Showing papers on "Digital watermarking published in 2000"

Quantization index modulation: a class of provably good methods for digital watermarking and information embedding

Abstract: We consider the problem of embedding one signal (e.g., a digital watermark), within another "host" signal to form a third, "composite" signal. The embedding is designed to achieve efficient tradeoffs among the three conflicting goals of maximizing the information-embedding rate, minimizing the distortion between the host signal and composite signal, and maximizing the robustness of the embedding. We introduce new classes of embedding methods, termed quantization index modulation (QIM) and distortion-compensated QIM (DC-QIM), and develop convenient realizations in the form of what we refer to as dither modulation. Using deterministic models to evaluate digital watermarking methods, we show that QIM is "provably good" against arbitrary bounded and fully informed attacks, which arise in several copyright applications, and in particular it achieves provably better rate distortion-robustness tradeoffs than currently popular spread-spectrum and low-bit(s) modulation methods. Furthermore, we show that for some important classes of probabilistic models, DC-QIM is optimal (capacity-achieving) and regular QIM is near-optimal. These include both additive white Gaussian noise (AWGN) channels, which may be good models for hybrid transmission applications such as digital audio broadcasting, and mean-square-error-constrained attack channels that model private-key watermarking applications.

Watermarking digital image and video data. A state-of-the-art overview

Abstract: The authors begin by discussing the need for watermarking and the requirements. They go on to discuss digital watermarking techniques based on correlation and techniques that are not based on correlation.

DCT-domain watermarking techniques for still images: detector performance analysis and a new structure

Abstract: A spread-spectrum-like discrete cosine transform (DCT) domain watermarking technique for copyright protection of still digital images is analyzed. The DCT is applied in blocks of 8/spl times/8 pixels, as in the JPEG algorithm. The watermark can encode information to track illegal misuses. For flexibility purposes, the original image is not necessary during the ownership verification process, so it must be modeled by noise. Two tests are involved in the ownership verification stage: watermark decoding, in which the message carried by the watermark is extracted, and watermark detection, which decides whether a given image contains a watermark generated with a certain key. We apply generalized Gaussian distributions to statistically model the DCT coefficients of the original image and show how the resulting detector structures lead to considerable improvements in performance with respect to the correlation receiver, which has been widely considered in the literature and makes use of the Gaussian noise assumption. As a result of our work, analytical expressions for performance measures, such as the probability of errors in watermark decoding and the probabilities of false alarms and of detection in watermark detection, are derived and contrasted with experimental results.

Information-theoretic analysis of information hiding

Abstract: An information-theoretic analysis of information hiding is presented, forming the theoretical basis for design of information-hiding systems. Information hiding is an emerging research area which encompasses applications such as copyright protection for digital media, watermarking, fingerprinting, steganography, and data embedding. In these applications, information is hidden within a host data set and is to be reliably communicated to a receiver. The host data set is intentionally corrupted, but in a covert way, designed to be imperceptible to a casual analysis. Next, an attacker may seek to destroy this hidden information, and for this purpose, introduce additional distortion to the data set. Side information (in the form of cryptographic keys and/or information about the host signal) may be available to the information hider and to the decoder. We formalize these notions and evaluate the hiding capacity, which upper-bounds the rates of reliable transmission and quantifies the fundamental tradeoff between three quantities: the achievable information-hiding rates and the allowed distortion levels for the information hider and the attacker. The hiding capacity is the value of a game between the information hider and the attacker. The optimal attack strategy is the solution of a particular rate-distortion problem, and the optimal hiding strategy is the solution to a channel-coding problem. The hiding capacity is derived by extending the Gel'fand-Pinsker (1980) theory of communication with side information at the encoder. The extensions include the presence of distortion constraints, side information at the decoder, and unknown communication channel. Explicit formulas for capacity are given in several cases, including Bernoulli and Gaussian problems, as well as the important special case of small distortions. In some cases, including the last two above, the hiding capacity is the same whether or not the decoder knows the host data set. It is shown that many existing information-hiding systems in the literature operate far below capacity.

Watermarking schemes evaluation

Abstract: In this article we have used a duality approach to the watermarking evaluation problem by splitting the evaluation criteria into two (independent) groups: functionality and assurance. The first group represents a set of requirements that can be verified using agreed series of tests; the second is a set of levels to which each functionality is evaluated. These levels go from zero or low to very high. We are investigating how evaluation profiles can be defined for different applications and how importance sampling techniques could be used to evaluate the false alarm rate in an automated way.

