Overview#Radio-frequency identification (RFID) is the wireless use of electromagnetic fields to transfer data, for the purposes of automatically identifying and tracking tags attached to objects.
The tags contain electronically stored information. Some tags are powered by electromagnetic induction from magnetic fields produced near the reader. Some types collect energy from the interrogating radio waves and act as a passive transponder.
Other types have a local power source such as a battery and may operate at hundreds of meters from the reader.
Unlike a barcode, the tag does not necessarily need to be within line of sight of the reader, and may be embedded in the tracked object.
Radio frequency identification (RFID) is one method for Automatic Identification and Data Capture AIDC.
Since RFID tags can be attached to cash, clothing, possessions, or even implanted within people, the possibility of reading personally-linked information without consent has raised serious privacy concerns.