A system is provided which manages the copyright of a plurality of data in a database. A data copyright management system is provided in which a primary user edits data which he or she obtains and supplies edited data to a secondary user. In a case where new data is produced by editing a plurality of encrypted data obtained from the database, and is encrypted for distribution to another person, crypt keys for a plurality of data as raw material and an edit program which is an editing process with a digital signature are used as a use permit key. When a user who receives the edited and encrypted data requests use of the data by presenting the digital signature to a copyright management center, the copyright management center identifies the editor by the digital signature, and provides the user requiring use of data with the crypt key for use only when the editor is identified to be the valid user of the edited data. The system comprises a database and a key control center, and uses a primary copyright label, a first use permit key including a first crypt key, a second use permit key, a third crypt key, and a copyright management program. The primary user uses primary copyrighted data encrypted by using the first crypt key and supplied, by decrypting it with the first use permit key obtained from the key control center. The data is encrypted again by using the first use permit key when it is stored. The primary user edits the primary copyrighted data by obtaining a second use permit key from the key control center for editing the primary copyrighted data. The data being edited is encrypted and stored by using the second use permit key. At the completion of the editing, the primary user receives the third crypt key for secondary copyright as secondary exploitation right, encrypts the edited data with the third crypt key, and distributes it to a secondary user. The secondary user obtains the third crypt key and uses the edited data. In another system, in a case where a new data is produced by editing a plurality of data obtained from the database, and encrypted for distribution to another person, crypt keys for a plurality of data as raw material and an edit program which is an editing process with a digital signature are used as a use permit key. When a user who receives the edited and encrypted data requests use of the data by presenting the digital signature to a copyright management center, the copyright management center identifies the editor by the digital signature, and provides the user requiring data use with a crypt key for use only when the editor is identified to be the valid user of the edited data.