Digital watermarking is a key ingredient to copyright protection. It provides a solution to illegal copying of digital material and has many other useful applications such as broadcast monitoring and the recording of electronic transactions. Now, for the first time, there is a book that focuses exclusively on this exciting technology. Digital Watermarking covers the crucial research findings in the field: it explains the principles underlying digital watermarking technologies, describes the requirements that have given rise to them, and discusses the diverse ends to which these technologies are being applied. As a result, additional groundwork is laid for future developments in this field, helping the reader understand and anticipate new approaches and applications.

Digital Watermarking

A novel method of steganographic embedding in digital images is described, in which each secret digit in a (2n+1)-ary notational system is carried by n cover pixels and, at most, only one pixel is increased or decreased by 1. In other words, the (2n+1) different ways of modification to the cover pixels correspond to (2n+1) possible values of a secret digit. Because the directions of' modification are fully exploited, the proposed method provides high embedding efficiency that is better than previous techniques

Efficient Steganographic Embedding by Exploiting Modification Direction

In order to improve the capacity of the hidden secret data and to provide an imperceptible stego-image quality, a novel steganographic method based on least-significant-bit (LSB) replacement and pixel-value differencing (PVD) method is presented. First, a different value from two consecutive pixels by utilising the PVD method is obtained. A small difference value can be located on a smooth area and the large one is located on an edged area. In the smooth areas, the secret data is hidden into the cover image by LSB method while using the PVD method in the edged areas. Because the range width is variable, and the area in which the secret data is concealed by LSB or PVD method are hard to guess, the security level is the same as that of a single using the PVD method of the proposed method. From the experimental results, compared with the PVD method being used alone, the proposed method can hide a much larger information and maintains a good visual quality of stego-image.

http://isrc.ccs.asia.edu.tw/www/myjournal/P211.pdf

Image steganographic scheme based on pixel-value differencing and LSB replacement methods

Digital steganography is the art of inconspicuously hiding data within data. Steganography's goal in general is to hide data well enough that unintended recipients do not suspect the steganographic medium of containing hidden data. The software and links mentioned in this article are just a sample of the steganography tools currently available. As privacy concerns continue to develop along with the digital communication domain, steganography will undoubtedly play a growing role in society. For this reason, it is important that we are aware of digital steganography technology and its implications. Equally important are the ethical concerns of using steganography and steganalysis. Steganography enhances rather than replaces encryption. Messages are not secure simply by virtue of being hidden. Likewise, steganography is not about keeping your message from being known - it's about keeping its existence from being known.

Digital steganography: hiding data within data

In this paper, we shall propose a new image steganographic technique capable of producing a secret-embedded image that is totally indistinguishable from the original image by the human eye. In addition, our new method avoids the falling-off-boundary problem by using pixel-value differencing and the modulus function. First, we derive a difference value from two consecutive pixels by utilizing the pixel-value differencing technique (PVD). The hiding capacity of the two consecutive pixels depends on the difference value. In other words, the smoother area is, the less secret data can be hidden; on the contrary, the more edges an area has, the more secret data can be embedded. This way, the stego-image quality degradation is more imperceptible to the human eye. Second, the remainder of the two consecutive pixels can be computed by using the modulus operation, and then secret data can be embedded into the two pixels by modifying their remainder. In our scheme, there is an optimal approach to alter the remainder so as to greatly reduce the image distortion caused by the hiding of the secret data. The values of the two consecutive pixels are scarcely changed after the embedding of the secret message by the proposed optimal alteration algorithm. Experimental results have also demonstrated that the proposed scheme is secure against the RS detection attack.

(Journal of Systems and Software, 81(1):150-158)A high quality steganographic method with pixel-value differencing and modulus function

This letter presents a novel steganography scheme capable of concealing a piece of critical information in a host message which is a binary image (e.g., a facsimile). A binary matrix and a weight matrix are used as secret keys to protect the hidden information. Given a host image of size m/spl times/n, the proposed scheme can conceal as many as /spl lfloor/log/sub 2/ (mn+1)/spl rfloor/ bits of data in the image by changing, at most, two bits in the host image. This scheme can provide a higher security, embed more information, and maintain a higher quality of the host image than available schemes.

https://ir.nctu.edu.tw:443/bitstream/11536/28595/1/000177644800006.pdf

A secure data hiding scheme for binary images

In this paper we propose a new steganography scheme for hiding a piece of critical information in a host binary image (such as facsimiles). A secret key and a weight matrix are used to protect the hidden data. Given an image block of size m/spl times/n, our scheme can hide as many as [log/sub 2/(mn+1)] bits of data in the image by changing at most 2 bits in the image. This scheme, as compared to an existing scheme by M. Y. Wu et al. 1998), can provide higher security, embed more data, and maintain higher quality of the host image.

A secure data hiding scheme for two-color images

In an earlier paper (Chen et al., 2000), we proposed a steganography scheme for hiding a piece of critical information in a host binary image. That scheme ensures that, in each m /spl times/ n image block of the host image, as many as [log/sub 2/ (mn + 1)] bits can be hidden in the block by changing at most 2 bits in the block. We propose a new scheme that improves (Chen et al., 2000) in its capability to maintain higher quality of the host image after data hiding by sacrificing some data hiding space. The new scheme can still offer a good data hiding ratio. It ensures that, for any bit that is modified in the host image, the bit is adjacent to another bit which has a value equal to the former's new value. Thus, the hiding effect is quite invisible.

https://ir.nctu.edu.tw:443/bitstream/11536/28670/1/000176493300013.pdf

Data hiding in 2-color images

In an earlier paper, we propose a steganography scheme for hiding a piece of critical information in a host binary image. That scheme ensures that in each m/spl times/n image block of the host image, as many as [log/sub 2/(mn+1)] bits can be hidden in the block by changing at most 2 bits in the block. As a sequel of that work, in this paper we propose a revised scheme that can maintain higher quality of the host image by sacrificing some data hiding space. The new scheme can still offer a good data hiding ratio. It ensures that for any bit that is modified in the host image, the bit is adjacent to another bit which has a value equal to the former's new value. Thus, the hiding effect is quite invisible.

Hsiang-Kuang Pan

Papers

A secure data hiding scheme for binary images

A secure data hiding scheme for two-color images

Data hiding in 2-color images

Secure and invisible data hiding in 2-color images