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A Technical RFID Primer
gManZboy writes "Roy Want, principal engineer at Intel Research, has a pretty meaty technical overview of RFID up at Queue. If you ever wondered how these little things actually work it's worth a read. For instance, I was intrigued to find out how the tags (which are generally battery-free) can absorb enough energy from RFID readers to then power up and transmit their own signal back to the reader."
Are they biodegradable?
vicious, untreated political sewage...niche entertainment for the spiritually unattractive...worshipless pap
I am looking into wiring the office with RFID readers and equipping the engineers with RFID tags that will allow them to beep in and out of the office. Without a valid tag, the doors would not unlock. I've seen this done with smart cards previously, but would like to do it with a more lightweight technology.
The most obvious security risk is that someone steals a tag and enters the premises unnoticed. But there are others that I worry about. Stuff like the ease of replicating an RFID tag or even a hacker passively reading a tag in public then recreating it and gaining access.
I understand the problems many people have with RFID, especially stuff like tracking of purchased items and the like, but I'm more interested in using it for security clearances. Unfortunately, the web is not full of information about this (whereas it is full of information about how RFID is a privacy threat). More information about the practical uses of RFID would be greatly desired.
From the article,
In fact, various forms of crude RFID have been used since World War II.
What I think he is refering to but failing to mention by name is the aircraft friend or foe reflector. A tuned cavity was placed on an air craft that would reflect a radar signal many times inside the cavity then emit it back. This delay produced a second reflection to a radar scan. If the shadow image of the plane was on the display, it was a Friend. If it was absent, it was a Foe. It was known as a FOF transponder. (Friend Or Foe)
It has been upgraded to return the plane identification.
The truth shall set you free!
You and the tinfoil-hat crowd will all get these jammers, and when you get to the checkout, you will likely disrupt all the item scanners within a 10 ft. radius. Meanwhile, it takes all the register-jokeys 15 minutes to sort out th problem, and I have to spend 15 minutes longer at the jumbo-mart than I had to.
If you're paranoid that the FBI is tracking you and your chiuaua, then start microwaving all your jeans at home, or go live in a cabin for all I care. But please *do not* inconvience me while I am already stressed out at the till, or you may end up with an ass whooping.
I hopethey outlaw these things in public places. It is a trivial matter to wipe any RFIDs on things you buy once you get home (most would likely get nuked during the wash anyways - do you have any idea how much static electricity your dryer makes?), so "tracking you" is hardly a goal of this crap.
Nuking a tag in the microwave will break it. Running it through your electric dryer will likely break it due to static buildup. So none of your clothes have working tags, you buy a wallet maybe once every 2-3 years - so what are they "tracking you" with?!?! The TV that sits in your house 24/7 and emits so much RF that it can attract air search+rescue?
This is why all these privacy nuts are just uninformed wackos.
For a complete developers guide you can check EM Microelectronic-Marin SA Application Note
However for and introduction, check Wikipedia, or if you just want to start play with it, take a look at some RFID readers.
The passive devices that power up and send back data have nothing on the crystal radios that were used during the 1930's and 1940's. With nothing but an antenna a few feet or yards long,a semiconductor(crystal) and earphones, it was possible to receive enough power to hear radio stations. The so called "Fox Hole Radio" of World War II used a pin made of tin and to contact a "Blue Blade" razor to make the crystal. This simple setup received enough power from the antenna to give audible power to the earphones. I duplicated this years later but used a 1N34 germanium crystal. (And no, you don't need a tuning circuit if you have one strong signal and the others are weak.) The blue blade razors were out of production before I knew that they could be used.
Before this we had swipe cards. Now all we have to do is walk up to the door and the door reader will go beep and open the lock.
I have been trying to open it up to take a look but it's complete sealed. I have been told it's water proof, heat proof and so on. It's labelled by a company called Sonitrol. Their website is at http://www.sonitrol.com/ but it doesn't show any actual products.
The article states, that metal containers (say, a can of coke) and RFID tags don't match well. Is this really true? What if the RFID tag's antenna connects to the metal? Wouldn't the metal become a bigger antenna, thus increasing the range?
cpghost at Cordula's Web.
... used by Exxon (and called Speedpass), I can tell you that they are pretty cool in technology... and yet lame at the same time.
Yes, it is true, there is a blast of energy (usually at a really low wave length - around 100Khz to 180Khz - they aren't very well tuned despite the lit).
For the paranoid, chewing gum wrappers do a good job of blocking them. Actually, a lot of tinted windshields do a good job as well (they tend to contain metal, typically iron from what I am told).
Interference is a big factor with these guys. A noisy engine (spark plugs badly gapped?) can cause problems. But the end result was that the company bought it.
Do I fear the use of it? Not really. But at the same time I don't like them used without my permission. As any device that is used to "track", it needs to have my consent.
That said, they are kinda' cool.
IANAL, but I've seen actors play them on TV
I wasn't. That was a joke. I thought "Chairman Meow" sort of tagged it as such. That was the name of a cat P. J. O'Rourke once owned, BTW.
10 feet is plenty of space on most streets, restaraunts or bars to find out if someone is worth mugging.
I just don't think anyone is going to bother. Common criminals have lots to go high tech with now, and the most sophisticated thing they tend to use is a cell phone. Lead pipes and boomsticks are still the tools of choice. There are plenty of tried and true ways to evaluate a target.
Purse snatchers roaming the streets with high tech scanner bling just sounds like so much cyberpunk feverdreaming. The bright but misguided street punk only exists in moovies and William Gibson novels. I used to do some work in college that brought me into contact with lots of these people. They are not the hacking type, unless you mean the hacking coughs from years of biochemical self abuse.
The truly sophisticated criminals have bigger fish to fry than what they can get from a mugging or from seeing if I'm wearing fancy, high-end BVDs.
The idea that someone not only knows the manufacturer and model of my shirt, but whether or not I'm wearing boxers or briefs gives me the ebee-jeebies.
See I just don't get that. Who cares? I think it's bizarrely egotistical that you expect someone to care.
Unless you are wearing undies not intended for your gender?
Oh, my, I think we have struck upon the problem. ;-)
--- Ban humanity.
Also, a longstanding dream of mine is the wireless light switch. It could signal back its state to to an EM transponder in each room. Light switches would then be affixed to walls with blu-tack or whatever. This sounds kind of geeky, but perhaps it would be cheaper than re-wiring a wall? Would this work?
"I just don't think anyone is going to bother. Common criminals have lots to go high tech with now, and the most sophisticated thing they tend to use is a cell phone. Lead pipes and boomsticks are still the tools of choice. There are plenty of tried and true ways to evaluate a target."
They use more than that. Read the November issue of Popular Science. Page 88.