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NYT on RFID
The New York Times has a piece on RFID tags. It's basic, but worth reading as a milestone - the technology is starting to enter the public eye. These RFID tags will have unique serial numbers - every RFID-tagged item you purchase will be uniquely different from every other nearly-identical item, enabling it to be identified and associated with you long after the purchase. And no, microwaving will generally not destroy the tags, and no, most items won't be microwaveable anyway. Try to microwave your couch.
Ha! I laughed at my buddy a few years back when he said that the U.N. could fly over your house and scan it to see how much money is in it. Now that is a reality. The RFID tags would be useful for inventory purposes, but the privacy thing is hard to shake. Who says that "advanced" criminals in the future won't develop a "super RFID scanner" and scan all of the houses in a neighborhood and "see" what goodies are in each house to try to figure out which house to rob. OR the government can use it to see which house is guilty of thought crime! :)
"Jeremy, you need to get to an internet cafe and cut and paste some appropriate sentiments about me from the world wide
But what is worrying is when information about you is used in ways to control your behaviour. For instance, if you are thinking about quitting smoking and purchase the patches to help with the cravings. Those interested will track your movements along with the movements of other "quitters" to place smoking triggers along your path to make it that much hard for you to shake the habit.
Perhaps you're a person who has bought a lottery ticket or two. Suddenly you're flooded with all kinds of gambling offers. Sure, you can say no to their offers, but what will others think when they see you getting that barage of junk mail to visit all those cassinos? What will your boss think when they start sending those offers to your office?
Most of us live lives of moderation. We like to take in occasional vices, but we mostly try to keep things pretty mundane. But this isn't allowed in the corperate world. They have to seek out potentially new exploits to justify getting an MBA. Any information that they can get will allow them to find a wedge between you and your better judgement.
I know, I know... You're too smart for their tactics. You're in control of your own destiny. It doesn't bother you when they mercilessly pick away at you. You're just content to sit back in your recliner watching "Matlock" re-runs on cable.
The sad part is, people don't see any value in privacy, because they don't realize the benefits it allows. Being anonymous allows you to have your turn next in line, and receive the same amount of respect as a person who is twice as affluent as your are. Once your personal worth is on the table with everyone else's, your value in society has just been broadcasted, and you will wait until those more worthy have been served no matter how long you've been waiting. You may never be served at that rate...
Oh, but you'll just head on to their competitors, right? Think again. They bought the same list. They also know that you'll be more desperate than before since they knew where you were coming from... Now they can really ream your wallet *IF* they decide you're worth having as a customer.
Privacy also allows you to be forgiven for your past mistakes more easily. Who hasn't made a mistake or exercised poor judgement when they were more youthful? It's the foundation of experience, but if your subordinates know every detail, they aren't as likely to be as subordinate. How can you credibly jump on them for making the same mistakes you used to?
Privacy has a very real value for people in society. It's not just about dirty magazines or illicite affairs. It's about not having to worry what the score is every moment of your life. It about not having to be publicly humiliated at unexpected moments. It's about maintaining person dignity and self-respect.
If you don't have any respect for yourself to keep private things private, how can you expect anyone else to respect you as well?
You don't have to disable RFID tags to screw with the data collection and tracking systems. If you are able to find and collect RFID tags you can carry them around with you wherever you go. Imagine having three or four car RFID tags on you as well as about a hundred refridgerator RFID tags. Dumpster diving for RFID tags would be great fun. You'd have tags from stuff that never really led back to you and would confuse the hell out of anyone trying to make sense of the history of the items. You could do things like remove all of the RFID tags from your clothes and keep only one RFID tag in your wallet that was from a pair of underwear. If anyone looked at the data they'd think some guy in the same pair of underwear he's been wearing for weeks is walking around carrying a few cars and a bunch of Refridgerators.
This would be much more fun than filling our frequent shopper cards with bogus information or completing surveys with ridiculous answers.
The RFID chip works in conjunction with a tuned circuit {capacitor and coil; the coil also behaves as an antenna} that extracts energy from an applied RF field. The resonant frequency of this tuned circuit is the operating frequency for the system. The size of the coil determines the operating range. An RFID device with integral tuned circuit measures about 20mm. by 10mm. by 2mm. and has a range of a few cm. A smaller device would require an external coil, but the bigger coil would extend the working range.
The transmitter feeds an RF power amp with a sensitive ammeter in one of its power supply leads.
Now, when the tuned circuit is brought within range of the transmitter, it will pick up the signal. But that is all. A voltage will be induced across the system, and a current will flow, but they will be out of phase. When the voltage is at a peak, the current is nil, and vice versa. Recall that power = voltage * current, so there is no power. Bringing the tuned circuit into range of the transmitter will not affect the ammeter reading.
However, if you connect a resistance across the two ends of the tuned circuit, then the current across this resistance will be in phase with the voltage. Energy is now being changed from electromagnetic waves to heat. And, strictly in accordance with the first law of thermodynamics, the reading on the ammeter will go up. Reduce the resistance and it will go up more. Of course, the imperfect coupling from transmitter to receiver itself behaves like a big resistance, which effectively limits the power available for the receiver {and therefore the ammeter swing}.
Anyway, if we switch this resistance in and out of circuit, we can watch the ammeter moving in sympathy with the switching.
The RFID tag gets its power by rectifying the AC induced in the tuned circuit, and using this to charge a capacitor. This capacitor stores enough energy to allow the tag to miss a few cycles, because it unavoidably will as a consequence of how it works. The tag then switches on and off a transistor which sits across the bridge rectifier {a transistor only conducts in one direction} in accordance with a predefined pattern. When the transistor turns on, more power is drawn from the transmitter. {As a side effect, the voltage is pulled down and the RFID tag has to rely on the capacitor contents to keep in this state, remember how far through the sequence it is, and so forth; so this state lasts only a few cycles}. The transmitter can see, by measuring the supply current to the RF power amp, whether the transistor in the RFID tag is on or off.
The external RF field also provides a stable timing reference to the tag, because it can count cycles accurately and dead-reckon a few cycles when it has to.
So, we have a one-way communication from the RFID tag to the transmitter, even though the RFID tag has no power supply of its own. If the RFID tag is absent or high resistance, this is a zero. When the RFID tag goes low-resistance, the transmitter can see this as a one. This allows us to send a binary number from the RFID tag.
All the RFID tag does, once it comes into range of the transmitter, is continuously send out a series of zeros and ones by going low and high resistance. It is up to the transmitter to spot the resistance of the remote end.
It is also possible to send data to the RFID tag, by switching the RF field on and off. While this could be used for programming of tags with serial numbers {instead of laser etching as is currently done}, it would require the tag to have some sort of EEPROM or Flash memory. These devices currently have a high power demand making them unsuitable for operation on RF power alone, but recall Clarke's first law: When a scientist says something is possible they are usually right; when a scientist says something is impossible they are usually wrong. So it is almost certain that future RFID tags could be reprogrammable.
The canonical method for deactivating
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