Communication system with function of encryption/decryption by agency

摘要

An agency communication section is equipped in an intranet, and when communications are made with a slave unit on the Internet which is located outside a firewall, the agency communication section executes encryption/decryption by agency in place of a slave unit having no mechanism for encryption in the intranet. The slave unit having a mechanism for encryption judges whether it is located inside or outside the firewall, and executes encryption if it is located outside or executes no encryption if it is located inside.