A Secure Watermarking Protocol Designed for Online System

One of most desired goal of digital watermark is to protect copyright, which is hard to realize without accompanying a well designed protocol according to different applications. Online system, such as digital museum, is an advanced platform to show digital works while valued data are prone to be pirated. A secure watermarking protocol is designed to protect copyright of online system in this paper. Through embedding two watermarks separately by two independent parties in a secure way, the innocent can not be framed and the culpable not be denied. This paper not focus on watermark algorithm itself but on establishing a protocol to using watermark algorithm in online system to trace pirate.