how does commercial rfid security tags work?

Question

How do the small 1/2"x1 1/2" security tags work? what happens in the de-activation process?

Answer 1

A RFID or Radio Frequency Identification tag has three parts. Antenna, processor and radio.

Remembering your school physics, a large magnetic field can create electricity in a coil.

* An RFID reader (those poles by the entrance of most stores) generate this large magnetic field.
* The coil gets excited, making enough electricity to power the processor and radio.
* The radio picks up the instructions from the RFID reader, and passes it to the RFID processor.
* processor generates response
* radio transmits information back to RFID reader

There are various ways to "disable" tags. One is sending a signal to the processor to "disable". Which would in the future, in theory would allow, an 'enable' code.

A second, and most often used method is sending such a large magnetic current (when the sales clerk rubs the material on that pad), the electricy generated "fries" the processor and radio making it completely useless. This is why they warn you not to put your credit card on that pad - large magnetic field will wipe your card too.

RFIDs are not much different from bar codes, except they can be read from any angle, and from various distances, and contain substentially more information.

For example - an RFID could in your jug of milk can warn the refrigerator of iminent expiration. Fridge periodically excites all the antennas inside, with each RFID sending a unique detail, such as product name, vendor, maybe price, expiration date, reorder code, purchase method, compatibility, etc.

Just as it can be used for beneficial purposes, it can also be used for malfeasance.