A time-stamping protocol for digital watermarking

Digital watermarking techniques have recently been proposed for the copyright protection of digital media. Time-stamping is one technique used to ascertain at what time a certain digital medium was created or signed. In this paper, a new time-stamping protocol for digital watermarking is proposed that adds a time-stamp to digital watermarking algorithms through a trusted third party. The goals of the proposed protocol are (1) the trusted third party is not required to store any messages relating to the signed time-stamp, (2) it is suitable for all digital watermarking algorithms, and (3) it contains a time stamp that is impervious to forgery.