In the past more than one decade, hundreds of reversible data hiding (RDH) algorithms have been reported. Via exploring the correlation between the neighboring pixels (or coefficients), extra information can be embedded into the host image reversibly. However, these RDH algorithms cannot be accomplished in encrypted domain directly, since the correlation between the neighboring pixels will disappear after encryption. In order to accomplish RDH in encrypted domain, specific RDH schemes have been designed according to the encryption algorithm utilized. In this paper, we propose a new simple yet effective framework for RDH in encrypted domain. In the proposed framework, the pixels in a plain image are first divided into sub-blocks with the size of $m\times n$ . Then, with an encryption key, a key stream (a stream of random or pseudorandom bits/bytes that are combined with a plaintext message to produce the encrypted message) is generated, and the pixels in the same sub-block are encrypted with the same key stream byte. After the stream encryption, the encrypted $m\times n$ sub-blocks are randomly permutated with a permutation key. Since the correlation between the neighboring pixels in each sub-block can be well preserved in the encrypted domain, most of those previously proposed RDH schemes can be applied to the encrypted image directly. One of the main merits of the proposed framework is that the RDH scheme is independent of the image encryption algorithm. That is, the server manager (or channel administrator) does not need to design a new RDH scheme according to the encryption algorithm that has been conducted by the content owner; instead, he/she can accomplish the data hiding by applying the numerous RDH algorithms previously proposed to the encrypted domain directly.

New Framework for Reversible Data Hiding in Encrypted Domain

This paper proposes an adaptive watermarking scheme for e-government document images. The adaptive scheme combines the discrete cosine transform (DCT) and the singular value decomposition (SVD) using luminance masking. As a core of masking model in the human visual system (HVS), luminance masking is implemented to improve noise sensitivity. Genetic algorithm (GA), subsequently, is employed for the optimization of the scaling factor of the masking. Involving a number of steps, the scheme proposed through this study begins by calculating the mask of the host image using luminance masking. It is then continued by transforming the mask on each area into all frequencies domain. The watermark image, following this, is embedded by modifying the singular values of DCT-transformed host image with singular values of mask coefficient of host image and the control parameter of DCT-transformed watermark image using Genetic Algorithm (GA). The use of both the singular values and the control parameter respectively, in this case, is not only to improve the sensitivity of the watermark performance but also to avoid the false positive problem. The watermark image, afterwards, is extracted from the distorted images. The experiment results show the improved adaptive performance of the proposed scheme is in resistant to several types of attacks in comparison with the previous schemes; the adaptive performance refers to the adaptive parameter of the luminance masking functioned to improve the performance or robustness of an image from any attacks.

An adaptive watermarking scheme for e-government document images

In image watermarking, information is embedded into cover media to prove ownership. Various watermarking techniques have been proposed by many authors in the last several years which include spatial domain and transform domain watermarking. Wavelet based image watermarking is gaining more popularity because of its resemblance with the human visual system. This paper elaborates suitability of wavelet transform for image watermarking, wavelet transform based image watermarking process, classification and analysis of wavelet based watermarking techniques. The purpose of this paper is to provide a comprehensive review of the existing literature available on wavelet based image watermarking methods. It will be useful for researchers to implement effective image watermarking method.

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Literature Review of Wavelet based Digital Image Watermarking Techniques

Data hiding technology plays an important role in many areas related to people’s life, such as military and medical images. However, it is difficult to obtain high embedding capacity in compressed images, and it may cause obvious image distortion. Also, the target image’s file size should be controlled, as a significant increase in file size may cause the interceptor’s attention. In the field of data hiding, many people have proposed feasible solutions. However, considering the visual quality and embedding rate of images, more improvements are needed. In this paper, the histogram shift is used to realize data hiding of JPEG images. The secret message bits are embedded in the high-frequency coefficients to ensure a higher embedding rate, and the high-frequency coefficients are obtained by histogram distribution. The optimal threshold is used to select a discrete cosine transform (DCT) coefficient sub-block that is suitable to embed the secret message and further improve the visual quality of the target image. The experiments show that our solution is significantly better than the most advanced technology in terms of embedding rate and visual quality.

