1 Introduction
The card system is an important embodiment of the school informationization work and an important application of digital campus construction. The one-card system can realize the campus “consumer cardâ€, “identity card†and “school management cardâ€, which makes the learning and life of the teachers and students of the school more convenient, faster and more efficient.
In a school, dining room dining, bathroom bathing, watering in the water room, shuttle bus, library borrowing books, access to and from the access control system, payment of network fees, paid use of sports facilities, school registration, etc. are all used in the card system. And with the change of people's concept, more and more application systems will be docked with the card system, and will be added to the card system, so that the card of the card completely replaces the student card, work permit, library card, shuttle certificate, registration card, canteen. Cards, access cards, etc., truly realize the "one card campus."
As the card system information, the card is the most basic and important equipment in the card system. The selection of the card and the safe design of the card are the key to the success of the card system.
2, card type
Today, cards are very versatile. Each person has several cards in their hands, such as medical cards, bus cards, bank cards, highway toll cards, shopping cards, shopping mall loyalty cards, canteen dining cards, campus cards, and so on.
Commonly used cards can be divided into magnetic cards and smart cards from the technology used by the cards.
The magnetic card has a magnetic strip on the back of each card, and information is stored in the magnetic strip. Due to the limitation of the storage space, only the account information is generally stored in the magnetic stripe, and the user detailed information and various usage records corresponding to the account are stored in the central database. At present, the savings cards and credit cards of the domestic banks use magnetic cards. Due to the limitations of the technology used, the information stored on the magnetic strip is easily lost when the magnetic card encounters magnetic fields, static electricity, distortion, scratches, and the like.
A smart card, also known as an integrated circuit card, is an integrated circuit card. It has the same shape as a magnetic card, except that there is no magnetic strip on the card, and an integrated circuit chip is embedded in the card. Depending on the integrated circuit embedded in the card, the smart cards can be divided into three categories: memory cards, logical encryption cards, and CPU cards.
The memory card is the integrated circuit in the card. It is a simple storage device with data storage function. It does not have data processing functions and hardware encryption functions, such as bus cards.
The logical encryption card is based on the memory card, and the encryption logic circuit protects the data in the card by verifying the password. However, it only has a simple security protection function, and is generally only applicable to one-time encryption. Card, like a phone stored value card.
The CPU card, that is, the integrated circuit in the card, includes a CPU, an EEPROM, a RAM, and an operating system COS (ChiPOperating System) that is solidified in the ROM. The CPU card not only has a data storage function, but also has functions such as command processing and data security protection. CPU cards are suitable for applications with high security requirements, such as campus cards and bank cards.
Because the smart card is safe, convenient, durable, and resistant to damage, and because the card reader of the magnetic card contains precision machinery and signal conversion devices, even ordinary magnetic card readers need several hundred dollars, and the card core of the smart card itself That is digital circuit, the card reader of the smart card only needs a card holder, and the simple smart card reader only needs more than ten yuan, so it is an inevitable trend that the smart card replaces the magnetic card, and with the advancement of technology, the card Capacity and security will be further strengthened, and the application of cards will become more and more extensive.
Depending on the form of card and external data transfer, smart cards can be divided into two categories: contact cards and contactless cards.
The contact card has eight contacts in the integrated circuit of the card that can be in contact with the outside world. The feature of the contact card is that the card must be inserted into the card reader to perform read and write operations, the card has a long read and write time, and the card is prone to wear.
The non-contact type card is also called an inductive type IC card or an RF card. The integrated circuit of the card has a radio frequency transceiver circuit and related circuits, and the card reader reads and writes the card into a non-contact type. The contactless smart card does not need to directly contact the card reader when reading and writing the card, and has a significant advantage over the contact card in terms of card reading time and card durability. The contactless card is a dominant card type for various applications in the future.
