Abstract: Rights information concerning contents required by a user terminal and these contents are delivered via a data communication network from a contents provider having a contents delivery server. The user terminal overwrites rights information stored in an information memory within or attached to the terminal with rights information that is newly delivered from the contents delivery server. A variety of contents services are provided to users free of charge or at discounted rates on the condition that rights information is overwritten in this manner.

Abstract: A recording medium and copy apparatus reduce user confusion when copying digital data recorded on a recording medium by notifying the user in advance of copy control information embedded in the digital data as a watermark or the like.

Abstract: A recording medium 100 having recorded digital data includes a content data storage region 10, a reproduction control information storage region 20 having a parameter for determining a reproduction frequency at random reproduction, and an index storage region 30. The reproduction control information in the reproduction control storage region 20 is updatable. Therefore, the reproduction control information helps the reproduction frequency to change at reproduction if utilized for determining the reproduction frequency in a data recording and reproducing device.