A High-Imperceptibility and Histogram-Shifting Data Hiding Scheme for JPEG Images

A blind watermarking technique based on QR decomposition is proposed on still images. The method is presented in spatial as well as transform domains and its robustness against some well-known image processing attacks is evaluated. It is shown that the QR decomposition offers capacity and robustness comparable to or better than similar watermarking based on the DCT and SVD transformations. Also, an interesting property of QR decomposition, which for the first time has been introduced by our previous paper, is proved and put in practice in more details.

Fast and robust watermarking in still images based on QR decomposition

Digital watermarking has been proposed as a solution to the problem of copyright protection of multimedia files in networked environments. In this paper, a block-based adaptive image watermarking scheme using Just Noticeable Difference (JND) is proposed. The proposed scheme is performed in both pixel domain and Discrete Cosine Transform (DCT) domain. It first divides host image into 8×8 blocks. After that, it calculates the capacity of each block to embed information without being perceptible. This capacity can be determined by JND threshold, which is one feature of Human Visual System (HVS) model and it measures the smallest difference between watermarked and host image that is just detectable for human vision. The DCT coefficients of each block are adaptively modified according to the JND threshold values. Watermarks will be embedded in the modified DCT coefficients. Performance and experimental results of proposed scheme are presented. As expected, high robustness of watermarked images without image quality distortion can be achieved.

Block-based adaptive image watermarking scheme using Just Noticeable Difference

In this paper, we present a novel high capacity reversible image authentication scheme based on digital watermarking. The proposed technique slightly shifts the histogram of the difference image generated from the original cover image, thus modifies pixel values tenderly while obtaining a high embedding capacity. The distortion caused by embedding can be completely removed after the hidden data has been extracted if the watermarked image is authentic. The watermark data is blockwisely embedded so the tampered positions in a forgery image can be blockwisely detected wherever any disturbance is imposed. Experimental results demonstrate that the capacity of the proposed watermarking scheme is much higher than some state-of-art schemes with comparable PSNR values, while the computation complexity is kept low.

High capacity reversible image authentication based on difference image watermarking

Unsupervised Color-Texture Image Segmentation Based on A New Clustering Method

This paper introduces a novel approach of watermarking for copyright protection applications using the singular value decomposition (SVD) in the Dual Tree Complex Wavelet Transform (DT-CWT) domain. After applying the 2-level DT-CWT to the cover grayscale image, we apply the SVD to each high-pass subband obtained. The singular values in each subband are then modified by the singular values of the DT-CWT-transformed visual watermark. Modification in all subbands allows the development of a watermarking scheme that is robust to a wide range of attacks. Experimental results demonstrate that the proposed watermarking scheme is highly robust to various attacks.

Robust Image Watermarking Based on singular value decomposition in DT-CWT domain

In this paper, a blind audio watermarking scheme using stereo signals is proposed. In the proposed scheme, each bit of watermark bit stream is embedded into “non–silent” samples of stereo audio signals. The watermark bits can be embedded by replacing least significant bit or bits in higher bit layers of original signal samples. Robustness and performance of this audio watermarking scheme under different types of attacks,such as addition of noise, MP3 compression and re-sampling are investigated. Watermark extraction rates are calculated.Different audio signals including music, speech are used for the experiments. It is found that the proposed audio watermarking scheme, compared with the use of single channel signals, is much more robust against addition of white noise.

Shengming Li

Papers

Block-based adaptive image watermarking scheme using Just Noticeable Difference

High capacity reversible image authentication based on difference image watermarking

Unsupervised Color-Texture Image Segmentation Based on A New Clustering Method

Robust Image Watermarking Based on singular value decomposition in DT-CWT domain

Bit Replacement Audio Watermarking Using Stereo Signals