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Digitalwatermarking

Jan 21, 2015

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  • 1. 1DIGITAL WATERMARKINGVISVESVARAYA TECHNOLOGICAL UNIVERSITY JnanaSangama, Machche, Belgaum 590 014A seminar report on DIGITAL WATERMARKING Submitted byMOHAMMED JASHIM 1NH08EC034VIII SEMESTER, Section A Department of Electronics & Communication EngineeringNEW HORIZONCOLLEGE OF ENGINEERING(Accredited by NBA, Permanently affiliated to VTU) Outer Ring Road, Bellandur Post, Near Marathalli, Bengaluru 560 1032011 12Department of Electronics & Communication, NHCE2011-12

2. 2DIGITAL WATERMARKINGNEW HORIZON COLLEGE OF ENGINEERING Outer Ring Road, Bellandur Post, Near Marathalli,Bengaluru 560 103 DEPARTMENT OF ELECTRONICS AND COMMUNICATION CertificateThis is to certify that the seminar entitled DIGITAL WATERMARKINGis a bonafidework carried out by Mr.MOHAMMED JASHIMbearing the USN1NH08EC034, in partialfulfillment for the award of the degree of Bachelor of Engineering in Electronics &Communicationof the Visvesvaraya Technological University, Belgaum during theacademic year 2011 - 12. This seminar report has been approved as it satisfies the academicrequirements in respect of the Seminar Work (bearing the subject code 06EC86, for the VIIIsemester during February-June 2012) prescribed for the Bachelor of Engineering Degree... ..Signature of the Coordinator Signature of the HODMr. Aravinda K. Dr. T.N. BasavarajAssistant Professor,Professor,Dept. of E&C, NHCE, Dept. of E&C, NHCE,Bengaluru 560 103 Bengaluru 560 103Department of Electronics & Communication, NHCE2011-12 3. 3DIGITAL WATERMARKING ABSTRACT As more and more analogue systems are replaced by digital ones, the question of howto deal with piracy of copyrighted digital content is turning into a serious problem. Forexample, the speed with which the Content Scrambling System the encryption standardused for DVD video was broken, clearly shows, that encryption on its own is insufficientfor many systems in protecting copyrighted material from misuse. Digital Watermarking, onthe other hand, relies on the shortcomings of the human visual system (HVS) and is aboutembedding copyright information in a way that it is imperceivable by humans, while stillbeing resistant to modifications of the cover media. Thus, digital watermarking can beconsidered to be a supplementary technique to well established encryption schemes. (i)Department of Electronics & Communication, NHCE 2011-12 4. 4DIGITAL WATERMARKING ACKNOWLEDGMENTI express my sincere thanks to Prof.Dr. T.N. Basavaraj(HOD E&C, NHCE).Mr. AravindaK(Assistant Professor,E&C,NHCE) for their kind co-operation for presentingthe seminar. I also extend my sincere thanks to all other members of the faculty of Electronics and Communication Department and my friends for their co-operation and encouragement.(ii)Department of Electronics & Communication, NHCE 2011-12 5. 5DIGITAL WATERMARKING TABLE OF CONTENTSSI noDESCRIPTIONPAGE NO : 1INTRODUCTION6 2DIGITAL WATERMARKING TECHNOLOGY10OVERVIEW 3 CLASSIFICATION11 4DIGITAL WATERMARKING TECHNICAL 14DETAILS 5WATERMARKING AS COMMUNICATION17 6DIGITAL WATERMARKING METHODS 19 7 DISTORTION AND ATTACKS23 8APPLICATION OF DIGITAL WATERMARKING25 9 CONCLUSION2910 REFERENCES30Department of Electronics & Communication, NHCE 2011-12 6. 6DIGITAL WATERMARKINGCHAPTER 1 INTRODUCTIONAlong with the explosive growth of the Internet not only desirable new possibilities -like publicly available access to information databases around the world, distributedproject work across different countries, or fast and reliable means of electroniccommunication - emerged, but the ease with which digital media can be duplicated andmodified, or the fact that legislation is seemingly unable to cope with its rapid rate ofchange makes it also very attractive to people with dishonourable motives. The adventof the Internet has resulted in many new opportunities for the creation and delivery ofcontent in digital form. Applications include electronic advertising, realtime video andaudio delivery, digital repositories and libraries, and Web publishing. An importantissue that arises in these applications is the protection of the rights of all participants. Ithas been recognized for quite some time that current copyright laws are inadequate fordealing with digital data. This has led to an interest towards developing new copydeterrence and protection mechanisms. One such effort that has been attractingincreasing interest is based on digital watermarking techniques. Digital watermarking isthe process of embedding information into digital multimedia content such that theinformation (which we call the watermark) can later be extracted or detected for avariety of purposes including copy prevention and control. Digital watermarking hasbecome an active and important area of research, and development andcommercialization of watermarking techniques is being deemed essential to helpaddress some of the challenges faced by the rapid