay-as-you-go travel as well as passes valid for various lengths of time and in various areas.

• In Hong Kong, mass transit is paid for almost exclusively paid for with the use of an RFID technology, called the Octopus Card. Originally it was launched in September 1997 exclusively for transit fare collection, but has grown to be similar to a cash card, and can be used in vending machines, fast-food restaurants and supermarkets. The card itself can be recharged with cash at add-value machines or over the counter in shops, and can be successfully read several centimetres from the reader.

• "Navigo" passes for the Paris public transport system (RATP) also use RFID technology.

• RFID tags are used for electronic toll collection at toll booths with Georgia's Cruise Card, California's FasTrak, Illinois' I-Pass, the expanding eastern states' E-ZPass system (including Massachusetts's Fast Lane), Florida's SunPass, North Texas NTTA and Houston HCTRA EZ Tag, The "Cross-Israel Highway" (Highway 6), Philippines South Luzon Expressway E-Pass, Brisbane's Queensland Motorway E-Toll System in Australia, Autopista del Sol (Sun's Highway), Autopista Central (Central Highway), Autopista Los Libertadores, Costanera Norte, Vespucio Norte Express and Vespucio Sur urban Highways and every forthcoming urban highway (in a "Free Flow" modality) concessioned to private investors in Chile and all highways in Portugal (Via Verde, the first system in the world to span the entire network of tolls) and France (Liber-T system). The tags, which are usually the active type, are read remotely as vehicles pass through the booths, and tag information is used to debit the toll from a prepaid account. The system helps to speed traffic through toll plazas as it records the date, time, and billing data for the RFID vehicle tag.

• A number of ski resorts, particularly in the French Alps, have adopted RFID tags to provide skiers hands-free access to ski lifts.

Product Tracking

• The Canadian Cattle Identification Agency began using RFID tags as a replacement for barcode tags. The tags are required to 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 currently developing its own program.

RFID tags used in libraries: square book tag, round CD/DVD tag and rectangular VHS tag.

• High-frequency RFID tags are used in library book or bookstore tracking, pallet tracking, building access control, airline baggage tracking, and apparel and pharmaceutical item tracking. High-frequency tags are widely used in identification badges, replacing earlier magnetic stripe cards. These badges need only be held within a certain distance of the reader to authenticate the holder. The American Express Blue credit card now includes a high-frequency RFID tag.

• UHF RFID tags are commonly used commercially in case, pallet, and shipping container tracking, and truck and trailer tracking in shipping yards.

Automotive

• Microwave RFID tags are used in long range access control for vehicles.

• Since the 1990's, RFIDs are used in the car keys, as theft protection. Without correct RFID the car will not start.

• In January 2003, Michelin began testing RFID transponders embedded into tires. After a testing period that is expected to last 18 months, the manufacturer will offer RFID-enabled tires to car makers. Their primary purpose is tire-tracking in compliance with the United States Transportation, Recall, Enhancement, Accountability and Documentation Act (TREAD Act).

• Starting with the 2004 model year, a Smart Key/Smart Start option became available to the Toyota Prius. Since then, Toyota has been introducing the feature on various models around the world under both the Toyota and Lexus brands, including the Toyota Avalon (2005 model year), Toyota Camry (2007 model year), and the Lexus GS (2006 model year). 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.

Other

• Sensors such as seismic sensors may be read using RFID transceivers, greatly simplifying remote data collection.

• Some smart cards embedded with RFID chips are used as electronic cash, e.g. SmarTrip in Washington, DC, USA, EasyCard in Taiwan, Suica in Japan, T-Money in South Korea, Octopus Card in Hong Kong, and the Netherlands and Oyster Card on the London Underground in the United Kingdom to pay fares in mass transit systems and/or retails. The Chicago Transit Authority recently began using RFID technology in their Chicago Card.

• In August 2004, the Ohio Department of Rehabilitation and Correction (ODRH) approved a $415,000 contract to evaluate the personnel tracking technology of Alanco Technologies. Inmates will wear wristwatch-sized transmitters that can detect if prisoners have been trying to remove them and send an alert to prison computers. This project is not the first such rollout of tracking chips in US prisons. Facilities in Michigan, California and Illinois already employ the technology.

RFID in inventory systems

An advanced automatic identification technology such as the Auto-ID system based on the Radio Frequency Identification (RFID) technology has two values for inventory systems. First, the visibility provided by this technology allows an accurate knowledge on the inventory level by eliminating the discrepancy between inventory record and physical inventory. Second, the RFID technology can prevent or reduce the sources of errors. Benefits of using RFID include the reduction of labour costs, the simplification of business processes and the reduction of inventory inaccuracies.

RFID mandates

Wal-Mart and the United States Department of Defense have published requirements that their vendors place RFID tags on all shipments to improve supply chain management [5]. Due to the size of these two organizations, their RFID mandates impact thousands of companies worldwide. The deadlines have been extended several times because many vendors face significant difficulties implementing RFID systems. In practice, the successful read rates currently run only 80%, due to radio wave attenuation caused by the products and packaging. In time it is expected that even small companies will be able to place RFID tags on their outbound shipments.

