FROM RFID TO SMART DUST

Over the past few years, a great deal has been written about "radio frequency ID tags" or RFID tags. Initially, the message was "They're coming, and they'll be very useful." Then it was, "They're here, but they're big and clunky and expensive. But soon they'll be small enough to hide under a product label and they will cost only pennies."

The alarmists did not hesitate to express concern about the negative effect on privacy, but before we get into that, we should consider just what an RFID tag is.

The basic idea is rooted in the physics of antennae. When a radio or TV signal hits an antenna, some of the energy in the electromagnetic wave that is the signal transfers to the antenna. In a radio or TV, this energy becomes an electrical current that is amplified to modulate a speaker and/or picture tube. The same basic process is what is going on with a wireless computer connection.

An RFID tag is a small computer chip with a tiny antenna built in. When a radio signal hits the antenna, an electrical current is generated. That current then powers the chip to do whatever it is designed to do. In an RFID tag, the chip reads information in the radio signal, and if that information says the signal comes from an authorized source, the chip then generates a signal of its own, carrying information such as an identification number. Since the signal is quite weak, it can be detected only by nearby detectors, or by very sensitive and somewhat further away detectors. Bigger chips, with bigger antennae, amd sometimes with batteries, can generate stronger signals. Bigger chips can also carry more information than just an ID number.

So what are they good for? The early (large, expensive) RFID tags were fastened to cargo containers and pallets of goods. When queried by a suitable radio signal, they could report ID numbers (corresponding, perhaps, to invoice numbers), origin, and destination. They are the heart of highway automatic toll systems (Transpass and E-ZPass). Customers of some gasoline companies can wave a gadget at the pump that automatically debits their account. I have a bank debit card that works similarly in some stores. Similar devices form the heart of systems you can buy now to track stolen cars. People in the field are now talking of including sensors for temperature that would enable a chip to report whether a food shipment was likely to be spoiled.

Current tiny tags can be used to replace bar codes on labels. Instead of using a laser scanner, a
cashier would activate a radio signal that induced everything in a shopping cart to report its identity and price. Checkout could be greatly speeded up. Taking inventory would become an easy task. So would logging new shipments into a warehouse. And such gains promise considerable cost savings for businesses. But businesses that have proposed using them in that way have met public objections. So far Wal-Mart (for instance) is restricting their use to inventory and keeping them away from the checkout stand; in "Wal-Mart Turns to Smart Tags," the Associated Press (Wired News, Friday, April 30, 2004) reported that for Wal-Mart,

"The radio frequency information, or RFID, tags provide automatic tracking of pallets and cases of goods. Eight suppliers are participating, using 21 products to be tracked. Wal-Mart said Thursday that it will have more than 100 suppliers using the tags by January. ... In a backshop retail environment, the tags will contain the details of what is in a case or on a pallet of goods. Rather than have a worker with a handheld scanner logging in barcodes, the system will let a computer system use a radio signal to log the goods as they arrive at the loading dock.

"The tags can also be used in the manufacturing process, which Dillman said can help suppliers become more efficient, and the tags will help companies on both ends know where their products are at all times.

"Wal-Mart says the tags will help reduce theft and counterfeiting, the latter particularly affecting prescription medicines.

"Dave Hogan, chief information officer for the National Retail Federation, said the RFID tags could gain an important place rather quickly. He said barcodes will likely be around for quite a while and that he expects them to be used in concert with RFID tags even when the new technology moves to store shelves."

In August 2006, Wal-Mart's new CIO, Rollin Ford, said that though less than 10% of their 6600+ worldwide stores are RFID-equipped, they do plan to continue with their RFID rollout.

Other current uses include inserting them under the skin to track livestock and identify lost pets. ID tags are even being sold for people; the idea is to track lost or kidnapped kids or record medical history
data in a way that cannot be lost (as can a medical alert bracelet).

To a technophile, this all sounds rather nice. It's a gadget with a host of beneficial uses. But there is enough resistance to keep commercial applications largely restricted to the supply chain. This resistance is based on the potential for someone with a reader to read the contents of your cupboards from outside your house. Such data could be used in many ways, not all of which would make us happy. The idea of embedded personal ID tags also alarms people, for--quite aside from concern over such things as national ID cards--such tags might enable moment-by-moment tracking (as discussed in the unit on Surveillance--see "Whereware"). This is already becoming a feature of cell phones, but at least one can leave a cell phone home. Concern over such things prompted Simson Garfinkel, writing in the October 2002 Technology Review, to propose an RFID Bill of Rights, saying that

"Consumers should have

• The right to know whether products contain RFID tags.
  
