Security analysis of a key based color image watermarking vs. a non-key based technique in telemedicine applications

摘要

Recently, digital watermarking has become an important technique to preserve patients' privacy in telemedicine applications. Since, medical information are highly sensitive, security of watermarked medical images becomes a critical issue in telemedicine applications. In this paper, two targeted attacks have been proposed against a key based color image watermarking scheme and also a non-key based one, in order to evaluate their security in telemedicine applications. The target schemes are SVD-based and QR-based color image watermarking algorithms, which their embedding procedures are quit the same. The proposed attacks exploit the prior knowledge of the watermarking algorithms to make changes in the exact embedding spaces. Thus, these changes would cause disruption in extraction procedure. Our experimental results show that the key based watermarking scheme is more secure than the non-key based one. This is because the proposed targeted attack needs to distort the key based watermarked images more than non-key based ones to remove the embedded watermarks. Our proposed targeted attacks also have more efficient performance in removing watermarks than other general attacks such as JPEG compression, Gaussian noise and etc. Finally, these attacks have been proposed to show the vulnerabilities of watermarking schemes in order to help the designers to implement more secure schemes.