There are three different types of embedded information, which have different characteristics: If digital signature configuration is used, the receiver can detect the first information, because the attacker will not be able to create the correct signature that only the authorized sender has. The detection of the second and third messages is more difficult because they only send correct and effective messages at the wrong time. For example, an attacker sends a Scenario 2 attack, capturing and saving valid data packets in the last operation, including the command to open the circuit breaker. If the signature information or payload data contains a serial number, the receiver will prevent the implantation of the second type of information. The replay information does not have the correct sequence number, so it will be detected and discarded. Ensure that the serial number range is large enough to wait for the range to overflow and cycle the last unavailable serial number. In particular, it is pointed out that the serial number range cannot be a multiple of the period of an information sequence. After information is lost, the system needs to be allowed to skip some serial numbers to complete synchronization, and the serial number window that meets the requirements in the future should be limited, otherwise the system will be vulnerable to replay attacks after the first serial number overflows. The time stamp parameter of precise interval scale (the marking time is less than the minimum possible distance between two valid messages) can also be used as the sequence number. The delay valid information (third information) cannot be directly recognized by the receiver. The detection of delay information is based on the detection of information that did not arrive at the initial time. This protocol will be described in the next section. The delay is less than the detection threshold of information suppression, and the protocol cannot be recognized by the receiver. Therefore, the system should be designed in the application layer, and the information delay is within the suppression detection time, so the system will not cause any loss.

Supplementary question: Ensure that passwords are fully protected, prevent private passwords from being leaked, prevent public passwords from being modified, and save them in devices connected to the network. It is important that each device cannot use its factory-set password, but should set a password for each independent automatic operating system when configuring. Digital signatures and possible encryption passwords should be clearly assigned, and it is best to use out-of-band channels when configuring the system. For example, manually install a handheld password generator device. Using automatic password exchange is very dangerous because of omitting' man-in-the-middle attack' and out-of-band confirmation. By using the above-mentioned protocol transcoding instead of digital signature transcoding based on asymmetric password, symmetric password with secret password can be used. In this way, it is necessary to establish a secret password and assign it to each transmitter-receiver pair.

Note: As I am not an electrical major, there will inevitably be mistakes in the translation process. Please modify it yourself.