Chip cards (“Smart Cards”) are special plastic cards with a built-in
integrated circuit (chip) that contains hardware logic, a memory or a microprocessor. Chip cards are controlled by special chip card readers.

Chip cards are differentiated according to various criteria. The most common distinction is made between memory chip cards with simple logic and processor chip cards with their own card operating system and cryptographic capabilities (which is why processor chip cards are also traditionally used in the PKI environment).

Chip cards are also differentiated from the outside through the interface. The contact-based chip cards are opposed to the contactless RFID chip cards. Chip cards with several (different) chips are called hybrid cards.

The most important component of the chip card is the integrated circuit, which determines the capabilities and thus the field of application of the chip card.

The card dimensions are standardized, three different sizes are available. The most commonly used are the credit card format (ID-1 / SIM / 1FF) and - mainly in mobile telephony - the mini-SIM card (ID-000 / Mini-SIM / 2FF). Smart cards can also be in the form of USB tokens