A steganalytic algorithm for 3D polygonal meshes

Abstract

We propose a steganalytic algorithm for watermarks embedded by Cho et al.'s mean-based algorithm [1]. The main observation is that while in a clean model the means of Cho et al.'s normalized histogram bins are expected to follow a Gaussian distribution, in a marked model their distribution will be bimodal. The proposed algorithm estimates the number of bins through an exhaustive search and then the presence of a watermark is decided by a tailor made normality test. We also propose a modification of Cho et al.'s algorithm which is more resistant to the steganalytic attack and offers an improved robustness/capacity trade-off.

3D mesh steganalysis using local shape features

“…More recently, Yang et al proposed a steganalytic algorithm in [15], specifically designed for the mean-based watermarking algorithm proposed in [9], which estimates the number of bins through exhaustive search and then detects the presence of the secret message by a tailormade normality test. The steganalysis method proposed in this paper relies on extracting a novel feature set from the 3D mesh of the graphical object.…”

A 3D Steganalytic Algorithm and Steganalysis-Resistant Watermarking

“…• A new 3D watermarking algorithm which is more robust than two state-of-the-art techniques [7], [14] in terms of undetectability against the proposed steganalytic attack, offers a better distortion/capacity trade-off and it is robust against standard watermark removal attacks such as smoothing, noise insertion, subdivision and simplification.…”

“…Farid's method for image steganalysis [29] has been extended in [8] to 3D meshes. In Yang et al [7], a specific 3D steganalysis is proposed based on the observation that the natural statistics of the 3D model are disturbed by Cho et al's mean based embedding. The current paper is an extended version of [7] and includes a new watermarking scheme with smaller distortion compared to [7], [14] and better steganalytic properties that make it practically undetectable by the developed steganalytic attack.…”

“…In Yang et al [7], a specific 3D steganalysis is proposed based on the observation that the natural statistics of the 3D model are disturbed by Cho et al's mean based embedding. The current paper is an extended version of [7] and includes a new watermarking scheme with smaller distortion compared to [7], [14] and better steganalytic properties that make it practically undetectable by the developed steganalytic attack. The embedding algorithm is based on histogram shape modification, similarly to some existing image watermarking algorithms [31], [32].…”

“…These algorithms are primarily concerned with the robustness of the watermark, targeting applications such as proof of ownership and copy control, while the undetectability of the embedded watermark does not seem to be a major concern in their evaluation. That also means that 3D model steganalysis is an underdeveloped area and, to the best of our knowledge, there are only a few works [7], [8] in the literature proposing steganalytic algorithms specifically targeting 3D model watermarking. In contrast, the domain of 2D image watermarking has been greatly influenced over the years by the various proposed steganalytic methods [9], [10], [11], [12], [13].…”