Signal transmission confidentiality

Safety protection measures taken to prevent leakage of secrets during the transmission of communication signals.

The security of signal transmission is mainly to ensure that the signal is neither leaked, altered, or destroyed during transmission, nor is it identified and controlled by illegal systems. It is an important link to ensure the integrity, confidentiality, availability, controllability and certainty of communication information.

Signal transmission security includes: ①Signal concealment. The special measures taken to transmit the signal are aimed at concealing the true content of the information and preventing the other party and unrelated persons from knowing the signal transmission method. ② Channel confidentiality. Channels are channels for signal transmission, including cables, optical fiber communications, wireless communications (including satellite communications), etc. Channels are easily intercepted, and channel secrecy mainly depends on password secrecy.

The main methods of stealing secrets in the signal transmission process are: ① wiretapping. Refers to connecting an unauthorized device (such as a computer terminal) to a communication line to obtain access to data by generating error messages or control signals, or by changing the communication method of a legitimate user. In a computer network system, information communication between network nodes or workstations is often carried out by broadcasting, and the signal transmission does not specify a specific direction. All nodes or workstations on the network can receive the signal. Under normal circumstances, only the information receiver can respond to the signal and receive the information, but if a computer with special software is connected to a node interface or workstation interface on the Internet, the password can be intercepted and the information can be intercepted. Wiretapping can intercept all information transmitted on the line, including various data and image information. If it is voice information, it can be heard directly; if it is other information, it needs to be demodulated. ②Electromagnetic leakage. Refers to the stray (parasitic) electromagnetic energy of computer systems and network system equipment, transmission lines, etc., spreading outward through wires or spaces. The radiated electromagnetic radiation signal carrying computer information can be received within a certain range with the aid of instruments and equipment, after extraction processing, deciphering and restoring, and restoring the original information, resulting in information loss of confidentiality. There are two main ways for computer electromagnetic leakage: the device emits electromagnetic radiation signals into the air by radiation; and the signal transmission is lost by conduction in the signal transmission process.

The main measures for signal transmission confidentiality include: ①Encryption technology. To ensure that the signal is not stolen during transmission, the most effective way is to encrypt the transmitted information so that even if the thief intercepts the signal, he cannot know the true content of the signal. Encryption technology belongs to signal concealment technology. The core of encryption technology is cryptography. Enhancing the level of signal confidentiality by means of ciphering. ② Private network technology. A technology that connects some important or highly confidential computer equipment using dedicated lines. Private network technology belongs to channel secrecy technology, which is a relatively effective technology to deal with wiretapping. If the private network line can use underground cables or optical fiber cables, the security strength will be higher. Especially the optical fiber cable overcomes the problem of electromagnetic radiation or wire interception, and is a modern communication transmission line with high confidentiality performance. ③Integrity protection technology. To verify the correctness of information exchange in the system or network, to protect the transmitted information from unauthorized tampering, deletion, replay or delay, and to prevent active attacks and interference such as intentional modification of information. It is a signal transmission An important measure of confidentiality.

Publisher: China Military Encyclopedia Editing Room