Abstract: A data authenticity assurance method carried out by a management computer including: a first step of receiving the first data piece from the computer; a second step of selecting a plurality of second data pieces at predetermined intervals in chronological order from among the plurality of second data pieces held in the data holding part; a third step of performing an arithmetic operation for each of the hash values of the selected plurality of second data pieces; a fourth step of generating signature target data by combining the first data piece received from the computer with the hash values of the selected plurality of second data pieces; and a fifth step of generating a second data piece by assigning the digital signature to the signature target data by using the preset key, and holding the generated second data piece in chronological order sequentially in the data holding part.

Abstract: A data authenticity assurance method carried out by a management computer including: a first step of receiving the first data piece from the computer; a second step of selecting a plurality of second data pieces at predetermined intervals in chronological order from among the plurality of second data pieces held in the data holding part; a third step of performing an arithmetic operation for each of the hash values of the selected plurality of second data pieces; a fourth step of generating signature target data by combining the first data piece received from the computer with the hash values of the selected plurality of second data pieces; and a fifth step of generating a second data piece by assigning the digital signature to the signature target data by using the preset key, and holding the generated second data piece in chronological order sequentially in the data holding part.

Abstract: Method and apparatus for totally managing sets of construction-related information relating to constructional relationship between each product to be produced and its component parts, and sets of production-related information relating to production of the products, wherein the sets of construction- and production-related information are determined as respective subjects which can be similarly processed and which are classified into classes on the basis of extracted mutual relationships of the subjects, and a set of subject data incorporating mutually related sets of element data including subject substance data and relationship substance data which indicate substances of each subject and the relationships is stored by a data storing device operated by a user, in a production information memory from which the set of subject data is retrieved and outputted by an output device.