I am surprised I never responded to this thread.
I have one of the most highly polished Tin-Foil Hats around, but I am not terribly worried about RFID, not the commercially advertised incarnations anyway.
I work as the IT manager for the largest RFID company in the world. We are *the* supplier of RFID tags and devices to the DoD. With the tags and devices available from my company, Matrics, Alien etc.. you needent worry. These tags are too expensive, too big and too weak to be of concern to people. (Expensive being the primary gating item to ubiquity)
However - i would remind people that a cell phone is far more an unknown and exploitable device than the current commercially advertised and known RFID tags.
RFID is a phenomenon that has been known about for a long time. (as are cell phones which were first proofed in the 40s) and as mentioned falls into two categories. Active or Passive. Active tags have a battery which powers the antennae - passive tags merely respond to RF waves that pass throguh them and "reply" with a unique signature.
Passive tags hold very little data, usually just an ID - or serial number. Active tags have memory and can hold real data, such as the manifest of a shipping container.
The data still needs to be read and dealt with in a meaningful way. Passive IDs need to be correlated to a backend DB which equates the ID with some meaningful data, such as a record of what that ID actually represents.
Active tags are a bit more flexible in that they can provide info which does not necessarily require the backed DB to understand what the tag is identifying, or what that container holds.
My company, Savi Technologies, only produces Active tags. These tags are large, expensive and meant for tracking THINGS. Containers specifically - or large cost items, such as a vehicle. Our tags are used on shipping containers and trucks, and pose no threat to personal privacy, unless you dont want people (yourself) to know what you placed inside some container which is being shipped from one port to the next.
Active tags, backed by batteries, arent just capable of greater range, they are capable of TELLING the reader system about events that occur. For example - we have some tags which have sensors on them. Light, temp. humidity, shock etc. These sensors can be set to alert if they go off or above threshold. This is important when you are concerned about the viability/integrity of the property the tag is "watching". Some medications spoil if exposed to certain temperatures for extended periods of time. The sensor tag can monitor temp then alert if it gets too high for too long. Some munitions automatically ARM themselves if they receive a certain amount of shock. so the tags would warn if a munition is armed, important to know if your going to be moving a box of explosives via crane or forklift.
Active tags cost between 60 and 85 dollars per tag. Are roughly 4" long and 1" high and 1.5" wide. Active tags run at 433 megahertz and 123 kilhertz (the two frequencies are used for two different functions: reading data from the tag (433) or sending commands to the tag (123)).
There are some new active tags which are smaller, and run on 802.11 (wifi) frequencies, but there are a great number of challenges in that freq. range.
Passive tags are a losing proposition for most companies as the manufacturing cost is greater than what the tag can be sold for. Before tags can be ubiquitous in products - they need to be throw-away cheap. some person I dont know said that the magic number for passive tags was .05 (a nickel) - but one thing that hasnt been talked about with regards to the mass use of RFID is the backend databases and logic application required to actually do anything with the data read from tags. This obviously implies the reader infrastructure as well.
There is a lot of supporting infrastructure required to do anything of interest with RFID - its not jsut that you dfeploy a bunch of tags and all of a sudden you can track people.
You need to know what location each reader is at, you need to be able to tell tags where or who they are. What if people move tags around and put them on things that are not the original item tagged? Then you have false data.
anyway - if anyone has any other questions about RFID and how its used and what they should worry about - post it here...
since this thread was started, google maps has gone live and you can get a much better picture of denver airport on it.
In closing, one of the interesting things I read in this thread was montalks quoted posting of the transdimentional gate at the (denver) airport. What more perfect a place to put a thing like that than at an airport. Streams of people come out of the airport, and nobody would question them walking out of the airport as being anything other than one who arrived via plane.
It would be interesting to count the number of people leaving the airport and compare that with the number of flights (or terrestrial planes).
"It's hard to advance freedom in a country that has been strangled by tyranny." - G.W. Bush 04/13/2004
