Patent ID: 7685071

Claim:
A mobile communication terminal comprising: a first interface programmed to communicate with a content server; a second interface programmed to communicate with an external device; and a control unit programmed to: download, via the first interface, a content from the content server; assign a download time to the content when the content is downloaded, wherein the download time is one of: (i) generated by a clock unit provided in the mobile communication terminal , and (ii) generated based on a time obtained from a base station; generate a first encryption key based on at least the download time and information inherent to the mobile communication terminal; obtain an encrypted content by encrypting the content with the generated first encryption key; move, via the second interface, the encrypted content and the download time to the external device; receive, via the second interface, a key generation request including the download time from the external device; generate a second encryption key based on the download time extracted from the key generation request and the information inherent to the mobile communication terminal; and transmit the second encryption key to the external device; whereby the content becomes playable at the external device when the second encryption key coincides with the first encryption key, and wherein the mobile communication terminal is programmed to receive the key generation request from the external device when an input is made on the external device instructing the encrypted content to be played on the external device.