Introduction - RFID: Fundamentals and Applications in Contactless Smart Cards and Identification - page 5

1.1.4 Smart cards

A smart card is an electronic data storage system, possibly with additional computing
capacity (microprocessor card), which — for convenience — is incorporated into a
plastic card the size of a credit card. The first smart cards in the form of prepaid
telephone smart cards were launched in 1984. Smart cards are placed in a reader,
which makes a galvanic connection to the contact surfaces of the smart card using
contact springs. The smart card is supplied with energy and a clock pulse from the
reader via the contact surfaces. Data transfer between the reader and the card takes
place using a bidirectional serial interface (I/O port). It is possible to differentiate
between two basic types of smart card based upon their internal functionality: the
memory card and the microprocessor card.
One of the primary advantages of the smart card is the fact that the data stored
on it can be protected against undesired (read) access and manipulation. Smart cards
make all services that relate to information or financial transactions simpler, safer and
cheaper. For this reason, 200million smart cards were issued worldwide in 1992. In
1995 this figure had risen to 600million, of which 500million were memory cards and
100million were microprocessor cards. The smart card market therefore represents
one of the fastest growing subsectors of the microelectronics industry.
One disadvantage of contact-based smart cards is the vulnerability of the contacts
to wear, corrosion and dirt. Readers that are used frequently are expensive to maintain
due to their tendency to malfunction. In addition, readers that are accessible to the
public (telephone boxes) cannot be protected against vandalism.

1.1.4.1 Memory cards

In memory cards the memory — usually an EEPROM — is accessed using a sequen-
tial logic (state machine) (Figure 1.5). It is also possible to incorporate simple security
algorithms, e.g. stream ciphering, using this system. The functionality of the memory
card in question is usually optimised for a specific application. Flexibility of applica-
tion is highly limited but, on the positive side, memory cards are very cost effective.
For this reason, memory cards are predominantly used in price sensitive, large-scale

Address and
Security Logic

Vcc GND

RST Vpp

CLK I/O EEPROM ROM

Figure 1.5 Typical architecture of a memory card with security logic