Contactless cards are chip cards consisting of a coupling element and an electronic microchip (smart chip). The information data is transmitted to the reader from the card using radio frequencies.
There are two kinds of contactless chips: passively powered and actively powered. Passively powered chips do not include a power supply and must use the electromagnetic energy (inductive coupling) transmitted by the reader. Actively powered chips include their own power supplies. For use in individual access control situations involving ID cards, only the passively powered contactless cards are of interest.
The domains where contactless cards are used includes: public transportation ,E-ticket, payment, hotel key lock, access control, time attendance system.
Figure 1. Smartcard being used to pay for public transportation
Figure 2. SecuraKey eTag Quasar - Read & Write Contactless Smart Cards " />
Three contactless technologies have received standard classification from the International Standards Organisation (ISO):
- .ISO/IEC 10536 close coupling cards
- ISO/IEC 14443 proximity cards
- ISO/IEC 15693 vicinity cards
The first was the ISO/IEC 10536 close coupling card technology standard (ISO 10536). ISO 10536 cards must either be inserted into a slot or placed on the surface of the reader. This standard has not been accepted by industry and, at this date, is not common to use this technology because it has disadvantages such as:
- No chip manufacturer currently produces the electronic circuit required for the cards;
- The technology is not being used in the open market to any significant extent;
- The card and reader require precise alignment in order to function, making it less user-friendly than other contactless technologies.
The ISO/IEC 14443 proximity card technology has been used for the overwhelming majority of contactless card deployments. The targeted range of operations for this standard is from 0 to 10 cm, although this range varies, depending on power requirements, memory size, CPU, and co-processor. ISO 14443-2 allows for two types of interfaces, referred to as Type A and Type B.
The ISO 14443 Type A and Type B interfaces were originated as complementary technologies. Type A began with memory cards only. Type B was originally developed as the microprocessor alternative to Type A.
Proximity cards, or prox cards, are read-only devices that are encoded once and then used to transmit a fixed numeric value to a reader. The underlying mechanism is a radio frequency identification (RFID) token, which is embedded in an ID card.
The cards contain a chip and an antenna which, when brought within the geographic vicinity of a reader’s radio field, enables the card to draw power from the reader to communicate. Though the term can describe other variances of card technology, the typical prox card uses the 125 kHz frequency band. Prox cards are reasonably resistant to counterfeiting, but they do little to protect the data held by the card.
The ISO/IEC 15693 vicinity card technology (ISO 15693) was developed in response to the industry’s desire for a contactless card technology with an operational range greater than 10 cm. The vicinity card has three modes of operation: read mode, authenticate mode, and write mode. The maximum stated ranges are 70 cm for read mode, 50 cm for authenticate mode, and 35 cm for write mode.
ISO 15693 allows cards to operate at longer distances than ISO 14443 cards. The ISO 15693 standard was originally envisioned as a fare collection tool for longer ranges and/or an inventory control tag.
For fare collection, users would actively present the card as they entered a bus or train and be reidentified as they passed though a large read field on an exit door. Users would not need to present the card, as it could be read from a pocket, wallet, or purse. However, it is still uncertain what, if any, security problems are introduced by the longer communication distances.