Robust template matching for affine resistant image watermarks

Abstract: Digital watermarks have been proposed as a method for discouraging illicit copying and distribution of copyrighted material. This paper describes a method for the secure and robust copyright protection of digital images. We present an approach for embedding a digital watermark into an image using the Fourier transform. To this watermark is added a template in the Fourier transform domain to render the method robust against general linear transformations. We detail a new algorithm based on polar maps for the accurate and efficient recovery of the template in an image which has undergone a general affine transformation. We also present results which demonstrate the robustness of the method against some common image processing operations such as compression, rotation, scaling, and aspect ratio changes.

Watermarking digital image and video data

Abstract: A chuck has a chuck body rotatable about an axis and formed with a plurality of angularly spaced radially extending inner guides and a plurality of angularly spaced and radially extending outer guides. An inner jaw part wholly received within the chuck body is radially displaceable in each of the inner guides and an outer jaw part projecting axially from the chuck body is radially displaceable in each of the outer guides. An operating element is engaged with all of the inner jaw parts to jointly radially displace them. A coupling member is axially displaceable in each of the inner jaw parts between a coupling position in which each of the inner parts is locked for joint radial movement with the respective outer part and an axially offset decoupling position allowing relative radial displacement of the outer jaw parts and the respective inner jaw parts. These coupling members may be independently operable, or jointly operable by means of a cam ring.

Counterfeiting attacks on oblivious block-wise independent invisible watermarking schemes

Abstract: We describe a class of attacks on certain block-based oblivious watermarking schemes. We show that oblivious watermarking techniques that embed information into a host image in a block-wise independent fashion are vulnerable to a counterfeiting attack. Specifically, given a watermarked image, one can forge the watermark it contains into another image without knowing the secret key used for watermark insertion and in some cases even without explicitly knowing the watermark. We demonstrate successful implementations of this attack on a few watermarking techniques that have been proposed in the literature. We also describe a possible solution to this problem of block-wise independence that makes our attack computationally intractable.

Robust hash functions for digital watermarking

Abstract: Digital watermarks have been proposed for authentication of both video data and still images and for integrity verification of visual multimedia In such applications, the watermark has to depend on a secret key and on the original image It is important that the dependence on the key be sensitive, while the dependence on the image be continuous (robust) Both requirements can be satisfied using special image digest functions that return the same bit-string for a whole class of images derived from an original image using common processing operations It is further required that two completely different images produce completely different bit-strings We discuss methods how such robust hash functions can be built We also show how the hash bits has another application, the robust image digest can be used as a search index for an efficient image database search

A robust DCT-based watermarking for copyright protection

Abstract: A novel technique for embedding watermarks into a host image in the frequency domain is proposed. Unlike the traditional techniques, the method addresses that the watermark is embedded at low frequency. The weighted correction is also used to improve the imperceptibility of the watermark. Moreover the watermark is self-extractable and the algorithm is simple. Experimental results demonstrate that the watermark is robust to various attacks.

On the Gaussian watermarking game

Abstract: Watermarking models a copyright protection mechanism where an original source sequence or "covertext" is modified before distribution to the public in order to embed some extra information. The embedding should be transparent (i.e., the modified data sequence or "stegotext" should be similar to the covertext) and robust (i.e., the extra information should be recoverable even if the stegotext is modified further, possibly by a malicious "attacker"). We compute the coding capacity of the watermarking game for a Gaussian covertext and squared-error distortions. Both the public version of the game (covertext known to neither attacker nor decoder) and the private version of the game (covertext unknown to attacker but known to decoder) are treated. While the capacity of the former cannot, of course, exceed the capacity of the latter, we show that the two are, in fact, identical. These capacities depend critically on whether the distortion constraints are required to be met in expectation or with probability one. In the former case, the coding capacity is zero, whereas in the latter it coincides with the value of related zero-sum dynamic mutual information games of complete and perfect information. We also compute the capacity when the attacker is restricted to additive attacks. This capacity turns out to be strictly larger than the watermarking capacity, thus demonstrating that additive attacks are suboptimal. In fact, under the additive attack restriction, capacity turns out to coincide with the capacity of Costa's (1983) model for "writing on dirty paper," thus demonstrating that in Costa's model, the independent and identically distributed (i.i.d.) Gaussian "noise" is the most malevolent power-limited "noise". Additionally, Costa's observation that in the presence of i.i.d. Gaussian "noise," an i.i.d. Gaussian "dirt" process that is noncausally known to the transmitter (but not receiver) does not reduce capacity, is extended to general ergodic "dirt" and to stationary (but not necessarily white) Gaussian "noise".

