WO 98/02864
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`,
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`PCT/US97/11455-
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`OPTIMIZATION METHODSFORTHE INSERTION, PROTECTION
`AND DETECTION OF DIGITAL WATERMARKSIN DIGITIZED DATA
`
`
`RELATED APPLICATIONS
`
`This application is related to patent applications entitled
`“Steganographic Method and Device”, Serial No. 08/489, 172 filed on June
`7, 1995; “Method for Human-Assisted Random Key Generation and
`Application for Digital Watermark System’, Serial No. 08/587,944 filed on
`January 17, 1996; “Method for Stega-Cipher Protection of Computer Code”,
`Serial No. 08/587943 filed on January 17, 1996; “Digital Information
`
`Commodities Exchange”, Serial No. 08/365,454 filed on December28,
`
`1994, which is a continuation of Serial No. 08/083,593 filed on June 30,
`1993; and “Exchange Mechanismsfor Digital Information Packages with |
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`Bandwidth Securitization, Multichannel Digital Watermarks, and Key
`
`. Management’, Serial No. 08/674,726filed on July 2, 1996. These related
`applications are all incorporated herein by reference.
`This application is also related to U.S. Patent No. 5,428,606,
`“Digital Information Commodities Exchange”, issued on June 27, 1995,
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`which is incorporated herein by reference.
`
`
`BACKGROUNDOF THE INVENTION
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`The presentinvention relates to digital watermarks.
`Digital watermarks exist at a convergence point where creators and
`publishers ofdigitized multimedia content demand localized, secured
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`identification and authentication of that content. Because existence of
`piracy is clearly a disincentive to the digital distribution of copyrighted
`works, establishment of responsibility for copies and derivative copies of
`such worksis invaluable.
`In considering the various forms of multimedia
`content, whether "master," stereo, NTSC video, audio tape or compactdisc,
`_ tolerance of quality degradation will vary with individuals and affect the
`underlying commercial and aesthetic value of the content.
`it is desirable to
`
`tie copyrights, ownership rights, purchaser information or some combination
`
`of these and related data to the content in such a mannerthat the content
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`must undergo damage,and therefore a reduction in value, with subsequent,
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`unauthorized distribution of the content, whetherit be commercial or
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`otherwise.
`Legal recognition and attitude shifts, which recognize the importance
`__ Of digital watermarks as a necessary component of commercially distributed
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`content (audio, video, game, etc.}, will further the development of
`acceptable parameters for the exchange of such content by the various
`parties engagedin the commercial distribution of digital content. These
`parties mayinclude artists, engineers, studios, INTERNET access
`providers, publishers, agents, on-line service providers, aggregators of
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`contentfor various forms of delivery, on-line retailers, individuals and
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`parties that participate in the transfer of funds to arbitrate the actual delivery
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`of content to intended parties.
`Since the characteristics of digital recordings vary widely,it is a
`
`worthwhile goal to provide tools to describe an optimized envelope of
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`parameters for inserting, protecting and detecting digital watermarks in a
`given digitized sample (audio, video,virtual reality, etc.) stream. The
`optimization techniques described hereinafter make unauthorized removal
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`of digital watermarks containing these parameters a significantly costly
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`operation in terms of the absolute given projected economic gain from
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`undetected commercial distribution. The optimization techniques, at the
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`least, require significant damage to the content signal, as to make the
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`“
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`unauthorized copy commercially worthless,if the digital watermarkis
`removed, absent the use of extremely expensive tools.
`_
`Presumably, the commercial value of some workswill dictate some
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`level of piracy not detectable in practice and deemed “reasonable”byrights
`holders given the overall economic return: For example, there will always
`be fake $100bills, LEVI jeans, and GUCCI bags, given the sizes of the
`overall markets and potential economic returns for pirates in these markets--
`as there also will be unauthorized copies of works of music, operating
`systems (Windows95,etc.), video and future multimedia goods.
`However, whatdifferentiates the "digital marketplace" from the
`physical marketplaceis the absence of any schemethat establishes
`responsibility and trust in the authenticity of goods. For physical products,
`corporations and governments mark the goods and monitor manufacturing
`
`capacity and sales to estimate loss from piracy. There also exist reinforcing
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`mechanisms,including jegal, electronic, and informational campaignsto
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`better educate consumers.
`
`SUMMARYOF THE INVENTION
`
`The present invention relates to implementations of digitai
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`watermarksthat are optimally suited to particular transmission, distribution
`
`and storage mediumsgiven the nature of digitally-sampled audio, video,
`
`and other multimedia works.
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`The present invention also relates to adapting watermark application
`parametersto the individual characteristics of a given digital sample stream.
`The present invention additionally relates to the implementation of
`
`digital watermarks that are feature-based. That is, a system where
`
`watermark information is not carried in individual samples, but is carried in
`
`the relationships between multiple samples, such as in a waveform shape.
`
`The present invention envisions natural extensions for digital watermarks
`
`that may also separate frequencies (color or audio), channels in 3D while
`utilizing discretenessin feature-based encoding only known to those with
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`pseudo-random keys(i.e., cryptographic keys) or possibly tools to access
`such information, which may one day exist on a quantum level.
