Controls, industrial control systems and cryptographic key life extension methods

摘要

PROBLEM TO BE SOLVED: To provide a distributed control device having improved security performance and reliability. SOLUTION: A control device 1 configured to communicate with another control device via a communication network transmits an encryption key having a life period for performing encrypted communication with the other control device via the communication network. A key acquisition unit 2 configured to acquire from a key distribution server, an encrypted communication unit 3 configured to execute encrypted communication with another device using an encryption key within the life period, and a key acquisition unit. Executes the server state detection unit 4 configured to detect the key acquisition impossible state, which is the state in which the encryption key cannot be acquired by the unit, and the extension process for extending the life period when the key acquisition impossible state is detected. A life extension portion 5 configured as described above is provided. [Selection diagram] Fig. 2