UFC 4-021-02NF
27 September 2006
change 1, 23 October 2006
3-4.7
Card Types. Card readers use a number of different card types, the most
common in use are described in the following subsections.
3-4.7.1 Magnetic Stripe Cards. Magnetic stripe (mag stripe) cards consist of a
magnetically-sensitive oxide strip fused onto the surface of a PVC material. They are
inexpensive, easily manufactured, and can carry alphanumeric data. (Magnetic cards
used within the DoD should comply with SEIWG-012, which specifies numeric data
only.) A magnetic stripe card is read by swiping it through a reader or by inserting it into
a position in a slot. A magnetic stripe card can be individualized by color coding the
cards and printing photo information onto them. The magnetic stripe card is
disadvantaged in that it may be physically damaged by misuse and its data can be
affected by magnetic fields, even when they are of only low potential. Other problems
associated with this type of card are related to the high volume of equipment available
for the reading and copying of cards so that unauthorized duplication and copying can
never be entirely negated.
3-4.7.2 Proximity Cards. Proximity cards (prox cards) use embedded antenna wires
connected to a chip within the card. The chip is encoded with the unique card
identification. Currently, the standard proximity card operates at a frequency of 125kHz.
Distances at which proximity cards can be read vary by manufacturer and installation.
Readers can require the card to be placed within a fraction of an inch from the reader to
six inches away. Having the card out and at the same height of the reader, background
electrical interference levels, and sensitivity of the reader affect the distance at which a
card can be read. Proximity card technology (125kHz) should not be confused with
wireless, contactless (13.56MHz) technology.
3-4.7.3 Wiegand Cards. The following information is cited from Effective Physical
Security (page 196):
The Wiegand card is also called an embedded-wire card. The technology is
based on the Wiegand Effect, a phenomenon observed when specifically
prepared ferromagnetic wires suddenly reveres themselves on exposure to an
external magnetic field. Wires inside the Wiegand card are formed in a
permanently tensioned helical twist. The order and spacing of the wires
establish a unique code for each card. The magnetic reversals in the wires are
converted into distinct, consistent electrical pulses that are read and
processed. The card's thickness and stock composition make it resistant to
pocket damage; however, it is susceptible to malfunction arising from wear
after many passes through reader slots. The card is moderately priced, but
capable of storing a moderate amount of data.
3-4.7.4 Smart Cards. Smart cards are credential cards with a microchip embedded in
them. The term "smart card" can define cards that simply carry data, but more
commonly is used describe cards with integral microprocessing and read/write data
storage capability. Smart cards are available as a "Contact" type or more commonly as
a "Contactless" (and wireless) type. An example of a "Contact" smart card is one which
can interface to a computer through the embedded contact. The contactless, wireless
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