Showing papers on "Digital watermarking published in 2002"

An SVD-based watermarking scheme for protecting rightful ownership

Abstract: Digital watermarking has been proposed as a solution to the problem of copyright protection of multimedia documents in networked environments. There are two important issues that watermarking algorithms need to address. First, watermarking schemes are required to provide trustworthy evidence for protecting rightful ownership. Second, good watermarking schemes should satisfy the requirement of robustness and resist distortions due to common image manipulations (such as filtering, compression, etc.). In this paper, we propose a novel watermarking algorithm based on singular value decomposition (SVD). Analysis and experimental results show that the new watermarking method performs well in both security and robustness.

Lossless data embedding--new paradigm in digital watermarking

Abstract: One common drawback of virtually all current data embedding methods is the fact that the original image is inevitably distorted due to data embedding itself. This distortion typically cannot be removed completely due to quantization, bit-replacement, or truncation at the grayscales 0 and 255. Although the distortion is often quite small and perceptual models are used to minimize its visibility, the distortion may not be acceptable for medical imagery (for legal reasons) or for military images inspected under nonstandard viewing conditions (after enhancement or extreme zoom). In this paper, we introduce a new paradigm for data embedding in images (lossless data embedding) that has the property that the distortion due to embedding can be completely removed from the watermarked image after the embedded data has been extracted. We present lossless embedding methods for the uncompressed formats (BMP, TIFF) and for the JPEG format. We also show how the concept of lossless data embedding can be used as a powerful tool to achieve a variety of nontrivial tasks, including lossless authentication using fragile watermarks, steganalysis of LSB embedding, and distortion-free robust watermarking.

Digital Watermarking

Abstract: Summary form only given. The ability to represent audio and video digitally and its vast popularity poses enormous challenges in protection against unauthorized use, copy and distribution in open, highly uncontrolled Internet environment. Digital watermarking, a technology for insertion of imperceptible information into multimedia content offers a solution for authentication and suitable action thereof. This is a rapidly maturing technology. Initiatives within the industry are ongoing for various forms of multimedia. Technology alone is unlikely to address all the copy protection issues. Business models and legal support also play an important role in tackling them.

Geometrically invariant watermarking using feature points

Abstract: This paper presents a new approach for watermarking of digital images providing robustness to geometrical distortions. The weaknesses of classical watermarking methods to geometrical distortions are outlined first. Geometrical distortions can be decomposed into two classes: global transformations such as rotations and translations and local transformations such as the StirMark attack. An overview of existing self-synchronizing schemes is then presented. Theses schemes can use periodical properties of the mark, invariant properties of transforms, template insertion, or information provided by the original image to counter geometrical distortions. Thereafter, a new class of watermarking schemes using the image content is presented. We propose an embedding and detection scheme where the mark is bound with a content descriptor defined by salient points. Three different types of feature points are studied and their robustness to geometrical transformations is evaluated to develop an enhanced detector. The embedding of the signature is done by extracting feature points of the image and performing a Delaunay tessellation on the set of points. The mark is embedded using a classical additive scheme inside each triangle of the tessellation. The detection is done using correlation properties on the different triangles. The performance of the presented scheme is evaluated after JPEG compression, geometrical attack and transformations. Results show that the fact that the scheme is robust to these different manipulations. Finally, in our concluding remarks, we analyze the different perspectives of such content-based watermarking scheme.

Hierarchical watermarking for secure image authentication with localization

Abstract: Several fragile watermarking schemes presented in the literature are either vulnerable to vector quantization (VQ) counterfeiting attacks or sacrifice localization accuracy to improve security. Using a hierarchical structure, we propose a method that thwarts the VQ attack while sustaining the superior localization properties of blockwise independent watermarking methods. In particular, we propose dividing the image into blocks in a multilevel hierarchy and calculating block signatures in this hierarchy. While signatures of small blocks on the lowest level of the hierarchy ensure superior accuracy of tamper localization, higher level block signatures provide increasing resistance to VQ attacks. At the top level, a signature calculated using the whole image completely thwarts the counterfeiting attack. Moreover, "sliding window" searches through the hierarchy enable the verification of untampered regions after an image has been cropped. We provide experimental results to demonstrate the effectiveness of our method.

