The Internet user population has experienced explosive growth with the spread of broadband communication. This growth has caused the use of large amounts of high quality digital content to increase. Digital content has the characteristic that its quality does not deteriorate even if the content is duplicated, and digital content is also easy to handle. On the other hand, the fact that the quality does not deteriorate also introduces the risk that digital content can be easily duplicated illegally. Currently, RFID and QR codes are attracting attention as new technologies for data management. However, these technologies have a problem from the point of view of safety management, security, and their high cost of introduction. To overcome these problems, we consider a management method that uses a digital watermarking technology, and propose a management model for that method. This paper also introduces comparisons with the existing methods and their characteristics.