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  In this paper we describe methods for forensic charac- terization of devices. This is important in verifying the trust and authenticity of data and the device that created it. We will present and examine current forensic identica- tion techniques for RF devices, printers, cameras, and show how these techniques can be generalized for use with other devices.

In this paper we will overview the use of data hiding techniques in digital images. In particular we will describe how one can use Steganography to hide information in a digital image. Steganography is related to cryptography and is the basis for many of the digital watermarking techniques currently being developed. The interest in data hiding has risen with the recent activity in digital copyright protection schemes. One way to protect the ownership of a digital image is to secretly embed data in the content of the image identifying the owner. This paper will review recent developments in data hiding, specifically as it pertains to copyright protection of digital images.

Many image watermarks have been proposed to protect intellectual property in an age where digital images may be easily modified and perfectly reproduced. In a fragile marking system, a signal (watermark) is embedded within an image such that subsequent alterations to the watermarked image can be detected with high probability. The insertion of the watermark is perceptually invisible under normal human observation. These types of marks have found applicability in image authentication systems. In this paper we discuss fragile marking systems and their desirable features, common methods of attack, and survey some recent marking systems.

A digital home network is a cluster of digital audio/visual (A/V) devices including set-top boxes, TVs, VCRs, DVD players, and general-purpose computing devices such as personal computers. The network may receive copyrighted digital multimedia content from a number of sources. This content may be broadcast via satellite or terrestrial systems, transmitted by cable operators, or made available as prepackaged media (e.g., a digital tape or a digital video disc). Before releasing their content for distribution, the content owners may require protection by specifying access conditions. Once the content is delivered to the consumer, it moves across home the network until it reaches its destination where it is stored or displayed. A copy protection system is needed to prevent unauthorized access to bit streams in transmission from one A/V device to another or while it is in storage on magnetic or optical media. Recently, two fundamental groups of technologies, encryption and watermarking, have been identified for protecting copyrighted digital multimedia content. This paper is an overview of the work done for protecting content owners

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.

Video streaming, or the real-time delivery of video over a data network, is the underlying technology behind many applications including video conferencing, video-on-demand, and the delivery of educational and entertainment content. In many applications, particularly ones involving entertainment content, security issues, such as conditional access and copy protection must be addressed. To resolve these security issues, techniques that include encryption and watermarking need to be developed. Since the video sequences will often be compressed using a scalable compression technique and transported over a lossy packet network using the Internet Protocol (IP), the security techniques must be compatible with the compression method and data transport and be robust to errors. In this paper, we address the issues involved in the watermarking of rate-scalable video streams delivered using a practical network. Watermarking is the embedding of a signal (the watermark) into a video stream that is imperceptible when the stream is viewed but can be detected by a watermark detector. Many watermarking techniques have been proposed for digital images and video, but the issues of streaming have not been fully investigated. A review of streaming video is presented, including scalable video compression and network transport, followed by a brief review of video watermarking and the discussion of watermarking streaming video.

With the advent of digital technologies, many new market opportunities have emerged for content owners, content distributors, and consumer electronics/information technology industries. An essential requirement for developing a thriving marketplace is the protection of copyrighted content in digital form. There are four major stages in the delivery of content to the consumer: (1) capturing on digital media, (2) packaging, (3) distribution to home networks, and (4) transfer to the final audio/visual device within the home network. Entertainment content is of particular importance as it will be in high demand for many years to come. If an end-to-end security cannot be provided in a digital market, there would be no incentive for content creation. Lack of new supplies would result in detrimental effects for all the industries involved in the delivery chain. In this paper, we present the primary means of securing the entertainment content from creation to consumption in an attempt to understand the overall complexity of the problem.

