An access control system is designed to ensure that persons accessing information and facilities are appropriately credentialed. The components of an access control system are smart chips with verification data, access control card readers (also known as readers or controllers), access management software that tracks identities and their authorizations, and access control panels, the physical hardware that enables doors to open once the authenticity of the chip's login credentials has been confirmed. In an access control system, login credentials can range from passwords to biometric scans to access control cards, also known as prox cards or proximity cards.
Access control systems include credit cards and card readers that can make wireless transactions with just a tap, key fobs and door readers that grant access to apartment buildings, and proximity cards that share identifying details with access controllers to gain access to secure sites and information.
A proximity card, or "prox card," is a form of login credential that contains a smart chip with a unique serial number. When in close range of an access control panel, the card's smart chip is activated to enable the wireless exchange of information. The controller then reads the card to authenticate the identity of the cardholder and authorize specific privileges.
Proximity cards are able to exchange information with chip readers when brought within a close range, usually 4 centimeters or less. This communication is possible because of Radio Frequency Identification (RFID), a technology that conveys information through electronic wavelengths between antennae in the chip and antennae in card reader.
The chip and reader communicate using binary data--the computer language of positive and negative bits (or zeros and ones) arranged in meaningful patterns. The first bits in the series of an access card give the card reader essential information about the card's format--how to categorize and interpret its sequences of bits. Basic card format information includes the number of bits the card has and what individual sections of the format represent.
A card for gaining entrance to a secured area will likely include a format with details such as the company ID code and facility code--and ultimately the credential number or serial number that will tell the reader the identity of the cardholder.
The most common card format is the Wiegand format 26 bit card. These 26 bit cards are open format, meaning card manufacturers do not need permission to produce and sell them. Because there are so many Wiegand format cards, they include a second number known as a facility or site code. The facility code prevents situations in which two companies may end up with interchangeable cards.
Proximity cards are also available in 32, 33, 35, 37, 48, and 50 bit formats. Cards with more bits offer better security than the open format variety, but their proprietary formats usually also come with a higher price tag. The one exception is the 37 bit proprietary format card, which is made by HID Global and is priced similarly to the standard 26 bit format cards.
Proximity cards are an essential tool for companies seeking to increase security while maintaining a smooth operation. Near-field communication via radio frequencies allows for a speedy and secure process of credential authentication before access to sensitive information or facilities is granted.