Smart cards can be classified into five categories based on embedded chips, as follows:

1. Storage card

The chip inside the card is an electrically erasable programmable read-only memory (EEPROM), as well as address decoding circuits and instruction decoding circuits. In order to encapsulate it in a 0.76mm plastic card base, a thin structure of 0.3mm has been specially designed. Memory cards belong to passive cards and usually use synchronous communication methods. This type of card is convenient to store, easy to use, and inexpensive, and can replace magnetic cards in many situations. But this type of IC card does not have confidentiality function, so it is generally used to store information that does not need to be kept confidential. For example, emergency cards and customer menu cards used in the catering industry. Common memory cards include AT24C16 and AT24C64 from ATMEL company.

2. Logical encryption card

In addition to the EEPROM of the storage card, this type of card also has encryption logic, and password verification must be performed before reading/writing the card each time. If the password verification is incorrect several times in a row, the card will lock itself and become a dead card. In terms of data management, password verification, and identification, logical encryption cards are also passive cards that communicate synchronously. This type of card has a relatively small storage capacity and is relatively inexpensive. It is suitable for occasions with certain confidentiality requirements, such as cafeteria dining cards, telephone cards, and public utility fee cards. Common logical encryption cards include SLE4442 and SLE4428 from SIEMENS, and AT88SC1608 from ATMEL.

The internal storage space of a logical encryption card can usually be divided into the following four functional areas according to different application needs:

a) Manufacturer code area: This area stores unchangeable code data for chip manufacturers, IC card manufacturers, and IC card issuers. This data is used to identify and track information about manufacturers and user applications, providing the possibility to enhance security in management;

b) Personalized area: This is an area related to the application, where the relevant data controls the personalization process of the card and provides security guarantees for personalized operations, such as usage limits, reuse limits, etc;

c) Security zone: used to store unreadable security related data, such as personal passwords, etc;

d) Application area: used to store information about application data.

3. CPU card

This type of chip contains a microprocessor unit (CPU), storage units (RAM, ROM, and EEPROM), and input/output interface units. Among them, RAM is used to store intermediate data during the calculation process, ROM has a fixed on-chip operating system COS (Chip Operating System), and EEPROM is used to store personal information of cardholders and relevant information of issuing units. CPU manages the encryption/decryption and transmission of information, strictly preventing illegal access to card information. If multiple illegal accesses are found, the corresponding information area will be locked. The capacity of CPU cards varies, and their price is higher than that of logical encryption cards. However, the excellent processing capability and superior confidentiality performance of CPU cards have made them the main direction for the development of IC cards. CPU cards are suitable for situations with particularly high confidentiality requirements, such as financial cards, military secret transmission cards, etc. Internationally renowned CPU card providers include Gemalto, G&D, Schlumberger, and others.

4. Super smart card

By adding a keyboard, LCD display, and power supply to the CPU card, it becomes a super smart card, and some cards also have fingerprint recognition devices. The super card tested by VISA International Credit Card Organization has 20 health keys and can display 16 characters. In addition to timing and computer exchange rate conversion functions, it also stores personal information, travel data, and phone numbers.

5. Optical card

In 1981, an American company proposed the concept of optical cards, which enriched card based data storage methods. Optical cards are composed of semiconductor laser materials and are capable of storing and recording large amounts of information. The optical card recording pattern has formed two types: Canon type and Delta type. Both forms have been accepted as international standards by the International Organization for Standardization. Optical cards have the advantages of small size, easy portability, reliable data security, large capacity, strong anti-interference ability, not easy to change, good confidentiality, and relatively low price.