An SDMI-based Rights Management Systems for Electronic Media Using Digital Watermarking

Transcription

1 An SDMI-based Rights Management Systems for Electronic Media Using Digital Watermarking S. H. Kwok, C.C. Yang, K.Y. Tam, and Jason S.W. Wong Department of Information and Systems Management The Hong Kong University of Science and Technology, Hong Kong Phone: (852) Fax: (852) Department of Systems Engineering and Engineering Management The Chinese University of Hong Kong, Hong Kong Phone: (852) Fax: (852) Department of Information and Systems Management The Hong Kong University of Science and Technology, Hong Kong Phone: (852) Fax: (852) Department of Systems Engineering and Engineering Management The Chinese University of Hong Kong, Hong Kong Abstract Building rights management syste6ms for electronic commerce is still a complex task, as they may need to manage a large set of different media, rights, and technologies. Recently Secure Digital Music Initiative (SDMI) was proposed to provide a secured environment for music distribution through Internet, in which rights management is a concern and is implemented using digital watermarking. However, SDMI does not provide the guidelines of how to design digital watermark for rights management. This paper tries to fill this gap in proposing an SDMI-based rights management systems to support other electronic media, including video, and discussing the design of digital watermark for rights management. This paper also applies digital watermarking for marketing application in the proposed rights management system. The proposed rights management system is a client/server system, which is composed of three major functional components; rights management system (RMS) server, rights management database (RMDB), and multimedia player (MP). The functions of the proposed rights management system cover a wide range of aspects, including, copyright protection, usage control, access rights control, and marketing. The main aspects in the design are discussed. A prototype of the SDMI-based rights management system was developed and the interfaces of major component are presented in this paper. Keywords: rights management, digital watermarking, copyrights protection, intellectual property protection, electronic commerce. Introduction This decade has witnessed an explosion in the distribution of electronic digital publishing via media such as compact discs (CD-ROMs) and digital video discs (DVDs) and digital television. However, digital technology has also made copying and distributing illegal copies of copyrightprotected material fast, easy and cheap. In order to combat the potentially disastrous losses to the revenue, the major owners and distributors of copyright electronic media, such as image libraries, music and film industries and online publishers, have sought ways to detect and prevent copyright infringement. Thus, rights management becomes a very important concern to the content providers for rights verifications, ownership identification, copyright protection, and control of rights to access. Rights management, in general, refers to the problems associated with intellectual property rights, including copy protection, and in particular to the problem of assuring that, in a commerce setting, payment is made for a particular use of content, and that the use made does not exceed the use authorized [7]. Digital watermarking is regarded as a tool for rights management. T. Page [5] treats digital watermarking as a form of rights management in the protection and authentication of digital images, audio, video files, and he also addressed their relationships in his article. Digital watermarking basically adds information which is normally invisible or barely visible to the human eyes or human ears,

2 but which can be detected in order to identify the authenticity or copyright owner of the media. Until now, there is no International standard to govern the rights management or intellectual property protection using digital watermarking. Solutions found in the literature are towards different applications and services, with their own rules, regulations, and approaches. In academic study of rights management, researchers tend to focus on individual functional components. Key components include, license management, public key infrastructure [9], and watermarking [1]. The DPRI project ( Digital Property Rights Infrastructure - music and publishing industry online copyright protection and content distribution ) is a project to address specifically copyright issues in music distribution by the Hong Kong University of Science and Technology. The project is funded by the Hong Kong SAR Government under the Industrial Support Fund (ISF) Scheme. The first stage of the DPRI project was just completed. Some studies on copyright protection for distributed music using audio watermarking were achieved and empirical results show that digital watermarking can benefit not only copyright management but also rights management in electronic commerce. This paper is part of the project findings. Commercial rights management suites and solutions using digital watermarking are also found in the market. Here is a review of some relevant commercial rights management solutions. Digimarc TM [2] is a digital watermarking technology, which can be used in