Radio Frequency Identification (RFID)

Radio frequency identification (RFID) is a technology that stores data on a small tag and reads it using radio waves. A tag contains a chip and an antenna; a reader sends out a signal, and the tag replies with its identifier or other data. Passive tags have no battery and draw power from the reader's signal, while active tags carry their own battery and can be read from further away. Unlike a barcode or QR code, a tag does not need to be in view. RFID is used for warehouse and retail stock control, toll roads, building access cards, pet identification and passports. In payments, the short-range form known as near field communication underpins contactless payments by card and phone. Concerns include unauthorised reading of tags at a distance and tracking, which card makers address with encryption and short read ranges.