Patent ID: 8364808

Claim:
A device management system for managing a device based on management information contained therein, comprising: a device monitoring unit comprising a first processor and configured to possess a first key for encryption and to obtain management information from a device; a relay server comprising a second processor and configured to be coupled to the device monitoring unit over a network and to possess a second key used for decryption that is paired with the first key; and a management server, comprising a third processor and coupled to the relay server over a network configured to manage the device based on the management information, wherein the device monitoring unit obtains the management information from the device, calculates a hash value based on the obtained management information, assigns a packet number in sequence encrypts the hash value and the packet number by the first key encapsulates the obtained management information, the encrypted hash value and the encrypted packet number in data packets and transmits the data packets to the relay server the obtained management information encapsulated in the data packets is unencrypted, upon receiving the data packet, the relay server decrypts the encrypted hash value and the encrypted packet number in each data packet by the second key and determines whether or not the received management information has been tampered with based on the decrypted hash value and the decrypted packet number, and if it is determined that the management information has not been tampered with based on the decrypted hash value and the decrypted packet number, the relay server encrypts and transmits to the management server the management information.