a wide variety of digital visual contents, both image and video media. The Digimarc TM provides for visual content owners a range of solutions including copyright communication, image licensing and management, and enhanced Internet commerce. These solutions are enabled by a set of digital watermarking tools that embed, read and respond to the watermarks as they enable new communications capabilities within digital visual content. The InterTrust Commerce Architecture [4], principally based on DigiBox TM secure containers, InterTrust Commerce Nodes and a secure operating system layer extension, enables the creation of a globally distributed Intertrustworthy TM environment. This environment provides the basis for the broad range of real-world rights and obligations, including intellectual property rights, and real-world rules related to those rights and obligations, to be securely expressed and enforced. One of the strengths of the technology is that the rights to use the contents of an object can be managed separately from the contents themselves. The rights to the underlying works (the original creation) can be managed separately from the rights relating to particular expressions of those works, just as they are in the real world. MusicMatch [3], developer of the MusicMatch Jukebox, the world s first personal jukebox software, is participating in Magex s unique Internet digital music pilot. The music pilot enables record labels and artists to distribute music over the Internet, protect their copyright and collect their royalty payments. The MusicMatch Jukebox software intends to integrate the Magex service into its digital audio player, allowing users to download rights protected music tracks from the Internet into the MusicMatch Jukebox. Tracks can then be organized into a digital Music Library, added to custom playlists and played back at CD-quality via the user s PC. MusicMatch intends to be a SDMI compliant product. As can be seen, the above commercial rights management systems provides certain desirable features for both consumers and service providers. These features can be the trends and directions towards the design of the future rights management systems. They are summarized as follows. In Digimarc Support a wide range of visual contents, including both image, and video media Provide a range of solutions including copyright communication, image licensing and management, and enhanced Internet commerce In InterTrust Commerce Architecture A comprehensive architecture is needed for the creation of a globally distributed Intertrustworhty TM environment The environment provides the basis for real-world rights and obligation, including intellectual property rights to be securely expressed and enforced In MusicMatch Enable record labels and artists to distribute music over the Internet, protect their copyright and collect their royalty payment Integrate the services into its digital audio player Allow users to download rights protected music track from the Internet into the MusicMatch Jukebox Organize tracks into a digital music Library, added to custom playlists and played back at CD-quality via the user s PC Be a SDMI compliant product Many of these features are vital for a successful rights management system but unfortunately the actual design and implementation of them are unlikely to disclose to the public. MusicMatch announced to adopt Secure Digital Music Initiative (SDMI) in their rights management system for the protection of digital music, because SDMI is a promising architecture by Recording Industry Association of America for music security, and it will be adopted by major worldwide recording industry and technology companies in the near future.

3 Following the promising architecture of SDMI, we may be able to design a rights management system with most of the desirable features in it. With the SDMI specification version 1.0, there is not much detail about the design of digital watermark for rights management, although digital watermarking is used for rights management in the specifications. Besides, digital watermarking can be used for other value-added applications, apart from rights management, for example, marketing. It could be an advantage of integrating such applications in the system in a competitive business world. Desirable features include a support of other digital media, but SDMI can apply to digital music only. A feasibility study is needed to address this issue. This paper intends to response to these issues and proposes an SDMI-based rights management system using digital watermarking for electronic media including audio and video data. Digital Watermarking Digital watermarking is a promising technology that can contribute to the battle against piracy in the information age. Although the development of digital watermarking is still at its infant stage, digital watermarking has already attracted many first-rate researchers. Many watermarking techniques and commercial watermarking systems have been proposed and developed to focus on rights management, especially copyright protection of digital media. Three basic watermarking procedures are required in digital watermarking and they are watermark insertion, watermark detection and watermark extraction. In general, watermark insertion requires (i) an original data, (ii) a