PCMHoDC A Scheme to Protect Copyright & Modification History of Digital Contents
Heejae Park, Jong Kyoung Kim · Information Security · 2003
Nowadays. protecting digital contents becomes important because it is easy to copy them and hard to distinguish the copy from the original one. As the Internet becomes wider and faster. digital contents are distributed illegally wider and faster than ever. Much research is conducted on preventing illegal distribution and on developing new protection technologies. such as digital watermarking. digital right management. etc. But these technologies are mainly used for commercial and business purposes. Moreover. these technologies are based on the assumption that digital contents will not be modified after being distributed by the contents owner. In this paper. we propose a new scheme to protect against the illegal distribution of modifiable digital contents. The proposed scheme also manages moditication history and the copyright information of modified digital contents. The proposed scheme assumes that the system is composed of server. client. and application that manages modification history. The application exists in the client side and has a secret key. Any legal user receives encrypted digital contents from the server via this application. but cannot place decrypted contents into storage. If a user has distributed his digital contents and his private key to others. our scheme can determine who has distributed them. We compare our scheme with previous technologies such as simple encryption method. digital watermarking. digital right management. and secure tile system. and show that the proposed scheme has better characteristics.