Keycard lock

A keycard lock, commonly found on commercial buildings and hotel rooms

A keycard lock is a lock operated by a keycard, a flat, rectangular plastic card with identical dimensions to that of a credit card or American and EU driver's license which stores a physical or digital signature which the door mechanism accepts before disengaging the lock.

There are several common types of keycards in use, including the mechanical holecard, barcode, magnetic stripe, Wiegand wire embedded cards, smart card (embedded with a read/write electronic microchip), and RFID proximity cards.

Keycards are frequently used in hotels as an alternative to mechanical keys.

The first commercial use of key cards was at automated parking lots to raise and lower the gate where users paid a monthly fee.^[1]

Overview

Keycard systems operate by physically moving detainers in the locking mechanism with the insertion of the card, by shining LEDs through a pattern of holes in the card and detecting the result, by swiping or inserting a mag stripe card, or in the case of RFID cards, merely being brought into close proximity to a sensor. Keycards may also serve as ID cards.

Many electronic access control locks use a Wiegand interface to connect the card swipe mechanism to the rest of the electronic entry system.

Newer keycard systems use radio-frequency identification (RFID) technology such as the TLJ infinity.

Types

A mechanical keycard, with "bumps" that operate pins inside of the lock (similar to a pin tumbler lock)

Mechanical

Mechanical keycard locks employ detainers which must be arranged in pre-selected positions by the key before the bolt will move. This was a mechanical type of lock operated by a plastic key card with a pattern of holes. There were 32 positions for possible hole locations, giving approximately 4.3 billion different keys. The key could easily be changed for each new guest by inserting a new key template in the lock that matched the new key.^[2]

In the early 1980s the key card lock was electrified with LEDs that detected the holes.

A keycard with a magnetic stripe

Magnetic stripe

Magnetic stripe (sometimes "strip") based keycard locks function by running the magnetic stripe over a sensor that reads the contents of the stripe. The stripe's contents are compared to those either stored locally in the lock or those of a central system. Some centralized systems operate using hardwired connections to central controllers while others use various frequencies of radio waves to communicate with the central controllers. Some have the feature of a mechanical (traditional key) bypass in case of loss of power.^[3]

Passive RFID

RFID cards contain a small chip and induction loop which the transmitter on the keycard reader can access. The main advantages with RFID cards is that they do not need to be removed from the wallet or pass holder - as the keycard reader can usually read them from a few inches away.

Privacy

Computerized authentication systems, such as key cards, raise privacy concerns, since they enable computer surveillance of each entry. Currently RFID cards and key fobs are becoming more and more popular due to their ease of use. Many modern households have installed digital locks that make use of key cards, in combination with biometric fingerprint and keypad PIN options. Offices have also slowly installed digital locks that integrate with key cards and biometric technology.^[4]

Gallery

Wikimedia Commons has media related to Access control systems and Electronic locks.

Illustrations of Authentication Access Control & Keycard Technology
A hotel entry card and used as a light switch  Illustrated instructions for use of mag stripe key card  Electronic Lock with Keycard System, ANSI  Access control utilizing magnetic strip technology

See also

• Access control

References