watermark, and (iii) and a private key. The watermark can be information about ownership, user identity, description of the original data, etc. The watermark insertion procedure is to embed a watermark into the original data. The watermark can be perceptible or imperceptible in the watermarked data depending on the applications. For applications requiring the original data not being distorted, imperceptible watermark is desired. For some other applications, which require the embedded data, for example company logo or trademark to be shown, a perceptible watermark is preferred. Watermark extraction and watermark detection are used to retrieve and verify the embedded watermark from the watermarked data, respectively. For watermark extraction, a public key is used together with the watermarked data to retrieve the embedded watermark. For watermark detection, a public key and a specified ID - watermark are used together with the watermarked data to determine whether the watermark is correct. Digital watermark is the key in digital watermarking. Digital watermark is basically a series of number for digital music in practice, while it can be a pattern, a logo in visual digital content, such as video and image. However, they all have something in common; that is the watermark in these applications carrying meaning information for later processing. In the context of rights management, this information may serve for owner verification, usage control, access control, and many others. Secure Digital Music Initiative (SDMI) The objectives of Secure Digital Music Initiative (SDMI) [6] are to provide consumers for convenient access to quality recordings, ensure copyright protection for artists work, and enable technology and music companies to build successful businesses. SDMI is a forum for music industries to develop the voluntary, open architecture for playing, storing and distributing digital music necessary to enable a new market to emerge. SDMI is working on two tracks. The first has already produced a standard, or specification, for portable devices. The longer-term effort is working toward completion of an overall architecture for delivery of digital music in all forms. The SDMI is composed of a number of functional components; including Portable Device (PD), Licensed Compliant Module (LCM), and Portable Media (PM). They provide a secure environment for music distribution, rendering, and storing. The functional reference model of SDMI version 1.0 is depicted in Figure 1. Different components are operated at different layers in the reference model. Application Layer The application layer is where all SDMI-Compliant electronic music distribution applications, software players, home library software applications, CD extractors and other applications reside. In this reference model, digital rights management and screening occur in the application layer but an application may use any trusted delegate (including, but not limited to, an LCM) for any task prescribed for applications within this specification. LCM The Licensed Compliant Module (LCM) is the module that transfers content from SDMI-Compliant applications to PDs, and PMs that use one or more formats. In that case where there is a PD format that the application cannot interpret, the LCM may serve the role of a trusted translator, so that SDMI applications are not required to communicate directly with all PD formats. As depicted in Figure 1, it is anticipated that an application may communicate with multiple LCMs. A single LCM may also communicate with multiple applications. One important function of an LCM is to provide an abstracted device interface to SDMI applications for PDs/PMs. Portable Device The Portable Device (PD) layer receives only SDMI protected content from the LCM-PD interface, including transfer of content to the PD from a PM. The PD layer constitutes the playback component of the PD reference

4 model as depicted in Figure 2, which allows for multiple PD formats. Digital Watermarking in SDMI The SDMI portable device specification [6] states that digital watermarking is required for SDMI protected content for both local and distributed. Electronic music distribution (EMD) can also be watermarked. Digital watermarking is used to identify the property ownership. SDMI addresses the importance of digital watermarking, and include it in the specifications. However, the design of digital watermark for rights management and how to apply digital watermarking in an efficient way for the overall music business are not covered. In addition, other potential benefits and advantages of using digital watermarking in SDMI, such as rules usage and control functions are also not provided. One of the shortcomings of SDMI is that it can support digital music, but not other media. Rights Management in SDMI In SDMI, rights management includes usage rules that are expressed by content providers that govern the content s use in the SDMI Domain. For example, usage rules include rules governing copy (including number of copies/generations of copies permitted), move, checkin/check-out (including number of useable copies), export from the SDMI domain, and combinations thereof. Usage rules shall be embedded, attached and/or associated with its content in a protected manner. Rights Management Rights management [7], in