To limit a position where a printer 30 can be used.
At the time of installation of the printer 30, the printer generates a secret key by public key cryptography with the use of a pass phrase including at least printer position information. At the same time, the printer 30 holds this secret key and destroys a public key. Every time a printing client 20 is to request printing, he or she requests the public key to the printer 30. The printer 30 receiving the request generates the public key by public key cryptography with the use of the pass phrase including at least the printer position information at the time point, and transmits the public key to the printing client 20. At the printing client 20, printing data is encoded by the public key and is transmitted as encoded printing data to the printer 30. At the printer 30, the encoded printing data is decoded by the held secret key. Printing based on the printing data is carried out when the encoded printing data can be decoded, whereas printing is not carried out when the encoded printing data cannot be decoded.
SHIMA TOSHIHIRO
KOJIMA TERUHITO
Hidetoshi Tachibana
Yasukazu Sato
Hiroshi Yoshimoto
Yasushi Kawasaki
Takeshi Sekine