Information security mainly involves three aspects: the security of information transmission, the security of information storage, and the audit of the content of network transmission information.

Authentication

Authentication is the process of verifying the subject in the network. There are usually three methods to verify the identity of the subject. The first is secrets that only the subject knows, such as passwords and keys; the second is the items carried by the subject, such as smart cards and token cards; the third is unique characteristics or abilities that only the subject has, such as fingerprints, voices, retinas or signatures. wait.

Password mechanism: The password is a mutually agreed code, which is assumed to be known only by the user and the system. Passwords are sometimes chosen by the user and sometimes assigned by the system. Normally, the user first enters some kind of identification information, such as a user name and ID number, and then the system asks the user for a password. If the password matches the one in the user file, the user can access. There are many kinds of passwords, such as one-time passwords. The system generates a list of one-time passwords. X must be used for the first time, Y must be used for the second time, Z must be used for the third time, and so on; there are also time-based passwords. The password, the correct password for access, changes over time, based on time and a secret user key. This way the password changes every minute, making it harder to guess.

Smart card: Access requires not only a password, but also a physical smart card. Check whether it is allowed access to the system before allowing it into the system. A smart card is about the size of a credit card and generally consists of a microprocessor, memory, and input and output facilities. The microprocessor calculates a unique number (ID) for the card and an encrypted form of other data. The ID guarantees the authenticity of the card and gives the cardholder access to the system. To prevent smart cards from being lost or stolen, many systems require both the card and an identification number (PIN) to be used together. If you only have the card but do not know the PIN code, you will not be able to enter the system. Smart cards are better than traditional password methods for identification, but they are inconvenient to carry and account opening costs are high.

Subject characteristic identification: The method of using personal characteristics for identification is highly secure. Existing equipment includes: retinal scanners, voice verification equipment, and hand recognition devices.

Data transmission security system

Data transmission encryption technology aims to encrypt the data stream during transmission to prevent eavesdropping, leakage, tampering and destruction on the communication line. If distinguished by the communication level implemented by encryption, encryption can be implemented at three different levels of communication, namely link encryption (encryption located below the OSI network layer), node encryption, and end-to-end encryption (encrypting files before transmission, Encryption that lies above the OSI network layer).

The two most commonly used methods are link encryption and end-to-end encryption. Link encryption focuses on the communication link without considering the source and sink. It uses different encryption keys to provide security protection for confidential information through each link. Link encryption is node-oriented and is transparent to the high-level network subjects. It encrypts all high-level protocol information (address, error detection, frame header and frame tail), so the data is ciphertext during transmission, but at the central node The routing information must be decrypted. End-to-end encryption means that the information is automatically encrypted by the sending end and enters the TCP/IP packet return, and then passes through the Internet as unreadable and unrecognizable data. Once the information reaches the destination, it will be automatically reorganized and decrypted. become readable data. End-to-end encryption is oriented to high-level network entities. It does not encrypt information on lower-layer protocols. The protocol information is transmitted in plain text, and user data does not need to be decrypted at the central node.

Data integrity authentication technology At present, for dynamically transmitted information