Digital rights management and watermarking of multimedia content for m-commerce applications

Abstract: E-commerce has become a huge business and a driving factor in the development of the Internet. Online shopping services are well established and will, with the advent of evolved 2G and 3G mobile networks, soon be complemented by their wireless counterparts. Furthermore, online delivery of digital media, such as MP3 audio or video, is very popular today and will become an increasingly important part of e-commerce and mobile e-commerce (m-commerce). However, a major obstacle for digital media distribution and associated business is the possibility of unlimited consecutive copying in the digital domain, which threatens intellectual property rights (e.g., copyrights). Digital rights management systems are required to protect rights and business. DRM systems typically incorporate encryption, conditional access, copy control mechanisms, and media identification and tracing mechanisms. Watermarking is the technology used for copy control and media identification and tracing. Most proposed watermarking methods use a so-called spread spectrum approach: a pseudo-noise signal with small amplitude is added to the host signal, and later on detected using correlation methods. A secret key is used to ensure that the watermark can only be detected and removed by authorized parties. Thus, watermarking is an essential component of modern DRM systems. Several standardization bodies are involved in DRM standardization. Some examples, (MPEG-4, SDMI, and DVD), are discussed in this article. Watermarking as an enabling technology is especially highlighted. Furthermore, the relation between DRM and m-commerce, and the impact on business models for m-commerce are discussed. A common experience today is that Internet e-commerce applications cannot always easily be adapted for mobile telecommunications systems. We emphasize, however, that DRM and watermarking can benefit from the additional information available in mobile telecommunications systems, and can thus help to improve rights management for digital media delivery.

Relevance of watermarking in medical imaging

Abstract: Because of the importance of the security issues in the management of medical information, we suggest the use of watermarking techniques to complete the existing measures for protecting medical images. We discuss the necessary requirements for such a system to be accepted by medical staff and its complementary role with respect with existing security systems. We present different scenarios, one devoted to the authentication and tracing of the images, the second to the integrity control of the patient's record.

Embedding image watermarks in dc components

Abstract: Both watermark structure and embedding strategy affect robustness of image watermarks. Where should watermarks be embedded in the discrete cosine transform (DCT) domain in order for the invisible image watermarks to be robust? Though many papers in the literature agree that watermarks should be embedded in perceptually significant components, dc components are explicitly excluded from watermark embedding. In this letter, a new embedding strategy for watermarking is proposed based on a quantitative analysis on the magnitudes of DCT components of host images. We argue that more robustness can be achieved if watermarks are embedded in dc components since dc components have much larger perceptual capacity than any ac components. Based on this idea, an adaptive watermarking algorithm is presented. We incorporate the feature of texture masking and luminance masking of the human visual system into watermarking. Experimental results demonstrate that the invisible watermarks embedded with the proposed watermark algorithm are very robust.

Watermarking applications and their properties

Abstract: We describe a number of applications of digital watermarking and we examine the common properties of robustness, tamper resistance, fidelity, computational cost and false positive rate. We observe that these properties vary greatly depending on the application. Consequently, we conclude that evaluation of a watermarking algorithm is difficult without first indicating the context in which it is to be applied.

Watermark copy attack

Abstract: Research in digital watermarking has progressed along two paths. While new watermarking technologies are being developed, some researchers are also investigating different ways of attacking digital watermarks. Common attacks to watermarks usually aim to destroy the embedded watermark or to impair its detection. In this paper we propose a conceptually new attack for digitally watermarked images. The proposed attack does not destroy an embedded watermark, but copies it from one image to a different image. Although this new attack does not destroy a watermark or impair its detection, it creates new challenges, especially when watermarks are used for copyright protection and identification. The process of copying the watermark requires neither algorithmic knowledge of the watermarking technology nor the watermarking key. The attack is based on an estimation of the embedded watermark in the spatial domain through a filtering process. The estimate of the watermark is then adapted and inserted into the target image. To illustrate the performance of the proposed attack we applied it to commercial and non-commercial watermarking schemes. The experiments showed that the attack is very effective in copying a watermark from one image to a different image. In addition, we have a closer look at application dependent implications of this new attack.