Watermarking relational databases

Abstract: We enunciate the need for watermarking database relations to deter their piracy, identify the unique characteristics of relational data which pose new challenges for watermarking, and provide desirable properties of a watermarking system for relational data. A watermark can be applied to any database relation having attributes which are such that changes in a few of their values do not affect the applications. We then present an effective watermarking technique geared for relational data. This technique ensures that some bit positions of some of the attributes of some of the tuples contain specific values. The tuples, attributes within a tuple, bit positions in an attribute, and specific bit values are all algorithmically determined under the control of a private key known only to the owner of the data. This bit pattern constitutes the watermark. Only if one has access to the private key can the watermark be detected with high probability. Detecting the watermark neither requires access to the original data nor the watermark. The watermark can be detected even in a small subset of a watermarked relation as long as the sample contains some of the marks. Our extensive analysis shows that the proposed technique is robust against various forms of malicious attacks and updates to the data. Using an implementation running on DB2, we also show that the performance of the algorithms allows for their use in real world applications.

A wavelet-based watermarking algorithm for ownership verification of digital images

Abstract: Access to multimedia data has become much easier due to the rapid growth of the Internet. While this is usually considered an improvement of everyday life, it also makes unauthorized copying and distributing of multimedia data much easier, therefore presenting a challenge in the field of copyright protection. Digital watermarking, which is inserting copyright information into the data, has been proposed to solve the problem. In this paper, we first discuss the features that a practical digital watermarking system for ownership verification requires. Besides perceptual invisibility and robustness, we claim that the private control of the watermark is also very important. Second, we present a novel wavelet-based watermarking algorithm. Experimental results and analysis are then given to demonstrate that the proposed algorithm is effective and can be used in a practical system.

Lossless data embedding for all image formats

Abstract: Lossless data embedding has the property that the distortion due to embedding can be completely removed from the watermarked image without accessing any side channel. This can be a very important property whenever serious concerns over the image quality and artifacts visibility arise, such as for medical images, due to legal reasons, for military images or images used as evidence in court that may be viewed after enhancement and zooming. We formulate two general methodologies for lossless embedding that can be applied to images as well as any other digital objects, including video, audio, and other structures with redundancy. We use the general principles as guidelines for designing efficient, simple, and high-capacity lossless embedding methods for three most common image format paradigms - raw, uncompressed formats (BMP), lossy or transform formats (JPEG), and palette formats (GIF, PNG). We close the paper with examples of how the concept of lossless data embedding can be used as a powerful tool to achieve a variety of non-trivial tasks, including elegant lossless authentication using fragile watermarks. Note on terminology: some authors coined the terms erasable, removable, reversible, invertible, and distortion-free for the same concept.

Digital watermarking methods and related toy and game applications

Abstract: The present invention relates to toys and game applications that are enhanced with digital watermarks. In one embodiment, a character card includes a unique identifier in the form of a digital watermark. The identifier is used to link to a database record, which can be updated to reflect changes in game attributes. Some such game attributes include life, character type and name, health, strength, and power levels. The data record can be updated or modified to reflect changes in attributes due to activity or events during a computer software game. The database record can be used by the computer software game to alter or enhance the game. In another embodiment, a toy interacts with toy components or cards via digital watermarks. Digital watermarks enhance games, toys and books in still other embodiments.

A survey of watermarking algorithms for image authentication

Abstract: Digital image manipulation software is now readily available on personal computers. It is therefore very simple to tamper with any image and make it available to others. Insuring digital image integrity has therefore become a major issue. Watermarking has become a popular technique for copyright enforcement and image authentication. The aim of this paper is to present an overview of emerging techniques for detecting whether image tampering has taken place. Compared to the techniques and protocols for security usually employed to perform this task, the majority of the proposed methods based on watermarking, place a particular emphasis on the notion of content authentication rather than strict integrity. In this paper, we introduce the notion of image content authentication and the features required to design an effective authentication scheme. We present some algorithms, and introduce frequently used key techniques.

