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Smartcards and Proximity Cards:
Proximity Cards - Both Clam Shell and Printable
Proximity card (or Prox Card) is a generic name for
contactless integrated circuit devices used for security
access or payment systems. It can refer to the older
125 kHz devices or the newer 13.56 MHz contactless RFID
cards, most commonly known as contactless smartcards.
Modern
proximity cards are covered by the ISO/IEC 14443
(Proximity Card) standard. There is also a related ISO
15693 (Vicinity Card) standard. Proximity cards are
powered by resonant energy transfer and have a range of
0-3 inches in most instances. The user will usually be
able to leave the card inside a wallet or purse. The
price of the cards is also low, usually US$2-$5,
allowing them to be used in applications such as
identification cards, keycards, payment cards and public
transit fare cards.
(image -
Clam Shell Prox Card)
Proximity ca rds use an LC circuit. An IC, capacitor, and
coil are connected in parallel. The card reader presents
a field that excites the coil and charges the capacitor,
which in turn energizes and powers the IC. The IC then
transmits the card number via the coil to the card
reader. The card readers communicate in Wiegand protocol
that consists of a data 0 and a data 1 circuit. The
earliest cards were 26 bit. As demand has increased bit
size has increased to continue to provide unique
numbers. Often, the first several bits can be made
identical; these are called facility or site code. The idea is that company Jane has a facility code of xn and
a card set of 0001 through 1000 and company John has a
facility code of yn and a card set also of 0001 through
1000.
(image - Printable Prox
Cards)
Smart cards come in two forms, contact and contactless.
A smart
card is a small, tamperproof computer. The smart card itself contains a
CPU and some non-volatile storage. In most cards, some of the storage is
tamperproof while the rest is accessible to any application that can
talk to the card. This capability makes it possible for the card to keep
some secrets, such as the private keys associated with any certificates
it holds. The card itself actually performs its own cryptographic
operations.
Although smart cards are often compared to hard drives, they’re “secured
drives with a brain”—they store and process information. Smart cards are
storage devices with the core mechanics to facilitate communication with
a reader or coupler. They have file-system configurations and the
ability to be partitioned into public and private spaces that can be
made available or locked. They also have segregated areas for protected
information, such as certificates, e-purses, and entire operating
systems. In addition to traditional data storage states, such as
read-only and read/write, some vendors are working with sub states best
described as “add only” and “update only.”
Contactless Smartcards
Contact cards
require a reader to facilitate the bidirectional connection. The card
must be inserted into a device that touches the contact points on the
card, which facilitate communication with the card’s chip. Contact cards
come in 3-volt and 5-volt
models, as do current desktop CPUs. Contact card readers are commonly
built into company or vendor-owned buildings and assets, mobile phones,
handheld devices, stand-alone devices that connect to a computer
desktop’s serial or Universal Serial Bus (USB) port, laptop card slots,
and keyboards.
Contact Smartcards
 Contactless
cards use proximity readers to get information to and from the card’s
chip. An antenna is wound around the circumference of the card and
activated when the card is radiated in a specific distance from the
reader. The configuration of the card’s antenna and the coupler
facilitate connected states from a couple of centimetres to a couple of
half a metre. The bidirectional transmission is encoded and can be
encrypted by using a combination of a card vendor’s hard-coded chip
algorithms; randomly generated session numbers; and the card holder’s
certificate, secret key, or personal identification number (PIN). The
sophistication of the connection can facilitate separate and discrete
connections with multiple cards should they be within range of the
coupler. Because contactless cards don’t require physical contact with a
reader, the usability range is expanded tremendously.
International standards govern the physical characteristics of smart
cards. For example, the size of a card is covered by International
Organization for Standardization (ISO) 7810. ISO 7816 and subsequent
standards cover manufacturing parameters, physical and electrical
characteristics, location of the contact points, communication
protocols, data storage, and more. Data layout and format, however, can
vary from vendor to vendor.
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