Motion trajectory based video authentication
With the relentless digitization of commercial media, it is increasingly susceptible to the violation of its intellectual property rights. We address the issue of authenticating digital video in this paper by presenting a novel technique based on motion trajectory and cryptographic secret sharing. Given a video, we segment it into shots and select the key frames in a shot based on the motion trajectory. We then consider these key frames as shares of a secret-sharing scheme for color images. We then reconstruct the secret corresponding to these shares. This secret frame is deemed as the secret key of this shot. Utilizing the secret keys of all the shots, we hierarchically construct the master key for the entire video by recursively employing the same method of color image sharing. Any modifications in a shot or in the important content of a shot will be reflected as changes in the computed master key. Thus, any video can be authenticated by comparing its computed master key with the original master key. The advantages of the proposed technique are that we take the correlation among the video frames into account, all authentication data is encapsulated within the master key, and this master key authentication information need not be embedded into the video. Thus the video quality is not affected by the auxiliary authentication information.