A Frequency‐Domain Approach to Watermarking 3D Shapes

Abstract: This paper presents a robust watermarking algorithm with informed detection for 3D polygonal meshes. The algorithm is based on our previous algorithm [22] that employs mesh-spectral analysis to modify mesh shapes in their transformed domain. This paper presents extensions to our previous algorithm so that (1) much larger meshes can be watermarked within a reasonable time, and that (2) the watermark is robust against connectivity alteration (e.g., mesh simplification), and that (3) the watermark is robust against attacks that combine similarity transformation with such other attacks as cropping, mesh simplification, and smoothing. Experiment showed that our new watermarks are resistant against mesh simplification and remeshing combined with resection, similarity transformation, and other operations..

Data hiding watermarking for halftone images

Abstract: In many printer and publishing applications, it is desirable to embed data in halftone images. We proposed some novel data hiding methods for halftone images. For the situation in which only the halftone image is available, we propose data hiding smart pair toggling (DHSPT) to hide data by forced complementary toggling at pseudo-random locations within a halftone image. The complementary pixels are chosen to minimize the chance of forming visually undesirable clusters. Our experimental results suggest that DHSPT can hide a large amount of hidden data while maintaining good visual quality. For the situation in which the original multitone image is available and the halftoning method is error diffusion, we propose the modified data hiding error diffusion (MDHED) that integrates the data hiding operation into the error diffusion process. In MDHED, the error due to the data hiding is diffused effectively to both past and future pixels. Our experimental results suggest that MDHED can give better visual quality than DHSPT. Both DHSPT and MDHED are computationally inexpensive.

Security of fragile authentication watermarks with localization

Abstract: In this paper, we study the security of fragile image authentication watermarks that can localize tampered areas. We start by comparing the goals, capabilities, and advantages of image authentication based on watermarking and cryptography. Then we point out some common security problems of current fragile authentication watermarks with localization and classify attacks on authentication watermarks into five categories. By investigating the attacks and vulnerabilities of current schemes, we propose a variation of the Wong scheme18 that is fast, simple, cryptographically secure, and resistant to all known attacks, including the Holliman-Memon attack9. In the new scheme, a special symmetry structure in the logo is used to authenticate the block content, while the logo itself carries information about the block origin (block index, the image index or time stamp, author ID, etc.). Because the authentication of the content and its origin are separated, it is possible to easily identify swapped blocks between images and accurately detect cropped areas, while being able to accurately localize tampered pixels.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A framework for evaluating the data-hiding capacity of image sources

Abstract: An information-theoretic model for image watermarking and data hiding is presented in this paper. Previous theoretical results are used to characterize the fundamental capacity limits of image watermarking and data-hiding systems. Capacity is determined by the statistical model used for the host image, by the distortion constraints on the data hider and the attacker, and by the information available to the data hider, to the attacker, and to the decoder. We consider autoregressive, block-DCT, and wavelet statistical models for images and compute data-hiding capacity for compressed and uncompressed host-image sources. Closed-form expressions are obtained under sparse-model approximations. Models for geometric attacks and distortion measures that are invariant to such attacks are considered.

Embedding auxiliary signals with multiple components into media signals

Abstract: A digital watermark system embeds auxiliary signals in multimedia types, including audio, still and moving images, and physical objects. These auxiliary signals, referred to as digital watermarks, include multiple components that can perform differing functions and that are embedded with different levels of redundancy, potentially within different transform domains of the host signal.

Authentication using a digital watermark

Abstract: A method and apparatus for identifying an object include encoding physical attributes of an object where the encoded information is utilized as at least one element for composing a digital watermark for the object. In another embodiment the physical attributes of the object are utilized as a key for accessing information included in a digital watermark for the object.