general, refers to the problems associated with intellectual property rights, including copy protection, and in particular to the problem of assuring that, in a commerce setting, payment is made for a particular use of content, and that the use made does not exceed the use authorized. In electronic commerce setup, consumer makes transaction through the web, ordering, payment, and delivery all take place at the commerce website. It is also anticipated that the rights management should also be an online service and application. After summarizing system features of various commercial rights management products as well as features of digital watermarking, the following are some basic features that a rights management system should possess. - Enable intellectual property rights, including copy protection - Support online ownership verification - Integrate and persistently protect the artistic integrity of media - Support various electronic media and formats - Enable pass-along distribution between consumers, know who they are, and get paid by new listeners - Create merchandising, promotion, direct response marketing, and affinity groups - Receive timely financial payments and usage information for the media - Enable user s multimedia player for rights management - All media are SDMI protected content - Track the usage of the media - Locate where the media is and who owns the media - Support and respect media label policies In order to achieve system features, we propose to adopt SDMI as core architecture for the base of the rights management systems. Digital watermarking is used for the implementation of rights management, as well as for providing other value-added features to the system. Rights Management and Digital Watermarking SDMI architecture provides the basis for the wide range of real world rights and obligations, including intellectual property rights, and real-world rules related to those rights and obligations, to be securely enforced. SDMI was initially designed for digital music. However, the architecture is extendable to other electronic media, because major functional components in SDMI s architecture are addressed but not defined. It is feasible to integrate more functions in these components to support other media, while the system structure is kept as its specification. We propose an SDMI-based rights management system for various digital media using digital watermarking. The system integrates both audio and video services in it. The proposed rights management system is depicted in Figure 3. The diagram demonstrates that the RMS server is accessed by one of its client Multimedia player, although RMS server can support multi-client access. There are three major functional components in this system. They are Rights Management System (RMS) Server, Rights Management Database (RMDB), Multimedia Player (MP). Moreover, digital watermark is used to communicate with these components. Communications between two or more SDMI-compliant components are protected and authenticated by Secure Authenticated Channel (SAC) in SDMI. SDMI protected media is used throughout the system. RMS Server, RMDB, and MP In order to manage rights over distributed electronic media, it is necessary for clients to be in communication with a server. With the client/server setup, the RMS server is responsible for the global rights management, including intellectual property assets. The Global rights management means that the RMS server is in control of the overall rights management about the electronic media. The RMS server can initiate, maintain, and terminate the usage rights of the electronic media whenever the MP is accessible to the Internet. While the MP is disconnected from the Internet, the local rights management module within the MP will be invoked and will handle all rights

5 issues of the media locally under certain constraints. These constraints include the following. The MP must be registered with the RMS server before it is actually being used User must register with RMS server Authentication is enforced to the MP The local rights management must be initiated by the RMS server, when the electronic media is being loaded by the MP in the first time The usage rights for a digital media has a time limitation, so the MP is required to connect to RMS server from time to time The RMS server incorporates with the server-side database, RMDB to determine the rights for a particular electronic media. With the access request from the MP, RMS server may know the Internet Protocol address of the MP, and therefore, the RMS server may generate information about the geographical locations of the MPs, and keep them in the RMDB for further processing and other applications. Rights management database (RMDB) holds all rightsrelated information, as well as RMS server-generated information. In RMDB, a data entry may refer to customer s, company s, product s, and rights information. This can be represented by product ID, user ID, company ID, access rights, company web address, and so on. This can be a LCM from the SDMI specification. Multimedia player (MP) in the rights management system is a SDMI-compliant and video-enabled player. It is a PD and may contain LCM in it. Apart from rendering the media; video and audio, the major function of the multimedia player is to implement the rights