Patent ID: 7673334

Claim:
A communication system comprising: a first communication device; a second communication device which communicates with the first communication device; and a security assurance device which assures security during communication between the first communication device and the second communication device, wherein: the second communication device transmits notification information for notifying a security level of the second communication device during communication to the security assurance device; the security assurance device receives the notification information via a control section, stores the notification information in a memory device, verifies the security level of the second communication device in a server authentication section during communication based upon the notification information, and, if the security level of the second communication device is confirmed, generates security assurance information which proves the security level of the second communication device during communication and transmits it to the second communication device; the second communication device receives the security assurance information, and transmits the security assurance information to the first communication device according to a connection request from the first communication device; and the first communication device, after the connection request to the second communication device, receives the security assurance information from the second communication device, and verifies the security level of the second communication device during communication with the second communication device based upon the security assurance information.