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

Trends in extreme learning machines

Currently, the most successful approach to steganography in empirical objects, such as digital media, is to embed the payload while minimizing a suitably defined distortion function. The design of the distortion is essentially the only task left to the steganographer since efficient practical codes exist that embed near the payload-distortion bound. The practitioner’s goal is to design the distortion to obtain a scheme with a high empirical statistical detectability. In this paper, we propose a universal distortion design called universal wavelet relative distortion (UNIWARD) that can be applied for embedding in an arbitrary domain. The embedding distortion is computed as a sum of relative changes of coefficients in a directional filter bank decomposition of the cover image. The directionality forces the embedding changes to such parts of the cover object that are difficult to model in multiple directions, such as textures or noisy regions, while avoiding smooth regions or clean edges. We demonstrate experimentally using rich models as well as targeted attacks that steganographic methods built using UNIWARD match or outperform the current state of the art in the spatial domain, JPEG domain, and side-informed JPEG domain.

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Universal distortion function for steganography in an arbitrary domain

This paper presents a complete methodology for designing practical and highly-undetectable stegosystems for real digital media. The main design principle is to minimize a suitably-defined distortion by means of efficient coding algorithm. The distortion is defined as a weighted difference of extended state-of-the-art feature vectors already used in steganalysis. This allows us to "preserve" the model used by steganalyst and thus be undetectable even for large payloads. This framework can be efficiently implemented even when the dimensionality of the feature set used by the embedder is larger than 107. The high dimensional model is necessary to avoid known security weaknesses. Although high-dimensional models might be problem in steganalysis, we explain, why they are acceptable in steganography. As an example, we introduce HUGO, a new embedding algorithm for spatial-domain digital images and we contrast its performance with LSB matching. On the BOWS2 image database and in contrast with LSB matching, HUGO allows the embedder to hide 7× longer message with the same level of security level.

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Using high-dimensional image models to perform highly undetectable steganography

This paper presents a reversible or lossless watermarking algorithm for images without using a location map in most cases. This algorithm employs prediction errors to embed data into an image. A sorting technique is used to record the prediction errors based on magnitude of its local variance. Using sorted prediction errors and, if needed, though rarely, a reduced size location map allows us to embed more data into the image with less distortion. The performance of the proposed reversible watermarking scheme is evaluated using different images and compared with four methods: those of Kamstra and Heijmans, Thodi and Rodriguez, and Lee et al. The results clearly indicate that the proposed scheme can embed more data with less distortion.

Reversible Watermarking Algorithm Using Sorting and Prediction

Developments in multimedia technology over the past decade has caused video-on-demand services to emerge as a new paradigm in home entertainment. Because of the large volume of data involved in the process and stringent continuity and real-time constraints, these services pose challenges that are different from the standard file transfer operations in the network. The necessity of efficient usage of scarce resources like network bandwidth and server capacity (in terms of I/O bandwidth) demands novel and easy-to-use schemes for scheduling continuous video streams. This paper presents an overview of the major scheduling policies that have emerged in the recent past. In particular, the paper provides detailed discussion on policies based on principles of broadcasting, batching, caching, and piggybacking or merging. Policies like look-ahead scheduling schemes that are designed exclusively to provide certain interactive VCR-like control operations are also covered. A conceptual comparison between the various classes of scheduling policies is carried out to identify common threads and key concepts. Performance of these policies in terms of bandwidth demand reduction, customer waiting time reduction, provision of interactive control by the user, and fairness of service are given special emphasis. The paper concludes with a discussion on the possible avenues of further reasearch and development in this potentially interesting and challenging field.

Scheduling Video Streams in Video-on-Demand Systems: A Survey

An improved section-wise exploiting modification direction method

Recently, reversible data hiding (RDH) techniques for JPEG images have become more extensively used to combine image and authentication information conveniently into one file. Although embedding data in JPEG image degrades visual quality and increases file size, it is proven to be useful for data communication and image authentication. In this paper, a data hiding method in JPEG image using a new coefficient selection technique is proposed. The proposed scheme embeds data using the histogram shifting (HS) method. According to the number of zero AC coefficients, block ordering is used to embed data first in the blocks causing less distortion. In order to further reduce the distortion, positions of AC coefficients are selected carefully. Finally, AC coefficients valued +1 and −1 are used for embedding, and the remaining non-zero AC coefficients are shifted to the left or right directions according to their sign. Compared to the current state-of-the-art method, experimental results show that the proposed method has higher peak signal to noise ratio (PSNR) and smaller file size.

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Improved reversible data hiding in JPEG images based on new coefficient selection strategy

This paper presents an improved data hiding technique based on BCH (n,k,t ) coding. The proposed embedder hides data into a block of input data by modifying some coefficients in the block in order to null the syndrome. The proposed embedder can hide data with less computational time and less storage capacity compared to the existing methods. The complexity of the proposed method is linear while that of other methods are exponential for any block size n. Thus, it is easy to extend this method to a large n. The BCH syndrome coding for steganography is now viable ascribed to the reduced complexity and its simplicity of the proposed embedder.

Hyoung Joong Kim

Papers

Scheduling Video Streams in Video-on-Demand Systems: A Survey

An improved section-wise exploiting modification direction method

Improved reversible data hiding in JPEG images based on new coefficient selection strategy

An Efficient Embedder for BCH Coding for Steganography

Load Partitioning and Trade-Off Study for Large Matrix-Vector Computations in Multicast Bus Networks with Communication Delays