The most common type of credential is an access card (or badge). The types of cards include:
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Barcode – a unique ID is stored in a barcode on the card similar to the way goods are identified for stocktaking and supermarket checkouts.
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Magnetic stripe – a unique ID is recorded onto a magnetic stripe in a similar way to details on older bank cards.
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RFID (Radio Frequency Identification) – These cards store the unique ID electronically. The cards are read by special RFID readers that communicate with the cards using radio frequency (RF) communications. The technologies used fall into two main categories; proximity cards (125kHz frequency) and contactless smart cards (13.56MHz frequency). RFID credentials are also available as key-fobs or tokens, which are more compact than cards.
Although all RFID systems provide a reasonably high level of security compared to keypads and systems using bar codes or magnetic stripes, there is a wide choice of security levels, with the price of the card usually reflecting the level of security provided, Smart card systems are particularly secure due to advanced encryption techniques and, in certain products, strict control of encoding and distribution.