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              Outbreak Magazine Issue #15 - Article 1 of 11
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RFID Technology Primer
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by cxi (cx.i@s-mail.com) of compulsive.org

Radio Frequency Identification (RFID) technology has made a lot of press lately, as more and 
more companies are going public about using it on their products such as Benetton and Prada 
clothing companies. The CVS drugstore chain also announced that it would begin trying the 
technology in its stores. Once I explain the way this technology works you will begin to see 
the many privacy concerns that will be raised by widespread unrestricted use of this technology.
Generally RFID systems involve a transmitting tag (known in the industry as the transponder) 
and a tag reader station. When the tag is to be read, the station emits a power pulse to the 
tag, which collects the magnetic field with its antenna and tunes to the same frequency. Passive 
tags then store the energy in a capacitor on the tag. The tag then transmits information via RF 
to the station (e.g. product number, clothes size/color, etc). After transmission (lasts ~20ms), 
the passive tags discharge the capacitor to reset it for any future transmission. The station 
then either processes and stores the information into a database or displays it to a human 
system user. Popular frequencies for RFID operation are 125KHZ, 13.56MHz, 868-915MHz, and 2.4 
or 5.8GHZ. These frequencies differ in range from .5 to 3 meters, price, as well as how they are 
powered (passive tags with inductive coupling for the two lower frequencies or possibly active 
with integrated batteries for the higher frequencies). It's also interesting to note that data 
speed gets faster at higher frequencies, but higher frequencies are more susceptible to 
interference near metal or wet objects.

Companies could use this for inventory control, be able to ring people up much more quickly than 
by using an infrared reader, employee identification to enter employee-only areas, Lo-Jack-style 
vehicle tracking systems, etc. RFID is actually widely in use today with electronic tolls 
(FastLane/EZPass in MA/NY), Mobil SpeedPass, etc. Most of these sound like pretty useful things, 
and I agree it could be a very useful technology. The problem though, as with most privacy 
concerns, is with control. Who controls when these devices will transmit what and to whom? Who 
controls whether or not my clothes will tell the GAP what I'm wearing every time I go into the 
store? Unfortunately privacy issues aren't really being discussed openly by businesses 
implementing this technology. 

The privacy concerns come up after the tagged products leave the store, and as far as businesses 
are concerned  once it leaves the store it  not their problem. Some companies, such as Wal-Mart, 
say they will disable the tag when the purchased product leaves the store  but a) how does one 
know for sure? and b) it  not exactly uncommon to walk out of a store with one of those big 
annoying security tags still on a piece of clothing now  who  to say they l always remember to 
either remove or disable the RFID tag on every single one of their products after it  purchased? 
MIT-affiliated Auto-ID Center is saying that tags they develop will have a kill feature built in 
that can be switched by a cheap reader. But giving these to the businesses still leaves the above 
problem of forgetfulness, and giving it to consumers leaves the problem of vandals taking them 
into stores and walking up and down the aisles turning off tags. For more information on the 
privacy implications of RFID tags, see the No Cards website on it: 
http://www.nocards.org/AutoID/overview.shtml. After researching what RFID tags are, how theyre 
being used, and how they could be abused, I became extremely interested in ways to make my own 
kill switch in the event that not too far in the future Im walking around with a micro-radio 
station in my jeans. First, I looked at what the RFID tags are sensitive to  my first thought 
was RF Interference, a big concern for any RF application this interference could come from 
signal collision or proximity to metal or wet objects (e.g. if the tag on your shirt was too 
close to your watch it wouldnt work). The other thing they are sensitive to is distance, but as 
I dont know where every companys reader stations are placed, this probably isnt something we 
can get around. MobileCloak.com offers a solution I hadnt thought of  bags made out of special 
material (most likely something partly metallic) that you can place devices, such as a cell 
phone, in to avoid privacy invasions. Unfortunately, I dont think its wise to walk around with 
all of my clothes in one of these bags, nor would it be any fun to wear clothes made out of it 
all the time. I have also yet to actually figure out a method of creating a device that would 
cause radio signal interference that a) would work for the various frequency tags and b) not 
interfere with other devices such as my cell phone. Im very interested in studying this further 
and urge everyone to pay attention to the news to see which companies are adopting this 
technology so you know before you buy that your purchases are being tracked even more than you 
think.
	If anyone who as experience with RF transmitting or radio technology in general would 
like to work with me on this project to shield out RFID tag transmissions, please contact me.

For further information check out these sites that I used in my research:
http://www.rf-id.com
http://www.autoidcenter.org
http://www.mobilecloak.com
http://www.samsys.com