The Research Of Copyright Protection Protocol Based On Digital Watermarking

With the development of the computer and network technology, digital works (image, text, audio, video, and so on) are getting very easy to store, duplicate and transmit. We can get digital copies the same as the original one easily. But the copyright problem caused from this has already become the serious social concern day by day. Such digital works as digital image need a kind of effective copyright protection method.Digital watermarking has offered an effective method for solving these problems. The copyright holder can embed the watermark in the digital works created by him. When the copyright dispute or the situation of the pirate appears, the copyright holder can draw out the watermark from the digital works, regard as evidence. Thus the copyright of the digital works can be well protected. In the trading process, the copyright holder can embed a unique watermark, in each copy of the data that is distributed. It at a later point in time, unauthorized copies of the data are found, and then the origin of the copy can be determined by retrieving the unique watermark corresponding to each buyer.But relying on digital watermarking solely is not enough, it can't totally solve all problems in copyright protection; it is easy to be attacked by the protocol attack. The attacker can embed his watermark in the works; we can't solve the copyright ownership problem of the works, because we unable to judge the priority of the embedded watermark. In the trading process, the copyright holder can duplicate and sell illegally the works which contain buyer's watermark, so the buyer's legitimate rights have been infringed.Based on the expatiation and compare of recent watermarking algorithms, with discussion of the attack on watermarking, this paper summarizes the characteristic of watermarking technology for copyright protection.With the analysis of present copyright protection scheme, contra pose the discoverable weakness and deficiency, this paper propose a secure and fair digital copyright protection protocol based on digital watermarking and digital signature.In this scheme, we embed watermarks of buyer and copyright holder into the image both, and insert a digest information of origin image into the buyer's watermark to prevent the copyright holder who embeds watermark into image concretely to embezzle the buyer's watermark, the attacker can't capture or tamper the watermarked image too, so we can protect the copyright of copyright holder. And we use the permute function and digital signature to restrict the copyright holder's behavior, protect the rights of rightful buyer, implement the justice.The upper security of our protocol is based on cryptography technology. The use of Hash function prevents the fake-watermark attack, and the digital signature and watermarking certificate authority technology avoids the man-in-the-middle attack.