An efficient dispute resolving method for digital images

Resolving rightful ownerships of digital images is an active research area of watermarking. Though a watermark is used to prove the owner's ownership, an attacker can invalidate it by creating his fake original image and its corresponding watermark. This kind of attack is called ambiguity attack and can be tackled either by use of non-invertible water-marking schemes or by use of zero-knowledge watermark detections. If a non-invertible watermarking scheme is used, then the owner should reveal her original image which should be kept secret. And if a zero-knowledge watermark detection is used, then no one can verify the claimed ownership unless the owner is involved. Moreover, in case of zero-knowledge watermark detection, the protocol is relatively complicated and needs more computations. In this paper, using the MSBs string of the original image other than the original image itself, we propose an efficient dispute resolving method while preserving secrecy of the original image.