`The present invention additionally relates to a method for obtaining
`
`;
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`more optimal models to design watermark systemsthat are tamper-resistant
`
`given the number and breadth of existent digitized-sample options with
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`differing frequency and time components (audio, video, pictures, multimedia,
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`virtual reality, etc.).
`To accomplish thesegoals, the present invention maintains the
`highest quality of a given content signal as it was mastered, withits
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`watermarks suitably hidden, taking into account usageofdigitalfilters and
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`error correction presently concerned solely with the quality of content
`
`signais.
`
`The present invention additionally preserves quality of underlying
`content signals, while using methods for quantifying this quality to identify
`and highlight advantageous locations for the insertion of digital watermarks.
`
`The present invention integrates the watermark, an information
`
`signal, as closely as possible to the content signal, at a maximal level, to
`
`force degradation of the content signal when attempts are made to remove
`
`the watermarks.
`The present invention relates to a method for amplitude independent
`encoding of digital watermark information in a signal including steps of
`.
`determining in the signal a sample window having a minimum and a
`maximum, determining a quantization interval of the sample window,
`normalizing the sample window, normalizing the sample window to provide
`normalized samples, analyzing the normalized samples, comparing the
`normalized samples to messagebits, adjustingthe quantization level of the
`sample window to correspond to the messagebit when a bit conflicts with
`the quantization level and de-normalizing the analyzed samples.
`The present invention also relates to a method for amplitude
`independent decoding of digital watermark informationin a signal including
`steps of determining in the signal a sample window having a minimum and a
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`maximum, determining a quantization interval of the sample window,
`normalizing the sample window to provide samples, and analyzing the
`quantization level of the samples to determine a messagebit value.
`The present invention additionally relates to a method of encoding
`and decoding watermarksin a signal where, rather than individual! samples,
`insertion and detection of abstract signal features to carry watermark
`
`information in the signal is done.
`The present invention also relates to a method for pre-analyzing a
`digital signal for encoding digital watermarks using an optimaldigitalfilter in
`whichit is determined what noise elements in the digital signal will be
`removed by the optimaldigital filter based on response characteristics of the
`
`filter.
`
`The present invention also relates to a method of error coding
`watermark messagecertificates using cross-interleaved codes which use
`error codes of high redundancy,including codes with Hamming distancesof
`greater than or equalto “n’, wherein “n’” is a numberof bits in a message
`block.
`
`The present invention additionally relates to a method of pre-
`processing a watermark messagecertificate including a step of determining
`anabsolute bit length of the watermark messageasit will be encoded.
`The present invention additionally relates to a method of generating
`watermark pseudo-random key bits using a non-linear (chaotic) generator or
`_ toa method of mapping pseudo-random key and processing state
`
`information to affect an encode/decode map using a non-linear (chaotic)
`
`generator.
`The present invention additionally relates to a method of
`guaranteeing watermark certificate uniquenessincluding a step of attaching
`atime stamporuseridentification dependent hash or message digest of
`
`watermark certificate data to the certificate.
`
`The present invention also relates to a method of generating and
`quantizing a local noise signal to contain watermark information where the
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`noise signalis a function of at least one variable which depends on key and
`
`processing state information.
`The presentinvention also relates to a method of dithering watermark
`quantizations such that the dither changes an absolute quantization value,
`but does not change a quantization level or information carried in the
`
`quantization.
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`The present invention further relates to a method of encoding
`
`watermarksincluding inverting at least one watermark bit stream and
`encoding a watermark including the inverted watermark bit stream.
`The present invention also relates to a method of decoding
`watermarks by considering an original watermark synchronization marker,
`an inverted watermark synchronization marker, and inverted watermarks,
`
`and decoding based on those considerations.
`The present invention also relates to a method of encoding and
`decoding watermarksin a signal using a spread spectrum technique to
`
`encode or decode whereinformation is encoded or decoded at audible
`
`levels and randomized over both frequency and time.
`
`The present invention additionally relates to a method of analyzing
`
`composite digitized signals for watermarks including obtaining a composite
`signal, obtaining an unwatermarked sample signal, time aligning the
`unwatermarked sample signal to the composite signal, gain adjusting the
`
`time aligned unwatermarked sample signal!to the composite signal,
`
`estimating a pre-composite signal using the composite signal and the gain
`
`adjusted unwatermarked sample signa!, estimating a watermarked sample
`signal by subtracting the estimated pre-composite signal for the composite.
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`signal, and scanning the estimated watermark sample signalfor
`watermarks.
`The present invention additionally relates to a method for varying
`watermark encode/decode algorithms automatically during the encoding or
`decoding of a watermark including steps of (a) assigning a list of desired
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`CODECsto a list of corresponding signal characteristics which indicate use
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`of particular CODECs,(b) during encoding/decoding, analyzing
`characteristics of the current sample framein the signal stream, prior to
`delivering the frame to CODEC, (c) looking up the corresponding CODEC
`from the list of CODECs in step (a) which matches the observed signal
`
`characteristics from step (b), (d) loading and/or preparing the desired
`CODEC,(e) passing the sample frame to the CODECselectedin step(c),
`andf) receiving the output samples from step (e).
