Patent ID: 7797532
Filing Date: 2010-09-14
Classification: G06F,H04L

Abstract:
1. A device authentication system, comprising: a terminal device which stores predetermined secret information; a device authentication server which stores said secret information and authenticates said terminal device; and a service server which offers services to said terminal device authenticated by said device authentication server, wherein said device authentication server authenticates said terminal device by checking that server-specific information generated by said device authentication server is correctly encrypted by said terminal device using said secret information, and said terminal device authenticates said device authentication server by checking that terminal-specific information generated by said terminal device and encrypted using said secret information is correctly decrypted by said device authentication server; either said terminal device or said device authentication server generates a session key following the authentication, encrypts said session key using said secret information, and transmits the encrypted session key to the other device so as to share said session key therebetween; said device authentication server, using said session key, encrypts certificate information for certifying that said terminal device has been authenticated and transmits the certificate information to said terminal device; said terminal device acquires said certificate information sent from said device authentication server by decrypting said encrypted certificate information using said session key, and transmits the acquired certificate information to said service server; said service server receives said certificate information from said terminal device and transmits the received certificate information to said device authentication server prompting said device authentication server to check that said certificate information is valid; said certificate information includes identification information with which said device authentication server identifies a result of the device authentication of said terminal device and encrypted identification information generated by encrypting said identification information using a server key specific to said device authentication server; and said device authentication server, using said server key, decrypts said certificate information received from said service server so as to acquire said encrypted identification information included in said certificate information, and determines whether said certificate information is valid by checking that the acquired identification information coincides with the identification information included in the received certificate information.