Detection of image alterations using semifragile watermarks

Abstract: Digital watermarking research has generally focused upon two classes of watermarks, fragile and robust. Robust watermarks are designed to be detected even after attempts are made to remove them. Fragile watermarks are used for authentication purposes and are capable of detecting even minute changes of the watermarked content. Unfortunately, neither type of watermark is ideal when considering 'information preserving' transformations (such as compression) which preserve the meaning or expression of the content and 'information altering' transformations (such as feature replacement) which change the expression of the content. In this paper we describe a semi-fragile watermark for still images that can detect information altering transformations even after the watermarked content is subjected to information preserving alterations.

Audio watermarking: features, applications and algorithms

Abstract: This paper considers the desired properties and possible applications of audio watermarking algorithms. Special attention is given to statistical methods working in the Fourier domain. It presents a solution to robust watermarking of audio data and reflects the security properties of the technique. Experimental results show good robustness of the approach against MP3 compression and other common signal processing manipulations. Enhancements to the presented methods are discussed.

Cocktail watermarking for digital image protection

Abstract: A novel image protection scheme called "cocktail watermarking" is proposed in this paper. We analyze and point out the inadequacy of the modulation techniques commonly used in ordinary spread spectrum watermarking methods and the visual model-based ones. To resolve the inadequacy, two watermarks which play complementary roles are simultaneously embedded into a host image. We also conduct a statistical analysis to derive the lower bound of the worst likelihood that the better watermark (out of the two) can be extracted. With this "high" lower bound, it is ensured that a "better" extracted watermark is always obtained. From extensive experiments, results indicate that our cocktail watermarking scheme is remarkably effective in resisting various attacks, including combined ones.

Information Hiding: Steganography and Watermarking-Attacks and Countermeasures: Steganography and Watermarking - Attacks and Countermeasures

Abstract: Information Hiding: Steganography and Watermarking - Attacks and Countermeasures deals with information hiding. With the proliferation of multimedia on the Internet, information hiding addresses two areas of concern: privacy of information from surveillance (steganography) and protection of intellectual property (digital watermarking). Steganography (literally, covered writing) explores methods to hide the existence of hidden messages. These methods include invisible ink, microdot, digital signature, covert channel, and spread spectrum communication. Digital watermarks represent a commercial application of steganography. Watermarks can be used to track the copyright and ownership of electronic media. In this volume, the authors focus on techniques for hiding information in digital media. They analyze the hiding techniques to uncover their limitations. These limitations are employed to devise attacks against hidden information. The goal of these attacks is to expose the existence of a secret message or render a digital watermark unusable. In assessing these attacks, countermeasures are developed to assist in protecting digital watermarking systems. Understanding the limitations of the current methods will lead us to build more robust methods that can survive various manipulation and attacks. The more information that is placed in the public's reach on the Internet, the more owners of such information need to protect themselves from theft and false representation. Systems to analyze techniques for uncovering hidden information and recover seemingly destroyed information will be useful to law enforcement authorities in computer forensics and digital traffic analysis. Information Hiding: Steganography and Watermarking - Attacks and Countermeasures presents the authors' research contributions in three fundamental areas with respect to image-based steganography and watermarking: analysis of data hiding techniques, attacks against hidden information, and countermeasures to attacks against digital watermarks. Information Hiding: Steganography and Watermarking e Attacks and Countermeasures is suitable for a secondary text in a graduate level course, and as a reference for researchers and practitioners in industry.

Data hiding in digital binary image

Abstract: This paper proposes a new method to embed data in binary images, including scanned text, figures and signatures. The method manipulates "flippable" pixels and uses shuffling to embed a significant amount of data without causing noticeable artifacts. The extraction of the hidden data does not require the original image. Potential applications include detecting unauthorized use of a digitized signature and authenticating binary documents.

