Smart card chips contain a microprocessor and/or memory. They are embedded in smart cards; portable devices that resemble credit cards but are used in applications such as banking and health care. Although the term “smart card” is used to describe any card that can relate information to an application, passive devices such as magnetic stripe cards, optical cards, and memory cards can only store information or complete pre-defined operations. By contrast, smart cards with embedded microprocessors contain all of the information and functions needed to complete transactions. Known as “chip cards”, these microprocessor-based devices do not require access to remote databases and can perform a dynamic series of complex calculations. Although smart card chips that include both a microprocessor and memory offer the greatest degree of versatility, the majority of smart cards are memory-only devices.
Types of Smart Card Chips
There are three basic types of smart card chips. Contact chips are read by an independent card reader and conform to ISO 7816, the International Standards Organization (ISO) specification for the standardization of smart card systems. Contactless chips are read by radio frequency (RF) signals instead of a card reader. They conform to ISO 14443A and include a magnetic loop antenna that operates at 13.56 MHz. Combi cards are plastic smart cards with a central processing unit (CPU), chip operating system (COS), security module and embedded memory. They incorporate both contact and contactless functions.
Microprocessor Architecture and Interfaces
There are several microprocessor architectures and interfaces for smart card chips. Typically, older cards are based on relatively slow, 8-bit embedded microcontrollers. Newer smart card chips feature 12-bit, 16-bit, 32-bit or 64-bit microprocessors. Universal serial bus (USB) is a 4-wire, 12-Mbps serial interface for low-to-medium speed peripheral device connections to personal computers (PC). PCMCIA devices or PC cards are credit card-sized peripherals used mainly in laptop and notebook computers. They plug into a 68-pin host socket that is connected either to the motherboard or an expansion bus. Inter-IC (I2C) is a multi-master interface that allows multiple chips to be connected to the same bus with each chip acting as a master by initiating a data transfer.
Selecting Smart Card Chips
Selecting smart card chips requires an analysis of available features. Data encryption standard (DES) is a popular, symmetric encryption system in which the sender and receiver of a message share a single, common key that is used to encrypt and decrypt the message. Triple DES (3DES, TDES) is a DES encryption algorithm that encrypts data three times for added security. Smart card chips that use advanced encryption standard (AES) and elliptic curve cryptography are also available. Some devices include anti-intrusion security or a unique chip identification number. Others provide electrostatic discharge (ESD) protection or cyclic redundancy check (CRC) algorithms.
Integrated Circuit (IC) Packages
Smart card chips are available in a variety of integrated circuit (IC) packages and with different number of pins. Basic IC package types include ball-grid array (BGA), quad flat package (QFP), single in-line package (SIP) and dual in-line package (DIP). BGA variants include plastic ball-grid array (BGA), tape ball-grid array (TBGA), and super ball-grid array (SBGA). Fine-pitch land-grid array (FLGA) packages are also available. Common QFP variants include low quad flat package (LQFP) and very thin quad flat package (VQFP). DIPs are available in either ceramic (CDIP) or plastic (PDIP). Other IC package types for smart card chips include small outline package (SOP), small outline integrated circuit (SOIC), thin small outline package (TSOP), thin very small outline package (TVSOP), small outline J-lead (SOJ), shrink dual in-line package (SDIP), and shrink zigzag in-line package (SZIP).