Patent ID: 7594118

Claim:
A data-processing device comprising: a holding unit arranged to hold first private-key information; an inputting unit arranged to input second private-key information; a private-key-information generating unit arranged to generate third private-key information based on the first private-key information and the second private-key information, and store the third private-key information; a signature-information generating unit arranged to generate signature information based on information to be verified and the third private-key information; an outputting unit arranged to output the information to be verified and the signature information; a database arranged to hold the first private-key information held in the hold unit provided in the data-processing device for registration; a unit arranged to acquire the first private-key information for the data-processing device for registration by referring to the database, where a registration request is transmitted via a network, generate the second private-key information according to a predetermined algorithm, and generate public-key information that corresponds to the third private-key information generated based on the first private-key information and the second private-key information; and a transmission unit arranged to transmit the generated second private-key information and public-key information to a request source.