Smart cards are classified according to inlaid chips, which can be roughly divided into 5 categories, as follows:
1. memory card
The chip in cards is EEPROM (Electrically Erasable Programmable Read-onlyMemory)，and address decoding circuit and instruction decoding circuit. In order to encapsulate it in a 0.76mm plastic card base, it is specially made into a 0.3mm thin structure. Memory cards are passive cards and usually use synchronous communication. This card is convenient to store, simple to use, and inexpensive, and can replace magnetic cards in many occasions. However, this type of IC card does not have a security function, so it is generally used to store information that does not need to be kept confidential. For example, first aid card for medical use, customer menu card for catering industry. Common memory cards include AT24C16 and AT24C64 from ATMEL.
2. Logical encryption card
In addition to the EEPROM of the memory card, this type of card also has encryption logic, which requires password verification before each reading/writing of the card. If the password is incorrectly verified several times in a row, the card will be self-locked and become a dead card. In terms of data management, password verification and identification, the logical encryption card is also a passive card, which communicates in a synchronous manner. This type of card has relatively small storage capacity and relatively cheap price, and is suitable for occasions with certain confidentiality requirements, such as canteen dining cards, telephone cards, and public utility charge cards. Common logic encryption cards include SLE4442 and SLE4428 from SIEMENS, and AT88SC1608 from ATMEL.
The internal storage space of the 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 chip manufacturer, IC card manufacturer, IC card issuer and other code data, which is used to identify and track information about manufacturers and applications of users, providing the possibility of enhancing security in management;
B). Personalization area: this is the area related to the application. Relevant data in this area controls the personalization process of the card and provides security guarantee for the personalization operation, such as the limit on the number of times of use and the limit on repeated use;
C). Security zone: used to store unreadable relevant security data, such as personal password, etc.;
D). Application area: used to store application data information.
3. CPU card
This type of chip contains a microprocessor unit (CPU), a storage unit (RAM, ROM and EEPROM), and an input/output interface unit. Among them, the RAM is used to store the intermediate data in the operation process, the ROM is solidified with an on-chip operating system COS (Chip Operating System), and the EEPROM is used to store the personal information of the cardholder and the relevant information of the issuing unit. The CPU manages the encryption/decryption and transmission of information, and strictly prevents illegal access to the information in the card. If several illegal accesses are found, the corresponding information area will be locked (the higher-level command can also be used to unlock it). The capacity of the CPU card is large or small, and the price is higher than that of the logic encryption card. But the good processing ability and excellent security performance of CPU card make it become the main direction of IC card development. CPU cards are suitable for occasions with particularly high confidentiality requirements, such as financial cards, military secret order transfer cards, etc. The famous CPU card providers in the world are Gemalto, G&D, Schlumberger and so on.
4. Super smart card
On the basis of the CPU card, adding a keyboard, a liquid crystal display, and a power supply becomes a super smart card, and some cards also have a fingerprint identification device. A super card tested by the VISA international credit card organization has 20 keys and can display 16 characters. In addition to the functions of timekeeping and computer exchange rate conversion, it also stores personal information, medical and travel data and telephone numbers.
The last type of smart card is the optical card. In 1981, a company in the United States put forward the concept of optical card, thus rich card type data storage. Optical cards are composed of semiconductor laser materials that can store records and regenerate large amounts of information. There are two optical card recording patterns: Canon and Delta. Both forms have been accepted as international standards by the International Organization for Standardization. Optical card has the advantages of small size, easy to carry, safe and reliable data, large capacity, strong anti-interference, not easy to change, good confidentiality and relatively cheap price.
——This article is excerpted from 21IC.com