We usually divide security into three categories, namely functional security, physical security and information security. Functional safety is to realize the safety function of equipment and factory. The protected safety-related components must perform their functions correctly. When a fault or failure occurs, the equipment or system must still be in a safe state or enter a safe state. Physical safety is to reduce the damage caused by electric shock, fire, radiation, mechanical danger, chemical danger and other factors.
Information security refers to the protection of the hardware, software and database of the computer system with the help of computer technology and network technology, so that the system can operate normally and will not be destroyed, changed or leaked due to accidents or malicious factors, so that users can feel safe in the use of information. The purpose of information security is to protect the security of information stored and processed in the information processing system, and its basic attributes are: integrity, availability, confidentiality, controllability and reliability.