A smart card, chip card, or integrated circuit card (ICC), is in any pocket-sized card with embedded integrated circuits which can process data. This implies that it can receive input which is processed — by way of the ICC applications — and delivered as an output. There are two broad categories of ICCs. Memory cards contain only non-volatile memory storage components, and perhaps some specific security logic. Microprocessor cards contain volatile memory and microprocessor components. The card is made of plastic, generally PVC, but sometimes ABS. The card may embed a hologram to avoid counterfeiting. Using smartcards also is a form of strong security authentication for single sign-on within large companies and organizations.

Contact smart cards have a contact area, comprising several gold-plated contact pads, that is about 1cm square. When inserted into a reader, the chip makes contact with electrical connectors that can read information from the chip and write information back.

• the physical shape
• the positions and shapes of the electrical connectors
• the electrical characteristics
• the communications protocols, that includes the format of the commands sent to the card and the responses returned by the card.
• robustness of the card
• the functionality

The cards do not contain batteries; energy is supplied by the card reader.

A second type is the contactless smart card, in which the chip communicates with the card reader through RFID induction technology (at data rates of 106 to 848 kbit/s). These cards require only close proximity to an antenna to complete transaction. They are often used when transactions must be processed quickly or hands-free, such as on mass transit systems, where smart cards can be used without even removing them from a wallet.