The present invention relates to the technical field of power data protection, and discloses a data communication
system for distribution network protection based on the SM1 national cryptographic
algorithm. An identity
authentication protocol request is sent to a security
machine through an identity
library switch, and a reply protocol for responding to the identity
authentication protocol request from the security
machine is received. It is verified whether the reply protocol is correct. If the
verification of the reply protocol is correct, the communication blocking states between the external distribution network protection device and the
encryption switch are respectively released, so as to obtain the service data in the external distribution network protection device. An identity
key authentication is also performed with the
encryption switch through the SM1 national cryptographic
algorithm. If the
authentication is successful, the service data is forwarded to the
encryption switch, and the MAC of the protection terminal is bound through the encryption switch, excluding the possibility of illegal devices accessing the
authenticated encryption switch, thereby improving the identity authentication security performance of the communication
system, reducing the difficulty of deployment, installation and maintenance, and at the same time, improving the security of data communication transmission.