An access badge is a credential used to gain entry to an area having automated

access control In the fields of physical security and information security, access control (AC) is the selective restriction of access to a place or other resource, while access management describes the process. The act of ''accessing'' may mean consuming ...

entry points. Entry points may be

door A door is a hinged or otherwise movable barrier that allows ingress (entry) into and egress (exit) from an enclosure. The created opening in the wall is a ''doorway'' or ''portal''. A door's essential and primary purpose is to provide security b ...

turnstile A turnstile (also called a turnpike, gateline, baffle gate, automated gate, turn gate in some regions) is a form of gate which allows one person to pass at a time. A turnstile can be configured to enforce one-way human traffic. In addition, a ...

s, parking gates or other barriers. Access badges use various technologies to identify the holder of the badge to an access control system. The most common technologies are

magnetic stripe The term digital card can refer to a physical item, such as a memory card on a camera, or, increasingly since 2017, to the digital content hosted as a virtual card or cloud card, as a digital virtual representation of a physical card. They share ...

, proximity,

barcode A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly referred to as linear or o ...

smart card A smart card, chip card, or integrated circuit card (ICC or IC card) is a physical electronic authentication device, used to control access to a resource. It is typically a plastic credit card-sized card with an embedded integrated circuit (IC) c ...

s and various

biometric device A biometric device is a security identification and authentication device. Such devices use automated methods of verifying or recognising the identity of a living person based on a physiological or behavioral characteristic. These characteristics ...

s. The magnetic strip ID card was invented by

Forrest Parry Forrest Corry Parry (July 4, 1921 – December 31, 2005) was the IBM engineer who invented the magnetic stripe card used for credit cards and identification badges. Parry was born in Cedar City, Utah to Edward H. Parry and Marguerite C. Parry. Fo ...

in 1960.Southern Utah University in View, Fall 2004, Alumni Awards, pages 3-4
{{webarchive, url=https://web.archive.org/web/20111027061240/http://www.suu.edu/alumni/magazine/fall04/pdf/news.pdf , date=2011-10-27 The access badge contains a number that is read by a card reader. This number is usually called the facility code and programmed by the admin. The number is sent to an access control system, a

computer system A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...

that makes access control decisions based on information about the credential. If the credential is included in an access control list, the access control system unlocks the controlled access point. The transaction is stored in the system for later retrieval; reports can be generated showing the date/time the card was used to enter the controlled access point. The Wiegand effect was used in early access cards. This method was abandoned in favor of other proximity technologies. The new technologies retained the Wiegand upstream data so that the new readers were compatible with old systems. Readers are still called Wiegand but no longer use the Wiegand effect. A Wiegand reader radiates a 1" to 5" electrical field around itself. Cards use a simple

LC circuit An LC circuit, also called a resonant circuit, tank circuit, or tuned circuit, is an electric circuit consisting of an inductor, represented by the letter L, and a capacitor, represented by the letter C, connected together. The circuit can a ...

. When a card is presented to the reader, the reader's electrical field excites a coil in the card. The coil charges a

capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...

and in turn powers an

integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...

. The integrated circuit outputs the card number to the coil which transmits it to the reader. The transmission of the card number happens in the clear—it is not encrypted. With basic understanding of radio technology and of card formats, Wiegand proximity cards can be hacked. A common proximity format is 26 bit Wiegand. This format uses a facility code, also called a site code. The facility code is unique number common to all of the cards in a particular set. The idea is an organization has their own facility code and then numbered cards incrementing from 1. Another organization has a different facility code and their card set also increments from 1. Thus different organizations can have card sets with the same card numbers but since the facility codes differ, the cards only work at one organization. This idea worked fine for a while but there is no governing body controlling card numbers, different manufacturers can supply cards with identical facility codes and identical card numbers to different organizations. Thus there is a problem of duplicate cards. To counteract this problem some manufacturers have created formats beyond 26 bit Wiegand that they control and issue to an organization. In the 26 bit Wiegand format bit 1 is an even parity bit. Bits 2-9 are a facility code. Bits 10-25 are the card number. Bit 26 is an odd parity bit. Other formats have a similar structure of leading facility code followed by card number and including parity bits for error checking.

Smart cards A smart card, chip card, or integrated circuit card (ICC or IC card) is a physical electronic authentication device, used to control access to a resource. It is typically a plastic credit card-sized card with an embedded integrated circuit (IC) c ...

can be used to counteract the problems of transmitting card numbers in the clear and control of the card numbers by manufacturers. Smart cards can be encoded by organizations with unique numbers and the communication between card and reader can be encrypted.

References

Identifiers

See also

References