A vision-based masking model for spread-spectrum image watermarking

Abstract: We present a perceptual model for hiding a spread-spectrum watermark of variable amplitude and density in an image. The model takes into account the sensitivity and masking behavior of the human visual system by means of a local isotropic contrast measure and a masking model. We compare the insertion of this watermark in luminance images and in the blue channel of color images. We also evaluate the robustness of such a watermark with respect to its embedding density. Our results show that this approach facilitates the insertion of a more robust watermark while preserving the visual quality of the original. Furthermore, we demonstrate that the maximum watermark density generally does not provide the best detection performance.

Invisibility and application functionalities in perceptual watermarking an overview

Abstract: Digital watermarking consists of hiding subliminal information into digital media content, also called host data. It can be the basis of many applications, including security and media asset management. In this paper we focus on the imperceptibility requirement for image watermarking. We first provide a functional inventory of image watermarking applications and emphasize the dependency between the application purpose and its need for invisibility. Then, we present a global framework common to most existing watermarking systems. It illustrates the methodology followed to translate human vision research into watermarking technology. It suggests future prospects and highlights the need for dedicated inputs from the human vision community.

Digital image watermarking using singular value decomposition

Abstract: In this paper, we present a technique for watermarking of digital images based on the singular value decomposition. Simulation results are provided which demonstrate the robustness of the proposed technique to a variety of common image degradations. The results of our approach are also compared to other transform domain watermarking methods.

Capacity bounds and constructions for reversible data-hiding

Abstract: An undesirable side effect of many watermarking and data-hiding schemes is that the host signal into which auxiliary data is embedded is distorted. Finding an optimal balance between the amount of information embedded and the induced distortion is therefore an active field of research. With the rediscovery of Costa's (1983) seminal paper entitled Writing on dirty paper, there has been considerable progress in understanding the fundamental limits of the capacity versus distortion of watermarking and data-hiding schemes. For some applications, however, no distortion resulting from auxiliary data, however small, is allowed. In these cases the use of reversible data-hiding methods provide a way out. A reversible data-hiding scheme is defined as a scheme that allows complete and blind restoration (i.e. without additional signaling) of the original host data. Practical reversible data-hiding schemes have been proposed by Fridrich et al. (2002), but little attention has been paid to the theoretical limits. It is the purpose of this paper to repair this situation and to provide some first results on the limits of reversible data-hiding. Admittedly, the examples provided in this paper are toy examples, but they are indicative of more practical schemes that will be presented in subsequent papers.

Watermark systems and methods

Abstract: Various improvements relating to digital watermarking and related technologies are detailed, including methods that enhance security and functionality, and new articles including watermarked puzzles and marked DNA.

Validating self validating security documents with digital watermarks

Abstract: Security documents which has multiple fields or areas each of which contains information that is perceptible in more than one way: One field can contain a visually perceptible image and a digital watermark that can be detected when the image is scanned and processed, another field can contain machine readable OCR text that can be read by both a human and by a programmed computer, and still another field can contain watermark data which can be correlated to the output of a fingerprint reader or apparatus which scans a user's iris. Documents are produced by begining with a template which defines the placements of elements on the document and the interrelationships between hidden and visual information on the document. The template specifies the placement of elements such as images, photographs, and text and it also specifies the interrelationship between information that is visually perceptible to a user of the document and information that is hidden by means of digital watermarks. Different hidden digital watermark data is included in multiple elements of the document. The watermarks in the different graphic elements of the document are correlated to each other and correlated to the visual material on the document. Thus, the document can not be forged by replacing one element (such as a picture) with a similar element from another document. In order to produce a document defined by a particular template, appropriate pictures, graphics and digital data are extracted from a data bank, and watermark data is embedded in the pictures and graphics as appropriate. The merged digital data is then sent to a printing engine and the final document is produced. An automatic validation system of the present invention reads multiple fields on the document, and it also automatically detects information about the user. The various information is correlated to validate the document.

