| 摘要 |
<p>A passive device shield 2 used to protect a passive chip containing data embedded in a device from remote skimming. The shield is removable to enable authorised reading of the chip data. The shield is adapted to block the frequencies which activate the chip. The shield also has a transmitter (18) which sends a coupling signal at a non-blocked frequency to a receiver (20) At least one of the receiver and transmitter has means to monitor the distance between the transmitter and receiver, and an alert means to indicate when a predetermined distance has been exceeded. In another embodiment a network of receivers is arranged to locate and track the shield. The shield may be laminated and may include layers, of fabric, metals (e.g. copper), and paramagnetic/diamagnetic material. The device may find application to passports or airport boarding passes.</p> |
