A variance-based public verifiable copyright protection scheme surviving intentional attacks

Abstract

Digital signature and digital timestamp techniques provide well-defined security mechanisms for copyright protection. However, these techniques are not suitable for directly dealing with digital images. For this reason, digital watermarking has received considerable attention for copyright protection. Unfortunately, there are still some challenges in the proposed watermarking schemes. Here cryptographic tools are introduced into watermarking in such a way that the advantages of both cryptographic tools and digital watermarking are available. Publicly verifiable and distortion tolerance properties are therefore possible. In this paper, a variance-based copyright protection method that does not require the original image for copyright logo extraction is proposed. This new method is both lossless and robust. The present scheme is strong enough to resist malicious manipulations including blurring, JPEG compression, noising, sharpening, scaling, cropping, printing-Xeroxing-scanning and unZign and StirMark attacks, while resisting certain intentional attacks, including counterfeiting, collusion/averaging and copy attacks. A series of experiments is conducted to prove the robustness of this method. It is worthwhile to mention that some of these attacks still challenge many watermarking methods. Based on digital signature and digital timestamping, the ownership of the digital image can be publicly verified.

Keywords:

• digital watermarking
• copyright protection
• discrete wavelet transform
• StirMark
• unZign
• digital signature
• digital timestamp