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.

Recently, we proposed a method for constructing a template for efficient temporal synchronization in video watermarking.1 Our temporal synchronization method uses a state machine key generator for producing the watermark embedded in successive frames of video. A feature extractor allows the watermark key schedule to be content dependent, increasing the difficulty of copy and ownership attacks. It was shown that efficient synchronization can be achieved by adding temporal redundancy into the key schedule. In this paper, we explore and extend the concepts of our temporal synchronization method to spatial synchronization. The key generator is used to construct the embedded watermark of non-overlapping blocks of the video, creating a tiled structure.2

In the past decade there has been an explosion in the use and distribution of digital multimedia data. PCs with Internet connections have taken homes by storm and have made the distribution of multimedia data and applications much easier and faster. Electronic commerce applications and on-line services are rapidly being developed. Even the analog audio and video equipment in the home is in the process of being replaced by their digital successors. As a result, we can see the digital mass recording devices for multimedia data enter the consumer market of today.

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 of multimedia content has become a very active research area over the last several years. A general framework for watermark embedding and detection/decoding is presented here along with a review of some of the algorithms for different media types described in the literature. We highlight some of the differences based on application such as copyright protection, authentication, tamper detection, and data hiding as well as differences in technology and system requirements for different media types such as digital images, video, audio and text.

When looked at as a communication task, the watermarking process can be split into three main steps: watermark generation and embedding (information transmission), possible attacks (transmission through the channel), and watermark retrieval (information decoding at the receiver side). In this article we review the main issues in watermark generation and embedding. By focusing on the case of image watermarking, we first discuss the choice of the image features the watermark is superimposed to. Then wc consider watermark generation and the rule used to insert the watermark within the host features. By adopting again a communication perspective, some useful hints are given on the way the watermark should be shaped and inserted within the host document for increased robustness against attacks. Given that invisibility is one of the main requirements a watermark must satisfy, the way psycho-visual notions can be used to effectively hide the watermark within an image is carefully rcviewed in the second part of the article. Rather than insisting on the mathematical aspects of each of the above issues, the main rationale behind the most commonly adopted approaches is given, as well as some illustrative examples.

Digital multimedia content is delivered to homes via the Internet, satellite, terrestrial and cable networks. Scrambling is a common approach used by conditional access systems to prevent unauthorized access to audio/ visual data. The descrambling keys are securely distributed to the receivers in the same transmission channel. Their protection is an important part of the key management problem. Although public-key cryptography provides a viable solution, alternative methods are sought for economy and emcieney. Message authentication is an important objective of information security in modern electronic distribution networks. This objective is met by providing the receiver of a message an assurance of the sender’s identity. As physical protection such as sealed envelopes is not possible for messages expressed as binary sequences, digital tools have been developed using cryptography, A major limitation of all cryp tographic methods for message authentication lies in their use of algorithms with flxed symmetric or public keys. This paper presents a key transport protocol based on secret sharing. Conditional access and message authentication are two important application areas for which the advantages of the proposed protocol are discussed. The protocol eliminates the need for a cipher, yet effectively combines the advantages of symmetric and public-key ciphers. It can be used to build a new key management scheme that allows the service providers to generate different keys for different sets of receivers, and to renew these keys in a convenient way.

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.