management module within the PD. This rights management module is an additional module to manage rights locally. Design of Digital Watermark for Rights Management Digital watermarking plays an important role in rights management in SDMI, especially toward copyright protection. In the business of electronic media distribution, many business goals are needed to achieve, for instance marketing and promotion, in addition to rights management. To exercise these, information about the user (ID, credit, rights information, etc.), the user affiliation (interests, nationally, gender, etc.), the product (ID, serial no., model number, type, name, etc.), and the product affiliation (fan club, related products, accessories, etc.) are usually needed. This information can be easily related to each other using database management system, and the indexing information can be used for digital watermark in rights management. In fact, current digital watermarking technologies briefly address these issues, but this is not covered in the SDMI specification. Watermark and Rights Information Digital watermark for electronic media carries certain information that is favorable to the content providers and distributors. In rights management, authors and publishers who distribute their digital media or contents online expect to be able to specify the permitted uses of the information in a standard format. One major problem with digital contents is that it can be copied. Content providers and owners wish the rights management system can detect and track the duplicate copies. Digital watermark may contain information about the intellectual property or rights. Intellectual property information or rights information usually refers to copyright, licensing information, such as the identifier of the copyright holder, the creator of the material, authorized usage of digital media or a link (URL) through which to fetch more related information. It may also contain a serial number that uniquely identifies material to registration entities. The rights information together with product information, customer profile, and company information are represented by a key when digital watermarking is in use. The key is converted into a digital watermark using a hashing function or a random generator for data embedding. Subsequently, a host media embeds the digital watermark, and it becomes a watermarked media with right management enabling feature. Digital Watermarking for Rights Management In some cases, watermarking can also be used to identify the source of the infringing material. A company that licenses video online and enables customers to download licensed videos, can insert a separate watermark for each download with information identifying the licensee. If an unauthorized use of a video is discovered then the watermark can be checked to determine from which licensee it came. It may be that the pirate copy was copied from a legitimate publication, but it helps a rightsholder prevent unauthorized disseminated. The digital watermarking technology enables rightsholders to enforce their intellectual property rights by seeking out and prosecuting copyright pirates. As with much Internet law, there are jurisdictional problems, with infringement being rife in countries with the least protection, but the proposed harmonization provisions will at least ensure that rightsholders are able to exploit fully their works commercially in a large part of the world markets. Watermark for Marketing As copying and distributing digital assets become so easy, electronic media; e.g., audio, video, and image are moving from one place to another all the time. Some consumers like sharing digital media with others, or even with the public. Intellectual property protection becomes an important concern. Watermark contains hidden information: a product ID, user ID, the location of designated RMS server and other information. Although it is difficult to ensure a watermark is unique worldwide, careful design of the watermark, maybe with many different combinations of information can benefit to some copyright protection applications. Electronic media carrying distinct watermark can be tracked by a watermark spider through Internet, when they

6 are in use and visible to Internet programs. For example, the watermark spider, SysCoP Spider [8] acts as a robot to search for watermarked documents in the Internet and automatically locate their geographical locations. An active way to locate the electronic media is to use our MP. Whenever the MP needs to communicate with the RMS server, location of the media is automatically uploaded to the RMS server and RMDB. The rights management system can track the media, and this helps the content providers to have a focused-marketing strategy and plan for related products. A more aggressive and positive approach could be one that whenever the watermarked media are opened or reproduced, our MP will automatically forward the embedded information, including the user ID and location of the media to the RMS server. This scheme is borrowed from the SDMI architecture. This provides valuable marketing data about the distribution of products. Besides the approach may also benefit marketing campaigns and provide better management of the assets. Interfaces of Prototype We built a prototype of the