Data administration method which prevents the infringement of a copyright by encrypting and distributing digital content, and readily grasps which contents are contained in the digital content included in the data. Preparing symbol information symbolized so as to visually and auditorily recognize the contents of the digital content that conduct distribution (Step S12), embedding the symbol information in a header data section (Step S13), encrypting the digital content (Step S15), embedding consent information including the information on the contents key in the header data section as an electronic watermark (Step S16), and compositing the real data section and the consent-information-added header data section and distributing the composite data (Step S17).