Wednesday, August 31, 2005

RFI-Duh Heads

It's amazing that RFIDs are becoming so ubiquitous (that may one day completely replace bar codes) and such a possible threat to privacy, yet so many people who the public depend on to talk about them seem completely clueless about the technology.

Lab dedicated to RFID technology
RFID uses a computer chip the size of a grain of rice to store data, which are transmitted wirelessly by a tiny antenna to a receiver. The chips, embedded in tags, now track pallets in warehouses and let drivers pass toll booths without stopping, but its potential is almost limitless.

RFID tags are not computer chips. They contain no computer. They have no memory. They have no power source. They have no processing ability. They're just pieces of metal. If you tried to plug them in anywhere, you would just short out whatever you were plugging them into. They have no ability to transmit data on their own. They are completely passive. RFID's really are advanced bar codes.

RFID tags do not have any antennas. Technically, you could call them their own antenna. However, if you did such a silly thing, you'd have to call bar codes "antennas" too. In fact, you'd have to refer to your own mirror as an antenna.

And that's essentially all an RFID is. It's a big RF mirror. Flash an RF pulse at it and some RF will come back at you. The "shape" of that reflected signal will represent some characteristic of the tag. While I'm glossing over some important details and opportunities for some fascinating discussion, I really haven't abstracted things too far. It would be a major improvement if half of the people who talk about RFID's viewed the devices like a passive reflective device.

I'm not just trying to be snarky here. It's important for people to understand exactly how RFID works, at a basic level, so they know exactly how the Attorney General and Wal-mart will make use of them. This also gives them an idea of what they can do to protect themselves.

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