What is the difference between Prox and Contactless card/reader technologies?
In using the two technologies purely for access control, there really are no visible differences. With either technology you simply present a card to a reader and rather quickly access is either granted or denied, usually through both audible and visual means (beeper and LED). However, what you cannot see may be of significant importance. The transaction between a typical prox card and reader is a “license plate” transaction, meaning that as a card is presented to a reader, the card transmits a static number “in the clear” (through radio frequency communication a number is sent to and received by the reader). The number is the same every time the same card is presented. Conceivably, with the proper equipment, this number could be captured by someone skilled in RFID technologies and then replayed to the reader at a later time to gain unauthorized access. In comparison, a secure contactless smart card and reader transaction generally contains a much higher level of security. When a card
