DEVICE MANAGEMENT SYSTEM, SITE MONITORING APPARATUS AND METHOD

A server certificate and root certificate for performing secure communication with monitoring target devices are issued in a site monitoring apparatus. Using a secret key that is paired with a public key, a digital signature is issued based on communication destination information in which the site monitoring apparatus is the communication destination and the issued root certificate, and the communication destination information, root certificate, and digital signature are transmitted to the monitoring target devices. The monitoring target devices receive the communication destination information, root certificate, and digital signature from the site monitoring apparatus. Authentication is performed on the received digital signature using the public key, and in accordance with successful authentication, the communication destination for device monitoring information is changed from a management server to the site monitoring apparatus and secure communication is performed with the site monitoring apparatus, using the received communication information and root certificate.