Scalability has become an important feature for video coding algorithm desip for heterogeneous networks due to variable bandwidth, variable wired and wireless network conditions and variable terminal capabilities However, the best video compression algorithms are based on temporal prediction through motion compensation which do not lend themselves naturally to a scalable framework More recently, hybrid coding schemes have been introduced that combine a base-layer motion-compensation coder with an enhancement layer which offers fine-grain scalability through an embedded or progressive coder Such a framework usually results in some compression efficiency loss over the best single layer motion compensated scheme Here, we introduce a hybrid coding scheme which combines a baselayer MC coder and a finely scalable enhancement layer where the information from the base-layer is used to determine the location of the high energy signal in the enhancement layer. This coder provides better compression results than embedded approaches which do not rely on base layer information.

One of the challenges for blind watermark detection is synchronization. Synchronization is the process of identifying the coordinates of an embedded watermark and is crucial in successful watermark detection. If the detector

This paper overviews the problems with temporal synchronization in video watermarking and describes a new approach for efficient synchronization and resynchronization. A complete version of the new method is presented in [1].

Scalable video compression is the encoding of a single video stream in multiple layers, each layer with its own bit rate. Because of the computational complexity of full video encryption, partial encryption has emerged as a general trend for both standard and scalable video codecs. Depending on the application, a particular layer of the video stream is chosen for encryption. In some applications, however, more than one video layer may need to be protected. This results in a more complicated key management as multiple keys are needed. In this paper, we present an integrated approach to encrypting multiple layers. Our proposal is a prepositioned shared secret cheme that enables the reconstruction of different keys by communicating different activating shares for the same prepositioned information. It presents certain advantages over three other key management schemes.

In [1], we proposed a technique or protocol for efficient temporal synchronization of video watermarks. Our technique is based on constructing a watermark with temporal redundancy, which allows the detector to efficiently establish and maintain synchronization without performing extensive search or explicit template signal embedding. In this paper, we describe several enhancements to our technique. A new class of key generators is presented which uses a cryptographic hash function to define the set of states and the state transition function of the finite state machine (FSM). In addition to the very large number of states and key-dependent state transition functions, which enhance security, the new class of key generators allows a limited degree of randomization. This randomization can take the form of multiple start states in the FSM, or by randomized state transitions. The non-deterministic behavior of a randomized FSM requires the detector to perform more search, but also makes the key sequence less predictable and improves security. We also describe a new method for temporal redundancy control which adaptively changes the watermark key based on the characteristics of the video. This new strategy prevents a loss of temporal redundancy (which leads to a loss of robustness) which can occur using the earlier na

Security is an increasingly important attribute for multimedia applications that require prevention of unauthorized access to copyrighted data. Two approaches have been used to protect scalable video content in distribution: Partial encryption and progressive encryption. Partial encryption provides protection for only selected portions of the video. Progressive encryption allows transcoding with simple packet truncation, and eliminates the need to decrypt the video packets at intermediate network nodes with low complexity. Centralized Key Management with Secret Sharing (CKMSS) is a recent approach in which the group manager assigns unique secret shares to the nodes in the hierarchical key distribution tree. It allows the reconstruction of different keys by communicating different activating shares for the same prepositioned information. Once the group key is established, it is used until a member joins/leaves the multicast group or periodic rekeying occurs. In this paper, we will present simulation results regarding the communication, storage and processing requirements of the CKMSS scheme applied to scalable video. In particular, we have measured the rekey message sizes, storage capacity, and processing times needed by the server for each join/leave request and periodic rekey event.

A robust, invisible watermarking scheme is proposed for digital images, where the watermark is embedded using the block-based Lapped Orthogonal Transform (LOT). The embedding process follows a spread spectrum watermarking approach. In contrast to the use of transforms such as DCT, our LOT watermarking scheme allows larger watermark embedding energy while maintaining the same level of subjective invisibility. In particular, the use of LOT reduces block artifacts caused by the insertion of the watermark in a block-by-block manner, hence obtaining a better balance between invisibility and robustness. Moreover, we use a human visual system (HVS) model to adaptively adjust the energy of the watermark during embedding. In our HVS model, each block is categorized into one of four classes (texture, fine-texture, edge, and plain-area) by using a feature known as the Texture Masking Energy (TME). Blocks with edges are also classified according to the edge direction. The block classification is used to adjust the watermark embedding parameters for each block.