Since January, 2005, Wal-Mart has required its top 100 suppliers to apply RFID labels to all shipments. To meet this requirement, vendors use RFID printer/encoders to label cases and pallets that require EPC tags for Wal-Mart. These smart labels are produced by embedding RFID inlays inside the label material, and then printing bar code and other visible information on the surface of the label.

Human implants

Hand with the planned location of the RFID chip

Just after the operation to insert the RFID tag was completed

Implantable RFID chips designed for animal tagging are now being used in humans. An early experiment with RFID implants was conducted by British professor of cybernetics Kevin Warwick, who implanted a chip in his arm in 1998. Night clubs in Barcelona, Spain and in Rotterdam, The Netherlands, use an implantable chip to identify their VIP customers, who in turn use it to pay for drinks [6].

In 2004, the Mexican Attorney General's office implanted 18 of its staff members with the Verichip to control access to a secure data room. (This number has been variously mis-reported as 160 or 180 staff members, though the correct number is actually 18. [7])

Many books published about RFID are aimed at medium to large businesses implimenting RFID technology to track shipments or livestock; however, until the publication of RFID Toys [8] by Amal Graafstra in 2006 little information was available for the enthusiast. Shortly after the book's publication, the Seattle Center On Contemporary Art [9] hosted a live implant proceedure proformed on Phillip Beynon, a student from Vancouver Canada.

Security experts are warning against using RFID for authenticating people due to the risk of Identity Theft. For instance a Mafia Fraud Attack would make it possible for an attacker to steal the identity of a person in real-time. Due to the resource-constraints of RFIDs it is virtually impossible to protect against such attack models as this would require complex distance-binding protocols.

Fingerprint

A fingerprint is an impression normally made by ink or contaminants transferred from the peaks of friction skin ridges to a relatively smooth surface such as a fingerprint card. These ridges are sometimes known as "dermal ridges" or "dermal papillae". The term fingerprint normally refers to impressions transferred from the pad on the last joint of fingers and thumbs, though fingerprint cards also typically record portions of lower joint areas of the fingers (which are also used to effect identifications). Friction skin ridges are not unique to humans, however, and some species of primate also have friction skin ridges on "fingers" and paws in configurations sometimes similar to human friction ridge skin. Some New World monkeys also have friction ridge skin on their tails, possibly associated with use of their tails for gripping during climbing, and the knuckle-walking great apes have friction ridge skin on the dorsal surfaces of their fingers. Friction skin ridges on humans are commonly believed to provide traction for grasping objects. In the over 100 years that fingerprints have been examined and compared, no two areas of friction ridge skin on any two fingers or palms (including between identical twins) have been found to have the same friction ridge characteristics.

Fingerprint identification

Fingerprint identification (sometimes referred to as dactyloscopy) is the process of comparing questioned and known friction skin ridge impressions (see Minutiae) from fingers, palms, and toes to determine if the impressions are from the same finger (or palm, toe, etc.). The flexibility of friction ridge skin means that no two finger or palm prints are ever exactly alike (never identical in every detail), even two impressions recorded immediately after each other. Fingerprint identification (also referred to as individualization) occurs when an expert (or an expert computer system operating under threshold scoring rules) determines that two friction ridge impressions originated from the same finger or palm (or toe, sole) to the exclusion of all others.

Latent prints

Although the word latent means hidden or invisible, in modern usage for forensic science the term latent prints means any chance or accidental impression left by friction ridge skin on a surface, regardless of whether it is visible or invisible at the time of deposition. Electronic, chemical and physical processing techniques permit visualization of invisible latent print residue whether it is from natural secretions of the eccrine glands present on friction ridge skin (which produce palmar sweat, but no oils), or whether the impression is in a contaminate such as oil, blood, paint, ink, etc.

Patent prints

These are prints which are obvious to the human eye and are caused by a transfer of foreign material on the finger, onto a surface. Because they are already visible they need no enhancement, and are photographed instead of being lifted. Where possible, the item containing the print is taken away and looked at by forensic scientists.

Plastic prints

A plastic print is a friction ridge impression from a finger or palm (or toe/foot) deposited in a material that retains the shape of the ridge detail. Commonly encountered examples are melted candle wax, putty removed from the perimeter of window panes and thick grease deposits on car parts. Such prints are already visible and need no enhancement, but investigators must not overlook the potential that invisible latent prints deposited by accomplices may also be on such surfaces. After photographically recording such prints, attempts should be made to visualize other non-plastic impressions deposited in natural finger/palm secretions (eccrine gland secretions) or contaminates.

Classifying fingerprints

There are three basic fingerprint patterns: Arch, Loop and Whorl. There are also more complex classification systems that further break down patterns to plain arches or tented arches. Loops may be radial or ulnar, depending on the side of the hand the tail points towards. Whorls also have sub-group classifications including plain whorls, accidental whorls, double loop whorls, and central pocket loop whorls.

Arch

Right loop

Whorl

Tented arch