Channel model for watermarks subject to desynchronization attacks

Robert Baeuml; Joachim J. Eggers; Roman Tzschoppe; Johannes Huber

doi:10.1117/12.465286

29 April 2002 Channel model for watermarks subject to desynchronization attacks

Robert Baeuml, Joachim J. Eggers, Roman Tzschoppe, Johannes Huber

Proceedings Volume 4675, Security and Watermarking of Multimedia Contents IV; (2002) https://doi.org/10.1117/12.465286
Event: Electronic Imaging, 2002, San Jose, California, United States

Abstract

One of the most important practical problems of blind Digital Watermarking is the resistance against desynchronization attacks, one of which is the Stirmark random bending attack in the case of image watermarking. Recently, new blind digital watermarking schemes have been proposed which do not suffer from host-signal interference. One of these quantization based watermarking scheme is the Scalar Costa Scheme (SCS). We present an attack channel for SCS which tries to model typical artefacts of local desynchronization. Within the given channel model, the maximum achievable watermark rate for imperfectly synchronized watermark detection is computed. We show that imperfect synchronization leads to inter-sample-interference by other signal samples, independent from the considered watermark technology. We observe that the characteristics of the host signal play a major role in the performance of imperfectly synchronized watermark detection. Applying these results, we propose a resynchronization method based on a securely embedded pilot signal. The watermark receiver exploits the embedded pilot watermark signal to estimate the transformation of the sampling grid. This estimate is used to invert the desynchronization attack before applying standard SCS watermark detection. Experimental results for the achieved bit error rate of SCS watermark detection confirm the usefulness of the proposed resynchronization algorithm.

Citation Download Citation

Robert Baeuml, Joachim J. Eggers, Roman Tzschoppe, and Johannes Huber "Channel model for watermarks subject to desynchronization attacks", Proc. SPIE 4675, Security and Watermarking of Multimedia Contents IV, (29 April 2002); https://doi.org/10.1117/12.465286

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available