Patent ID: 7506159

Claim:
A printer which executes a print operation based on print data, comprising: a first printer position information acquisition unit which acquires printer position information to specify a place where the printer is installed, this printer position information being regarded as first printer position information; a public key generator which generates a public key with a passphrase containing at least the first printer position information; a public key transmitter which transmits the public key to a print client in response to a request from the print client; an encrypted common key receiver which receives an encrypted common key generated by encrypting a common key with the public key from the print client; an encrypted print data receiver which receives encrypted print data generated by encrypting print data with the common key from the print client; a second printer position information acquisition unit which acquires printer position information to specify a place where the printer is installed, this printer position information being regarded as second printer position information; a private key generator which generates a private key with a passphrase containing at least the second printer position information; a common key acquisition unit which decrypts the encrypted common key received by the encrypted common key receiver with the private key to acquire the common key; a print data acquisition unit which decrypts the encrypted print data with the common key acquired by the common key acquisition to acquire the print data; and a public key holder which holds the public key generated by the public key generator, wherein the public key transmitter acquires the public key held by the public key holder and transmits this public key to the print client.