3, the characteristics of the card in the card system
The card system is a very large and complex application system with very high security requirements. Since the card system relies on the campus network, the card not only needs to store the cardholder's identity information, but also saves the cardholder's consumption balance and other financial information to ensure that the network failure occurs, the card reader device and the data center platform are interrupted. When you can't get the information of the database, read and write the consumption balance information directly on the card to ensure the normal use of the card. When the network is unblocked, upload the water flow information on the card reading device to the data center database to keep it. The card and library information are consistent. This requires that the card can be read and written in a card system, and the amount of information stored on the card should be large enough.
At present, the cards used in the card system are non-contact cards, and the mainstream uses MIFARE cards. MIFARE is a radio frequency smart card technology owned by PHILIPS. HILIPS does not manufacture cards or manufacture card readers. It only sells technology and chips, and other manufacturers produce or package cards. The typical model of the Mifare card is the Mifarel s50, which has the following features:
(1) High reliability, long service life, low maintenance cost, and adapt to various harsh environments. Under normal use, the service life of the card can be guaranteed for more than 10 years.
The EEPROM space of each card is 1K bytes.
(2) Each card is divided into 16 sectors, each sector has an independent password and access control policy, and the password uses the DES/HASWMD5 algorithm. Cards have tight logic and logical encryption.
(3) Each card has a unique serial number in the world.
(4) The data verification between the card and the card reader adopts the CRC method, and the two-way three-dimensional argumentation, the identity legality identification between the two before the data exchange, to ensure the security of the card.
(5) It is possible to process a plurality of cards that are overlapped at the same time.
4, the safety design of the card in the card system
In the card system, in order to ensure the security of the card, the following security measures are taken on the card:
(l) In order to prevent the occurrence of a fake card (ie, the appearance of the card and the card information is exactly the same as the card being forged), the serial number of Mifarelåž is used as the card number of the card system, and the card number is used as the sole main index of the system, To ensure the global uniqueness of each card, and for the cardholder to easily remember, an account is additionally set in the system, corresponding to the card number in the system.
(2) Adopt an encryption mechanism of “one card, one key, one sector and one key, one sector's key consisting of two sets of passwordsâ€, and adopt multiple encryption algorithms to prevent others from deciphering the card password and tampering with the card. Amount.
(3) Different information is placed in different sectors according to the frequency of use. For example, the identity information such as the amount information and the name are divided into different sectors, and the different application subsystems read-only and write the relevant sectors of the card, so that It can guarantee the reading and writing speed of the card, shorten the transaction time of each card, and prevent the card reading and error caused by the card holder taking the card in advance because the card operation time is too long. At the same time, data in one sector can be automatically migrated to other sectors to prevent the entire card from being used when one of the sectors is damaged.
(4) Some companies have also added their own company-specific logos to the cards, and adopted special algorithms to prevent other companies' card system from being used in their own card system.
(5) Classify and manage all the cards in the system, and assign different rights and functions to enhance the security management of the cards.
(6) For each card in the card system, the validity period is set. If the card exceeds the validity period, the card automatically enters the system blacklist, and each application subsystem will refuse to use the card in the blacklist. The lost card will also enter the blacklist to effectively protect the cardholder's interests.
(7) In order to minimize the economic loss of the cardholder, when the cardholder loses the card, the card loss can be reported in a variety of ways: voice phone self-service loss reporting, website self-service loss reporting, touch screen self-service loss reporting, self-service loss reporting, card self-service loss reporting, card The management center manually reported the loss.
(8) Set the first-level student as a batch. When the student graduates, the batch card will be reported lost, and the batch card number will be cleared from the lost library, which greatly reduces the number of dead cards that are not used in the system. .
5, the conclusion
The security of the card system and the security of the network environment, the security of the data center platform, the security of the application subsystem, the security of the data, the security of the bank transfer system, the security of the card, etc. are all closely related, and the security measures adopted in each link. Whether it is reasonable, any part of the security omission may lead to the cardholder's distrust of the system, resulting in hacker attacks on the system, and may even lead to the collapse of the entire system.
Among all the security factors, because the cards are distributed in the hands of tens of thousands of cardholders, and each application must use cards, and the card retains the cardholder's balance information, the card security is the most basic and most easily The link of the attack. Reasonable and thorough card security design is the key to the success of the card system.
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