proliferation of digital content.With these drawbacks of the digital age in mind, creators of multimedia content may wishfor a digital analogy to the watermarks that have been used in bookmaking since the 13thCentury .This need for methods and tools to protect ones intellectual property rights initiatedthe relatively new research field of digital watermarks. Someone familiar with encryptiontechniques might be tempted to ask why there is such an amount of interest in the researchcommunity to develop robust watermarking techniques, if numerous secure encryptionalgorithms are readily available. There are several reasons for this: 1.Encryption alone often is insufficient to protect digital content, sinceunconsidered and erroneoususage by human operators often renders it useless. 2. If somebody breaks the encryption (e.g. breaking the content scrambling systemused on DVDswith tools like DeCSS, VobDec or SmartRipper), copyrightinfringements can still be provenusing the embedded watermark.Department of Electronics & Communication, NHCE2011-12 7. 7DIGITAL WATERMARKING 3. The decryption process usually depends on the data being unmodified. 4. Since rightful owners are to be allowed to access the data they paid for, the encryption needs tobe undone at some point. As the unencrypted data is normally being held in the main memory ofcomputers, its not too difficult to devise tools for storing it onto a local hard disk (e.g. many DVDplayers for the Windows OS use DirectShow for video output. This proves to be useful for multiangleDVDs, where applications like DeCSS fail. By using tools that implement appropriate DirectShowfilters to write the decoded images to a user-specified file instead of displaying them onthe screen (e.g. DVDRip), the raw video data is still accessible. Because of these shortcomings, digital watermarking is sometimes referred to as being the last lineof defence. Consequently, an effective watermark should normally have several properties, whoseimportance will vary depending upon the application.Robustnesso Fragile Watermarks are highly sensitive to any modifications, theirsole purpose beingto prove the authenticity of a document. o Robust Watermarks should be embedded in a way, that they cannot be removedfrom the data without introducing noticeable defects.PerceptibilityoVisible Watermarks are added as a perceivable additional layer to theoriginal dataoInvisible Watermarks should not be perceivable by human senses. Security Unauthorized parties should not be able to read or alter the watermark, even if theyhave detailed knowledge about the used algorithms (Kerckhoffss maxim).Multiple Watermarks Does the watermarking algorithm allow for multiplewatermarks to be detectedindependently of each other?Speed In video distribution systems it may be necessary to use asymmetricalgorithms, which offer very fast embedding methods, whereas watermark detection can take arbitrarily longer. Digital watermarking is still a very young research area, with its first academic conferenceheld in 1996 [Ande99]. Numerous algorithms have been proposed and dismissed since then.Therefore, this paper aims at describing one popular watermarking technique in detail(Spread Spectrum Watermarking), rather than providing a short and unsatisfactoryexplanation of a larger number of different methods.Department of Electronics & Communication, NHCE 2011-12 8. 8DIGITAL WATERMARKING INFORMATION HIDING: Steganography & DigitalWatermarkingIn addition to digital watermarking, the general idea of hiding some information in digitalcontent has a wider class of applications that go beyond mere copyright protection andauthentication.The techniques involved in such applications are collectively referred to as informationhiding. It contains a large range of problem beyond that of embedding message incontent,keeping the existence of information secret and imperceptible.For example, an image printed on a document could be annotated by information that couldlead an user to its high resolution version STEGANOGRAPHY:Another topic that is related to watermarking is steganography. Steganography applicationsconceal information in other, seemingly innocent media. Steganographic results maymasquerade as other file for data types, be concealed within various media, or even hidden innetwork traffic or disk space. We are only limited by our imagination in the many waysinformation and data can be exploited to conceal additional information. Althoughsteganography has been studied as part of cryptography for many decades, the focus ofsteganography is secret communication. In fact, the modern formulation of the problem goesby the name of the prisoners problem.Here Alice and Bob are trying to hatch an escape planwhile in prison. The problem is that all communication between them is examined by awarden, Wendy, who will place both of them in solitary confinement at the first hint of anysuspicious communication. Hence, Alice and Bob must trade seemingly inconspicuousmessages that actually con