Spread-Spectrum Watermarking Security

2013

Information Hiding

Abstract. Whereas the embedding distortion, the payload and the robustness of digital watermarking schemes are well understood, the notion of security is still not completely well defined. The approach proposed in the last five years is too theoretical and solely considers the embedding process, which is half of the watermarking scheme. This paper proposes a new measurement of watermarking security, called the effective key length, which captures the difficulty for the adversary to get access to the watermarking channel. This new methodology is applied to the Distortion Compensated Dither Modulation Quantized Index Modulation (DC-DM QIM) watermarking scheme where the dither vector plays the role of the secret key. This paper presents theoretical and practical computations of the effective key length. It shows that this scheme is not secure as soon as the adversary gets observations in the Known Message Attack context.

Section: The Problem With Previous Security Measuresmentioning

confidence: 99%

“…The problem is that the previous methodology on this topic [1], although applied on Spread Spectrum [2] and Dither Modulated Distortion Compensated Quantized Index Modulation (DM-DC QIM) [3] watermarking schemes, is not so successful. As detailed in Sect.…”

Section: Introductionmentioning

confidence: 99%

A New Measure of Watermarking Security Applied on QIM

Furon

2013

Information Hiding

“…The use of chordal distance for watermarking security analysis was first proposed by Pérez-Freire et al [14] and is convenient because the SCD = 0 if the estimated subspaces are equal and SCD = Np if they are orthogonal.…”

Section: Estimation Assessmentmentioning

confidence: 99%

Two key estimation techniques for the broken arrows watermarking scheme

Proceedings of the 11th ACM Workshop on Multimedia and Security

Westfeld

2009

This paper presents two different key estimation attacks targeted for the image watermarking system proposed for the BOWS-2 contest. Ten thousands images are used in order to estimate the secret key and remove the watermark while minimizing the distortion. Two different techniques are proposed. The first one combines a regression-based denoising process to filter out the component of the original images and a clustering algorithm to compute the different components of the key. The second attack is based on an inline subspace estimation algorithm, which estimates the subspace associated with the secret key without computing eigen decomposition. The key components are then estimated using Independent Component Analysis and a strategy designed to leave efficiently the detection region is presented. On six test images, the two attacks are able to remove the mark with very small distortions (between 41.8 dB and 49 dB). Categories and Subject Descriptors General TermsSecurity, Algorithms Keywords Zero-bit watermarking algorithm , Security, Attack, Subspace Estimation INTRODUCTIONIf watermarking robustness deals with the performance of a watermarking scheme against common processing operations (re-compression, transcoding, editing operations), the Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. security of a watermarking scheme is addressed whenever an adversary is part of the game and tries to remove the watermark. There are two important families of security attacks:• Sensitivity attacks [1] aim at removing the watermark by using the watermark detector as an oracle,

“…The problem addressed in this paper is the following: the methodology to assess the security levels of watermarking schemes, proposed in [2], [3], [4], [5], [6], doesn't completely capture T. Kalker's definition. These papers are based on the translation of C. E. Shannon's definition of security for symmetric crypto-systems [7] into watermarking terms.…”

Section: Introductionmentioning

confidence: 99%

A New Measure of Watermarking Security: The Effective Key Length

IEEE Trans.Inform.Forensic Secur.

Furon

2013

Whereas the embedding distortion, the payload and the robustness of digital watermarking schemes are well understood, the notion of security is still not completely well defined. The approach proposed in the last five years is too theoretical and solely considers the embedding process, which is half of the watermarking scheme. This paper proposes a new measure of watermarking security, called the effective key length, which captures the difficulty for the adversary to get access to the watermarking channel. This new methodology is applied here to additive spread spectrum schemes where theoretical and practical computations of the effective key length are proposed. Experimental protocols using either Monte-Carlo simulations, region approximation or rare event probability estimator allow good evaluation of this quantity. For Improved Spread Spectrum (ISS), our analysis exhibits setups where i) the robustness and the security of the scheme are superior to Spread Spectrum and ii) estimating the secret keys from the observations only is not the best way to break the scheme. Moreover a comparison with Correlation Aware Spread Spectrum (CASS) shows that ISS offers a better security than CASS for a given robustness.