JPEG forensics scheme for signature embedding and packet-level detection

As the volume of multimedia digital information transmitted over the Internet continues to rise, the problem of preventing the unauthorized tampering and dissemination of digital content has emerged as a major concern. Thus, the present study proposes a forensic scheme for tracking the dissemination of copyright-protected JPEG images over the Internet. The proposed scheme incorporates two basic mechanisms, namely signature embedding and signature detecting. To preserve the quality of the protected JPEG images, the signature is embedded at the application layer. By contrast, the signature detection process is performed at the packet level in order to improve the scalability of the proposed mechanism. For any flows regarded as suspicious, the signatures embedded in the JPEG packet trains are compared with the known digital signatures for forensic purposes. The experimental results show that the embedded signature has no effect on the visual quality of the JPEG image. Moreover, it is shown that the computational complexity of the proposed detection scheme is significantly lower than that of existing application-level schemes. Thus, the scheme provides an ideal solution for the forensic analysis of JPEG streams over large-scale network environments such as the Internet.