Digital watermarking employing both frail and robust watermarks

Abstract: Image, video, or audio data is encoded with both a frail and a robust watermark The two watermarks respond differently to different forms of processing (eg, copying the object may render the frail watermark unreadable), permitting an original object to be distinguished from a processed object Appropriate action can then taken in response thereto

Applications for data hiding

Abstract: In an earlier paper, "Techniques for Data Hiding," the overall goals and constraints of information-hiding problem space and a variety of approaches to information hiding in image, audio, and text were described. In this sequel, information-hiding goals and applications are expanded beyond watermarking to encompass the more general concept of information tagging. As a framework for illustrating these concepts, multiple-bit and midlevel image-representation information-hiding techniques are described. A range of applications, including anticounterfeiting and authentication, is explored.

Image processing apparatus and method, and storage medium

Abstract: An image processing apparatus and method for deriving a digital watermark embedded in an image is provided which has a recognizing unit for recognizing a predetermined characteristic area in the image and a deriving unit for extracting the digital watermark from the image data in the recognized characteristic area.

Multiple watermarking techniques for documents and other data

Abstract: Multiple digital watermarks, each of which has different characteristics, are embedded in a document. The characteristics of the various watermarks are chosen so that each of the watermarks will be affected in a different manner if the document is subsequently copied and reproduced. The detection process or mechanism reads each of the watermark and compares their characteristics. While wear and handling may change the characteristics of the digital watermarks in a document, the relationship between the characteristic of multiple digital watermarks in a document will never-the-less give an indication as to whether a document is an original or a copy of an original.

The Watermark Copy Attack

Abstract: Research in digital watermarking has progressed along two paths. While new watermarking technologies are being developed, some researchers are also investigating different ways of attacking digital watermarks. Common attacks to watermarks usually aim to destroy the embedded watermark or to impair its detection. In this paper we propose a conceptually new attack for digitally watermarked images. The proposed attack does not destroy an embedded watermark, but copies it from one image to a different image. Although this new attack does not destroy a watermark or impair its detection, it creates new challenges, especially when watermarks are used for copyright protection and identification. The process of copying the watermark requires neither algorithmic knowledge of the watermarking technology nor the watermarking key. The attack is based on an estimation of the embedded watermark in the spatial domain through a filtering process. The estimate of the watermark is then adapted and inserted into the target image. To illustrate the performance of the proposed attack we applied it to commercial and non-commercial watermarking schemes. The experiments showed that the attack is very effective in copying a watermark from one image to a different image. In addition, we have a closer look at application dependent implications of this new attack.

A DCT domain visible watermarking technique for images

Abstract: The growth of computer networks has boosted the growth of the information technology sector to a greater extent. There is a trend to move from conventional libraries to digital libraries. In digital libraries images and text are made available through the Internet for scholarly research. At the same time care is taken to prevent the unauthorized use of the images commercially. In some cases the observer is encouraged to patronize the institution that owns the material. To satisfy both these needs simultaneously the owner needs to use visible watermarking. Visible watermarking is a type of digital watermarking used for protection of publicly available images. We describe a visible watermarking scheme that is applied into the host image in the DCT domain. A mathematical model has been developed for this purpose. We also propose a modification of the algorithm to make the watermark more robust.

A blind watermarking scheme based on structured codebooks

Abstract: Blind digital watermarking is the communication of information via multimedia host data, where the unmodified host data is not available to the watermark detector. Many watermarking schemes suffer considerably from the remaining host-signal interference. For the additive white Gaussian case, M.H.M. Costa (1983) showed theoretically that interference from the host can be eliminated. However, the proof involves a huge, unstructured, random codebook, which is not feasible in practical systems. We present a suboptimal, practical scheme that employs a lattice-structured codebook to reduce complexity. The performance of the proposed scheme is compared to the information-theoretic limit and similar recent proposals.

Removal of fixed pattern noise and other fixed patterns from media signals

Abstract: A method of removing fixed pattern noise derives an estimate of fixed pattern noise from a composite media signal and uses the estimate to evaluate and remove fixed pattern noise from selected frames. The technique is particularly suited for removing fixed pattern noise in images due to image capture processes, but applies to other media signals as well. In watermarking applications, the method can be used to improve detection and recovery of a watermark. Also, it may be used to remove components of a watermark or a watermark from a cover signal that contains two or more different watermarks.