| 摘要 |
PROBLEM TO BE SOLVED: To improve security of communication while reducing a burden on a user.SOLUTION: A facility management device 3A, 3B generates, by using a first secret key, a root certificate to be used for encryption communication between the facility management device 3A, 3B and a monitoring terminal 4A, 4B, when a first start condition is satisfied; and generates, by using a second secret key, a server certificate to be used for the encryption communication, when a second start condition is satisfied. The facility management device 3A, 3B, when having received a request to start the encryption communication from the monitoring terminal 4A, 4B, transmits the server certificate and a first public key corresponding to the first secret key to the monitoring terminal 4A, 4B. The facility management device 3A, 3B receives, from the monitoring terminal 4A, 4B, an encrypted common key obtained by using a second public key corresponding to the second secret key; decrypts, by using the second secret key, the encrypted common key; and, when having received a command encrypted using the common key from the monitoring terminal 4A, 4B, decrypts the command by using the decrypted common key.SELECTED DRAWING: Figure 1 |