• The right to have RFID tags removed or deactivated when they purchase products.
  
• The right to use RFID-enabled services without RFID tags.
  
• The right to access an RFID tag’s stored data.
  
• The right to know when, where and why the tags are being read.
  

"I see these not necessarily as the basis for new law, but as a framework for voluntary guidelines that companies wishing to deploy this technology can publicly adopt. Consumers could then boycott companies that violate these principles.

"Of course, some of these 'rights' could easily be curbed or otherwise limited by federal regulation. For example, the U.S. Department of Transportation could require certain safety-critical parts inside a car to have radio tags to aid in recalls. But for the overwhelming majority of applications, these rights make sense. Manufacturers have no business playing hide-and-seek with radio tags when consumer privacy is at issue. Likewise, they shouldn’t be able to require that consumers choose between participating in tomorrow’s economy and preserving their privacy. For example, this spring [2002] the Massachusetts Turnpike Authority started giving discounts to state residents who pay tolls with electronic transponders—a policy that is both discriminatory and coercive."

I can easily imagine a device for sale to consumers that would detect and destroy RFID tags attached to products. But even if such a thing never shows up in stores, I suspect it is only a matter of time before RFID tags are as ubiquitous as bar codes. It is also only a matter of time before RFID tags start getting hacked.

As we noted earlier, technologies can fail to emerge because they are supplanted by better alternatives. On July 17, 2006, Hewlett Packard announced a new chip the size of a tomato seed. "The Memory Spot has a 10 megabits-per-second data-transfer rate and can store up to 4 megabits of data." Reading it requires physical contact, so no more scan-from-a-distance privacy issues. Because it contains so much more memory, new applications become possible, such as attaching sound clips to the pictures in a (hardcopy) family album. HP says it may hit the market in two to five years.

This seems something to keep an eye on. Will it replace RFID? Perhaps not, for some uses of RFID do depend on being able to detect and scan the chip from a distance. I suspect it will find its own niche, based on the new and unique applications it makes possible.

How about a memory necklace? Each bead on the necklace has a Memory Spot, and you can review your data by running the scanner over the necklace. Or a children's book that uses the scanner to play video and sound clips to go with the narrative?


It is worth noting that the basic RFID idea has extensions about which most people have not heard even hints. "Smart dust" was first proposed in 1997 and promptly funded by DARPA (see Jessica Jones, "Dust in the Wind," Government Technology, March 2004). Writing in the March 23, 2003, Computerworld, Thomas Hoffman describes

"'Smart dust' devices [as] tiny wireless microelectromechanical sensors (MEMS) that can detect everything from light to vibrations. Thanks to recent breakthroughs in silicon and fabrication techniques, these 'motes' could eventually be the size of a grain of sand, though each would contain sensors, computing circuits, bidirectional wireless communications technology and a power supply. Motes would gather scads of data, run computations and communicate that information using two-way band radio between motes at distances approaching 1,000 feet."

Some depictions of smart dust suggest the power supply could be handled the same way as for RFID tags, by inducing a current in an antenna with an external radio signal. Given that the chips are larger than most RFID tag chips and they contain sensors and computational capacity, they may be able to accomplish surprising things, beginning with the simple capacity to pass information from mote to mote until it reaches a final destination (motes scattered on a battlefield could report on enemy movements, and feed targetting data to missile batteries or bombers). They might also collect weather data and then--functioning as a large distributed (networked) computer, generate weather forecasts of unprecedented accuracy.

Or they may prove invaluable as environmental monitors. William J. Broad, "A Web of Sensors, Taking Earth's Pulse," New York Times (May 10, 2005), reports that "ecologists are planning to set up more than $1 billion worth of sensor web technology to study diverse environments with an eye toward saving the planet. Dr. Deborah Estrin with UCLA's Center for Embedded Network Sensing says the goal of such deployments is to create the ecological equivalent of MRI or CAT scans... Factors driving the sensor web wave include the support of institutions such as the NSF and the Defense Department, which have respectively financed planning and research into new sensor network deployments and the miniaturization of electronics to yield technologies such as motes and smart dust."

Will "smart dust" pose privacy problems? The sensors it can carry mean that it is not capable only of reporting, like an RFID, what product you bought or own. It can take pictures, record sound, sniff for drugs, and more. It can be scattered in a student's dorm room or clothing. It can be embedded in paint. It is actually much more alarming than RFID tags!

Some people are speculating on what you get if you give smart dust tiny grippers or other movable parts. The name for it now is utility fog, and if RFID tags can be hacked, so can this. And here we have the stuff of nightmares!