SDMI-based rights management systems. Some components are completed and their interfaces are displayed in this section. There are two interfaces to show and they are RMS server administration and MP. RMS Server Administration The interface of the rights management system server administration is shown in Figure 4. As shown in the figure, the interface contains two parts. The top part is to show the status of all RMS server-side components in the system. And the bottom part gives detailed logging information about all connected RMS client multimedia players or other compatible applications. Multimedia Player The Multimedia Player is composed of three functional modules; namely Music Player, Video Player, and Minibrowser. Music Player Music Player is the default player of the MP. The interface of the music player is given in Figure 5. In the File menu, there is a Register function as shown in Figure 6. The Register: function is to invoke an online registration page to register the usage of the media to the rights management system. The registration page is also depicted in Figure 7. In the View menu as shown in Figure 8, there is a File Info option. The File Info displays the detail information of the current media file - music, such as the filename, product id, product content, product version, issued date, expiry date, access right, and so on. The Interface of the File Info page is given in Figure 9. As can be seen, the file extension is of wmm and this is the file format of our watermarked SDMI-compliant file format. Video Player Multimedia player can also support video. Figure 10 displays the interface of the video player while it is playing a video file. MiniBroswer The Multimedia player can act as a web browser. It enables users to access watermarked SDMI media efficiently via the Internet, and it also allows RMS server to communicate and update information with the MP. The interface of Minibrowser is given in Figure 11. Conclusions and Future Works This paper presented an SDMI-based rights management system. Digital watermarking is used for rights management; inserting rights information, conducting rights verification, and executing other rights-related processes. SDMI was chosen as the architecture for this rights management system because it is powered by major worldwide recording industry and technology companies. Features of the proposed system are referenced to many commercial rights management systems, in which cuttingedge technologies are used. The design of these commercial systems are varied from each other, as there is no standards or specifications to follow in designing rights management systems so far. We impose a value-added feature of digital watermarking; marketing in the system. We also discussed in details about the design of digital watermark for rights management system. The proposed system was implemented and some interfaces are included in this paper to demonstrate the functionalities of the system. The Moving Picture Experts Group (MPEG) announced in December 1999 to form a new working group towards the development of international standards on multimedia framework, which is MPEG-21. The MPEG-21 will focus on many management issues in handling multimedia data. One of them is usage rights. It is anticipated that the overall design will be similar to SDMI, but for multimedia data. The MPEG-21 document does not mention how digital watermarking relates to the standards. However, we will closely follow the development of MPEG-21 and try to adopt MPEG-21 standards in the design of our rights management system. Acknowledgement This research is supported in part by Industrial Support Fund of Hong Kong, and the Hong Kong Research Grants Council through a Direct Allocation Grant (DAG99/00.BM38) and Industrial Support Fund ( ).

7 References [1] J. Cox, J Killian, F. T. Leighton, and T. Shamoon, 1997 Secure Spread Spectrum Watermarking for Multimedia, IEEE Transactions on Image Processing, Vol. 6, No. 12, pp [2] Digimarc, [3] InterTrust, l. [4] INTERTRUST: InterTrust announces PowerChord digital rights management software, M2 Presswire, Coventry, Jun 16, [5] Page, T Rights Management: Digital Watermarking as a Form of Copyright Protection, Computer Law & Security Report, Vol. 14, No. 6, pp [6] SDMI, (SDMI Portable Device Specification - Part 1, Version 1.0 (PDWG )). [7] Stewart, T Designing Systems for Internet Commerce, Addison Wesley, pp [8] SysCoP, [9] MA Wright 1999 An overview of PKI, Network Security, pp Figure 2: Functional Reference Model of Portable Device (Version 1.0). Watermarked Media Watermark Digital Media The General System Flow of the Rights Management System Media Player at the User side SSL Internet SSL Rights Management Database (RMD) Rights Management Server (RMS) Figure 3: Components of Rights Management System using Digital Watermarking. Figure 1: Reference Model Functional Layers of SDMI (Version 1.0). Figure 4: Administration Interface of the RMS server.

8 Figure 5: Multimedia Player Interface of Music Player. Figure 9: Multimedia Player View - File Info page. Figure 6: Music Player File Menu. Figure 10: Interface of Multimedia Player - Video Player. Figure 7: Multimedia Player Registration Page. Figure 8: Interface of Multimedia Player View File Info. Figure 11: Interface of Multimedia Player - Minibrowser.