Printable interfaces and digital linking with embedded codes

Abstract: A physical medium is encoded with machine readable information that provides a human interface to a computer system. The information encoded into the medium indicates a computer implemented process, and is encoded according to a spectral encoding scheme, such as encoding by modifying color values of a graphic or other image printed on the medium. For example, a digital watermark or other steganographic data hidden in the image indicates a web page. In response to the user selecting the encoded information area, the machine readable information is decoded, and used to invoke a computer implemented process.

Toward secure public-key blockwise fragile authentication watermarking

Abstract: The authors describe some weaknesses of public-key blockwise fragile authentication watermarkings and the means to make them secure. Wong's original algorithm as well as a number of its variant techniques are not secure against a mere block cut-and-paste or the well known birthday attack. To make them secure, some schemes have been proposed to make the signature of each block depend on the contents of its neighbouring blocks. The authors attempt to maximise the change localisation resolution using only one dependency per block with a scheme they call hash block chaining version 1 (HBC1). They then show that HBC1, as well as any neighbour content-dependent scheme, are susceptible to another forgery technique that they have named a transplantation attack. They also show a new kind of birthday attack that can be effectively mounted against HBC1. To thwart these attacks, they propose using a nondeterministic digital signature together with a signature-dependent scheme (HBC2). Finally, they discuss the advantages of using discrete logarithm signatures instead of RSA for watermarking.

Reversible Watermarking by Difference Expansion

Abstract: Reversible watermark has drawn lots of interest recently. Different from other types of digital watermarks, a reversible watermark has a special feature that the original digital content can be completely restored. In this paper we describe a high capacity and high quality reversible watermarking method based on difference expansion. A noticeable difference between our method and others is that we do not need to compress original values of the embedding area. We explore the redundancy in the digital content to achieve reversibility.

Digital watermarking for ROI medical images by using compressed signature image

Abstract: In medical images, ROI (Region Of Interest) is an area which contains important information and must be stored without any distortion. We propose a digital watermarking method which avoids the distortion of the image data in ROI by embedding signature information into other area than the ROI. Signature image compressed by a progressive coding algorithm is used as the signature information. The most significant information of the signature information is embedded in the nearest area to the ROI. The proposed method can detect the signature image with moderate quality from a clipped image including the ROI. Furthermore, by dividing the contour of the ROI into several regions and embedding the signature information in the regions respectively, the signature image with moderate quality can be acquired from a clipped image including only part of the ROI.

RASH: RAdon soft hash algorithm

Abstract: In this paper, we present a high compression and collision resistant algorithm for images either suitable to extract an indexing pattern of the image and to detect deformations applied to original image. Some transforms are extracting characteristics invariant against geometrical deformations (rotation and scalling). Among them, the Radon transform, largely used in magnetic resonance imaging, is also robust against image processing basic attacks (like compression, filtering, blurring, etc…) and strong attacks (Stirmark). This transformation allows to caracterize easily features of geometrical transforms. It permits also an easy extraction of an indexing vector of the image.

Wavelet-based reversible watermarking for authentication

Abstract: In the digital information age, digital content (audio, image, and video) can be easily copied, manipulated, and distributed. Copyright protection and content authentication of digital content has become an urgent problem to content owners and distributors. Digital watermarking has provided a valuable solution to this problem. Based on its application scenario, most digital watermarking methods can be divided into two categories: robust watermarking and fragile watermarking. As a special subset of fragile watermark, reversible watermark (which is also called lossless watermark, invertible watermark, erasable watermark) enables the recovery of the original, unwatermarked content after the watermarked content has been detected to be authentic. Such reversibility to get back unwatermarked content is highly desired in sensitive imagery, such as military data and medical data. In this paper we present a reversible watermarking method based on an integer wavelet transform. We look into the binary representation of each wavelet coefficient and embed an extra bit to expandable wavelet coefficient. The location map of all expanded coefficients will be coded by JBIG2 compression and these coefficient values will be losslessly compressed by arithmetic coding. Besides these two compressed bit streams, an SHA-256 hash of the original image will also be embedded for authentication purpose.