Information hiding techniques have recently become important in a number of application areas. Digital audio, video, and pictures are increasingly furnished with distinguishing but imperceptible marks, which may contain a hidden copyright notice or serial number or even help to prevent unauthorised copying directly. Military communications systems make increasing use of traffic security techniques which, rather than merely concealing the content of a message using encryption, seek to conceal its sender, its receiver or its very existence. Similar techniques are used in some mobile phone systems and schemes proposed for digital elections. Criminals try to use whatever traffic security properties are provided intentionally or otherwise in the available communications systems, and police forces try to restrict their use. However, many of the techniques proposed in this young and rapidly evolving field can trace their history back to antiquity; and many of them are surprisingly easy to circumvent. In this article, we try to give an overview of the field; of what we know, what works, what does not, and what are the interesting topics for research.

The growth of new imaging technologies has created a need for techniques that can be used for copyright protection of digital images. Copyright protection involves the authentication of image content and/or ownership and can be used to identify illegal copies of a (possibly forged) image. One approach for copyright protection is to introduce an invisible signal known as a digital watermark in the image. In this paper, we describe digital image watermarking techniques, known as perceptually based watermarks, that are designed to exploit aspects of the human visual system. In the most general sense, any watermarking technique that attempts to incorporate an invisible mark into an image is perceptually based. However, in order to provide transparency (invisibility of the watermark) and robustness to attack, more sophisticated use of perceptual information in the watermarking process is required. Several techniques have been introduced that incorporate a simple visual model in the marking procedure. Such techniques usually take advantage of frequency selectivity and weighing to provide some perceptual criteria in the watermarking process. Even more elaborate visual models are used to develop schemes that not only take advantage of frequency

In this paper we present a new method of digital steganography, entitled Spread Spectrum Image Steganography (SSIS). Steganography, which means "covered writing" in Greek, is the science of communicating in a hidden manner. Following a discussion of steganographic communication theory and review of existing techniques, the new method, SSIS, is introduced. This system hides and recovers a message of substantial length within digital imagery while maintaining the original image size and dynamic range. The hidden message can be recovered using appropriate keys without any knowledge of the original image. Image restoration, errorcontrol coding, and techniques similar to spread spectrum are described, and the performance of the system is illustrated. A message embedded by this method can be in the form of text, imagery, or any other digital signal. Applications for such a data-hiding scheme include in-band captioning, covert communication, image tamperproofing, authentication, embe...

Abstract not found

Digital watermarking has been recently proposed as the mean for copyright protection of multimedia data. This paper first discusses some scenarios in which many current watermarking schemes fail to resolve the rightful ownership of an image. We then identify the key problems and discuss some crucial requirements for a valid invisible watermark detection. In particular, we argue that, for the particular application of resolving rightful ownership using invisible watermarks, it might be crucial to require that the original image not be directly involved in the watermark detection process. A general framework for validly detecting the invisible watermarks is then proposed. We show the effectiveness of this technique based on some visual, model-based watermarking schemes.

Digital watermarking has been recently proposed as the mean for copyright protection of multimedia data. Many of existing watermarking schemes focused on the robust means to mark an image invisibly without really addressing the ends of these schemes. This paper first discusses some scenarios in which many current watermarking schemes fail to resolve the rightful ownership of an image. The key problems are then identified, and some crucial requirements for a valid invisible watermark detection are discussed. In particular, we show that, for the particular application of resolving rightful ownership using invisible watermarks, it might be crucial to require that the original image not be directly involved in the watermark detection process. A general framework for validly detecting the invisible watermarks is then proposed. Some requirements on the claimed signature/watermarks to be used for detection are discussed to prevent the existence of any counterfeit scheme. The optimal detection strategy within the framework is derived. We show the effectiveness of this technique based on some visual-model-based watermark encoding schemes.

The growth of networked multimedia systems has created a need for the copyright protection of digital images. Copyright protection involves the authentication of image ownership and the identification of illegal copies of a (possibly forged) image. One approach is to mark an image by adding an invisible structure known as a digital watermark. In this paper we further study techniques for marking images introduced in [1]. In particular, we describe how our techniques withstand random errors. We also provide more details relative to our verification procedure. Finally, we discuss the recently proposed IBM attack.

An adaptive watermarking technique is introduced in this work. A regional perceptual classifier is employed to assign a noise sensitivity index to each region. The watermark is inserted in the original image according to this index by using block DCT. The detection of the watermark is designed to achieve a desired false alarm probability.

The growth of networked multimedia systems has created a need for the copyright protection of digital images and video. Copyright protection involves the authentication of image content and/or ownership. This can be used to identify illegal copies of a (possibly forged) image. One approach is to mark an image by adding an invisible structure known as a digital watermark to the image. Techniques of incorporating such a watermark into digital images include spatial-domain techniques, transform-domain algorithms and sub-band filtering approaches.

. In this paper we present a new method for reliable blind image steganography that can hide and recover a message of substantial length within digital imagery while maintaining the original image size and dynamic range. Image processing, error-control coding, and spread spectrum techniques are utilized to conceal hidden data and the performance of the technique is illustrated. The message embedded by this method can be in the form of text, imagery, or any other digital signal. Applications for such a data-hiding scheme include in-band captioning, hidden communication, image tamperproofing, authentication, embedded control, and revision tracking. 1 INTRODUCTION Digital steganography, or information hiding, schemes can be characterized by utilizing the theories of communication [1]. The parameters of information hiding such as the amount of data bits that can be hidden, the perceptibility of the message, and its robustness to removal can be related to the characteristics of communicati...