Elsevier

Signal Processing

Volume 93, Issue 9, September 2013, Pages 2529-2538
Signal Processing

Steganalysis of a PVD-based content adaptive image steganography

https://doi.org/10.1016/j.sigpro.2013.03.029Get rights and content

Abstract

Pixel-value-differencing (PVD) is a well-known technique for content adaptive steganography. By this technique, secret data are embedded into the differences of adjacent pixels. Recently, a new PVD-based steganographic method is proposed by Luo et al. Besides realizing adaptive embedding using PVD, the new method also exploits a pairwise modification mechanism to reduce the distortion. In this work, a targeted detector is devised to detect the new PVD-based steganography. We show that although content adaptive approach may enhance the stego-security, Luo et al.'s PVD-based scheme is not a good choice for realizing adaptive embedding since it contains a serious design flaw in data embedding procedure and this flaw can lead to possible attacks. More specifically, by counting the differences of adjacent pixels in both vertical and horizontal directions, a folded difference-histogram is generated and we show that Luo et al.'s PVD-based method may arise significant artifact to this histogram which can be exploited for reliable detection. Experimental results verify that Luo et al.'s PVD-based method can be detected by the proposed detector even at a low embedding rate of 0.05 bits per pixel.

Highlights

  • PVD is a well-known technique for content adaptive steganography.

  • A targeted detector is devised to detect a recently proposed PVD-based method.

  • The PVD-based method can be detected even at a low ER of 0.05 bpp.

  • A theoretical analysis of the proposed method is provided.

Introduction

Steganalysis algorithms can be generally classified into two categories: targeted and universal [1], [2], [3], [4]. Targeted algorithms aim to identify the existence of hidden data embedded by a specific steganographic method, whereas universal algorithms intend to detect a wide range of steganography. We consider digital image as cover data and study the technique of targeted steganalysis in this work.

It is widely accepted that taking the characteristics of natural image into account may enhance stego-security. For example, it is obvious that embedding modifications operated in rough regions of a natural image are less perceptible than that in flat regions. Besides, the slight modifications to rough regions cannot be easily perceived by analyzing usual image statistics since the embedding noise is covered by the inherent noise. Thus the content adaptive approach for steganography has the potential to provide a higher level of security. Based on this consideration, Wu et al. proposed the so-called pixel-value-differencing (PVD) steganography [5], in which the difference value of a pixel pair is considered as a smoothness measurement and more data bits will be embedded into the pair if its difference is relatively large. Thereafter, numerous PVD-based methods are proposed [6], [7], [8], [9] and their security are also discussed [10], [11], [12], [13].

Recently, a new PVD-based method is proposed by Luo et al. [14]. By incorporating PVD with the pairwise embedding algorithm of Mielikainen [15], this method can realize content adaptive embedding and meanwhile provide a better PSNR compared with some previously proposed PVD-based methods. The experimental results reported in [14] show that this method is secure in resisting state-of-the-art steganalyzers.

In this work, we propose a targeted detector to detect Luo et al.'s PVD-based method. We show that although content adaptive embedding is a way to enhance stego-security, Luo et al.'s PVD-based scheme is not a good choice for realizing adaptive embedding since it contains a serious design flaw in data embedding procedure and this flaw can lead to possible attacks. More specifically, by counting the differences of adjacent pixels in both vertical and horizontal directions, a folded difference-histogram is generated and we show that Luo et al.'s PVD-based method may arise significant artifact to this histogram which can be exploited for reliable detection. By our detector, Luo et al.'s PVD-based method can be detected even at a low embedding rate (secret data bits embedded per pixel, ER for short) of 0.05 bits per pixel (bpp).

The rest of this paper is organized as follows. First, the embedding procedure of Luo et al.'s method is described in Section 2. Then, to better present our idea, we consider to detect a simple case of Luo et al.'s method in Section 3.1. A theoretical analysis of our method for this simple case is also provided. Next, the proposed detector for the general case of Luo et al.'s method is introduced in Section 3.2. Finally, experimental results are reported and conclusions are drawn in 4 Experimental results, 5 Conclusion, respectively.

Section snippets

Embedding procedure of Luo et al.'s method

The data embedding procedure of Luo et al.'s method is described step by step as follows. Some remarks are also included in the description.

