An LA (License Agent) (or a license chip having the same function as the LA) is disposed in a PC (Personal Computer), a content distribution server, and a medium attached to a PD (Private Device or Portable Device) that use a license for electronic data. A content and electronic data are encrypted corresponding to a license. The encrypted content and electronic data are distributed among them. However, the license is distributed between the LAs as safe communication means. Thus, the license can be correctly managed and transferred.