A reception apparatus includes a first timer and sends to a distribution apparatus a first date-time clocked by the first timer. The distributing apparatus includes a second timer, and generates expiry information based on a difference obtained by subtracting, from the first date-time, a second date-time that is clocked by the second timer. The expiry information is used to adjust a usage expiry date-time of a content. The reception apparatus judges whether playback of the content is permitted based on the first timer and the expiry information.
With this arrangement, unauthorized use of the content beyond the expiry date-time is prevented.