Summary This paper proposes hash chain algorithm that generates more secure key than conventional method and secure encryption method that each key generated by hash chain algorithm is respectively applied to block. Also, we encrypt separate key using key separate method after authenticating user by user authentication method via on/off line, and attacker cannot get complete key although the key is disclosed by sending the key to client one by one. After we design and implement proposed system, we take experiment for a performance analysis using various size of digital content files. As a result, proposed system can securely transmit a key, and the key is encrypted not to decrypt whole data against key disclosure. Finally, the time for an encryption and decryption is analogous to conventional method when client system replays video file.
['Kun-Won Jang', 'Chan-Kil Park', 'Jung-Jae Kim', 'Moon-Seog Jun']
A Study on DRM System for On/Off Line Key Authentication