Patent US 7,239,240

Disclosed is one method and one apparatus which teach improved techniques in equipping an RFID with security measure. Conventionally an RFID is employed basically to replace the usage of an infrared bar-code label thereby to supply electronic or digital signature and identification. In this sense, the traditional RFID technology is in lack of security and an RFID can be tampered with in an arbitrary manner not to cause an alert. This is no longer true if an RFID is endowed with security. In this invention an RFID, either an active or a passive device, has the ability to memorize its original spatial position so that if the position is changed without authority, an alarm signal is generated.