Patent ID: 7849304

Claim:
An on-line diagnostics system comprising one or more pieces of industrial equipment for performing specific processes, and a maintenance apparatus for maintaining the industrial equipment, which are connected via the Internet, wherein the industrial equipment comprises an encryption unit for encrypting equipment information indicating the state of the industrial equipment, using a specific common key; a communication unit for transmitting the encrypted equipment information encrypted by the encryption unit to the maintenance apparatus in response to a request therefrom, and transmitting the common key used in encrypting the equipment information to the maintenance apparatus that received the encrypted equipment information, in response to a request therefrom; and an input/output unit for outputting all or part of the history of transmission of the common key from the industrial equipment to the maintenance apparatus, the maintenance apparatus comprises: a communication unit for receiving the encrypted equipment information transmitted by the communication unit of the industrial equipment and for receiving the common key used in encrypting the equipment information from the industrial equipment after requesting it therefrom; a decryption unit for storing the common key received by the communication unit of the maintenance apparatus and for decrypting the encrypted equipment information using the stored common key; and an input/output unit for storing the equipment information decrypted by the decryption unit and for outputting all or part of the stored equipment information; and wherein the communication unit of the industrial equipment carries attribute information indicating the attributes of the user of the maintenance apparatus, and condition information indicating a condition concerning the attributes of the user of the maintenance apparatus that is required when transmitting the common key, wherein, when the common key is requested by the maintenance apparatus, the communication unit reads the attribute information about the user and the condition information about the common key, and transmits the common key to the maintenance apparatus only when the attributes in the attribute information that has been read satisfy the condition in the condition information that has been read.