Step 1 (pixel pair partition): First, for a pre-selected integer Bz{1,4,8,12}, divide the cover image into non-overlapped blocks of Bz×Bz pixels. Then, for each pixel block, rotate it by a pseudo-random degree chosen from {0°,90°,180°,270°}. Next, rearrange the resulting image as a row vector V by raster scanning. Finally, divide V into non-overlapped

A case study with the block size Bz=1

We consider in this subsection a simple case of Luo et al.'s method where the block size Bz is fixed at 1. Such a case equivalently skips the processing before image raster scanning in Step 1 of Section 2.

Define the difference-histogram of cover image ashc(t)=|{(x,y)V:xy=t}||V|where V is the set defined in Step 1 of Section 2. The corresponding difference-histogram of stego image noted as hs can be defined in a similar way. From Table 1, the change of difference-histogram due to data

Experimental results

The experiments are performed on the BOSSBase v1.00 database [19] which contains 10,000 512×512 gray-scale images. The stego images are obtained by Luo et al.'s method with random Bz{1,4,8,12} and different ER. Then the detector D defined in (22) is computed for both cover and stego images.

The proposed detector is evaluated by comparing it with following prior arts: the second order SPAM proposed by Pevny et al. [20], and the recently proposed detector [12] of Tan and Li which is specifically

Conclusion

In this work, we devised a targeted detector for detecting the recently proposed PVD-based embedding method [14]. We have shown that this PVD-based method may arise significant artifact to the difference-histogram, and it can be well detected even for an ER as low as 0.05 bpp. In this light, we conclude that the PVD-based method [14] is not a good choice to realize content adaptive embedding.

Acknowledgments

The authors would like to thank Dr. Shunquan Tan of Shenzhen University, Shenzhen, China, for providing us the source code in [12]. The work of Bin Li was supported by National Natural Science Foundation of China (61103174) and Fundamental Research General Program of Shenzhen City (JCYJ20120613113535357). The work of Xiangyang Luo was supported by Postdoctoral Science Foundation of China (2012T50842).

References (20)

There are more references available in the full text version of this article.

Cited by (18)

  • Robustness enhancement against adversarial steganography via steganalyzer outputs

    2022, Journal of Information Security and Applications
    Citation Excerpt :

    Since syndrome-trellis codes (STCs) [10,11] perform near the maximum theoretical bound at the second task, steganography research mostly focuses on the design of the cost function, such as WOW [12], UNIWARD [13], HILL [14], MiPOD [15], UERD [16] and J-MiPOD [17] etc. With the development of steganography, many steganalysis methods [18–24] have been proposed. Steganalysis is an image binary classification task that aims to classify cover and stego images.

  • Reversal of pixel rotation: A reversible data hiding system towards cybersecurity in encrypted images

    2022, Journal of Visual Communication and Image Representation
    Citation Excerpt :

    The statistical characteristics of them are extremely similar so that the PVD statistical characteristic may be revealed. After embedding, the PVD distribution has a higher consistency which can also resist the PVD steganalysis [44]. Therefore, we can conclude that our proposed schemes have a dependable capability to guarantee security.

  • High-capacity adaptive steganography based on LSB and Hamming code

    2020, Optik
    Citation Excerpt :

    Therefore, Luo et al. [6] pointed out that the statistical characteristics of the edge regions are more complex than the statistical features of the smooth regions and will be better preserved after data hiding. They proposed a new adaptive steganography that received a lot of attention [7,8]. The adaptive steganography technique [6,9,10] first obtains a statistical global feature of the cover image indicating where the change was made before embedding the LSB or DCT coefficients.

  • A novel image steganography technique based on quantum substitution boxes

    2019, Optics and Laser Technology
    Citation Excerpt :

    The key benefit of this technique is obtaining high embedding capacity. However, LSB-based mechanisms suffer from various attacks and steganalysis as shown in [21–28]. To avoid this deficiency, the secret object should be encrypted before embedding it into the cover image.

  • Matrix embedding in finite abelian group

    2015, Signal Processing
    Citation Excerpt :

    Based on this consideration, Wu et al. proposed the so-called pixel-value-differencing (PVD) steganography [24], in which the difference value of a pixel pair is considered as the smoothness measurement and more data bits will be embedded into a pair if its difference is relatively larger. To the best of our knowledge, the PVD-based approach is the first attempt to realize content-adaptive steganography, and it is extensively studied in the literature including both performance enhancement and security discussions [25–32]. Later on, Fridrich et al. proposed the wet paper code (WPC) based steganography [33,34].

View all citing articles on Scopus
View full text