`
`The present invention also relates to a method for varying watermark
`encode/decodealgorithms automatically during the encoding or decoding of
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`15.
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`a watermark, including steps of (a) assigninga list of desired CODECs toa
`list of index values which correspond to values computed to values
`computed asa function of the pseudo-random watermark key and the state
`of the processing framework, (b) during encoding/decoding, computing the
`. pseudo-random key index value for the current sample frame in the signal
`stream, prior to delivering the frame to a CODEC, (c) looking up the
`corresponding CODECfrom thelist of CODECsin step (a) which matches
`the index value from step (b), (d) loading and/or preparing the desired
`
`CODEC, (e) passing the sample frame to the CODECselectedin step (c),
`
`and(f) receiving the output samples from step (e).
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`
`DETAILED DESCRIPTION
`
`The present invention relates to implementations of digital
`
`watermarksthat are optimally suited to particular transmission, distribution
`
`and storage mediums given the nature ofdigitally sampled audio, video, and
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`other multimedia works.
`
`The present invention also relates to adapting watermark application
`parameters to the individual characteristics of a given digital sample stream.
`The present invention additionaliy relates to the implementation of
`digital watermarks that are feature-based. That is, a system where
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`watermark information is not carried in individual samples, but is carried in
`
`the relationships between multiple samples, such as in a waveform shape.
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`For example,in the same manner a US $100bill has copy protection
`features including ink type, paper stock,fiber, angles of artwork that distort
`in photocopier machines, inserted magnetic strips, and composite art, the
`presentinvention envisions natural extensions for digital watermarksthat
`may also separate frequencies (color or audio), channels in 3D while
`utilizing discreteness in feature-based encoding only known to those with
`pseudo-random keys(i.e., cryptographic keys) or possibly tools to access
`such information, which may one day exist on a quantum level.
`There are a number of hardware and software approachesin the
`prior art that attempt to provide protection of multimedia content, including
`encryption, cryptographic containers, cryptographic envelopes or
`|
`"eryptolopes", and trusted systems in general. None of these systems
`places control of copy protection in the hands of the content creator as the
`
`content is created, nor provides an economically feasible modelfor-
`exchanging the content to be exchangedwith identification data embedded
`within the content.
`
`Yet, given the existence of over 100 million personal computers and
`many more non-copy-protected consumer electronic goods, copy protection
`seemsto belong within the signals. Afterall, the playing (i.e., using) of the
`content establishes its commercial value.
`
`Generally, encryption and cryptographic containers serve copyright
`holders as a meansto protect data in transit between a publisher or
`distributor and the purchaserof the data (i.e., a meansof securing the
`delivery of copyrighted material from one location to another by using
`variations of public key cryptography or other more centralized
`cryptosystems).
`—
`Cryptolopes are suited specifically for copyrighted text that is time-
`sensitive, such as newspapers, whereintellectual property rights and origin
`data are made a permanentpart of the file. For information on public-key
`cryptosystems see U.S. Patent No. 4,200,770 to Hellmanet al., U.S. Patent
`No. 4,218,582 to Hellman et al., U.S. Patent No. 4,405,829to Rivestetal., -
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`and U.S. Patent No. 4,424,414 to Hellman et al. Systems are proposed by
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`IBM and Electronic Publishing Resources to accomplish cryptographic
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`container security.
`Digitally-sampled copyrighted material, that is binary data on a
`fundamentallevel, is a special case becauseofits long term value coupled
`
`with the ease and perfectness of copying and transmission by general
`
`purpose computing and telecommunications devices.
`
`In particular,in
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`digitally-sampled material, there is no loss of quality in copies and no
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`identifiable differences between one copy and any other subsequent copy.
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`For creators of content, distribution costs may be minimized with electronic
`
`transmission of copyrighted works. Unfortunately, seeking some form of
`
`informational or commercial return via electronic exchangeisill-advised
`absentthe use of digital watermarksto establish responsibility for specific
`copies and unauthorized copying. Absentdigital watermarks, the unlikely
`instance of a market of trusted parties who report any distribution or
`exchange of unauthorized copiesof the protected work must be relied upon
`for enforcement. Simply, content creators still cannot independently verify
`
`watermarks should they choose to do so.
`
`For a discussion of systems that are oriented around content-based
`
`addresses and directories, see U.S. Patent No. 5,428,606 to Moskowitz.
`In combining steganographic methodsfor insertion of information
`identifying the title, copyright holder, pricing, distribution path, licensed
`owner of a particular copy, or a myriad of other related information, with
`pseudo-random keys (which mapinsertion location of the information)
`similar to those usedin cryptographic applications, randomly placed signals
`(digital watermarks) can be encoded as random noise in a content signal.
`
`Optimal planning of digital watermark insertion can be based on the
`inversion of optimaldigitalfilters to establish or map areascomprising a
`given content signal insertion envelope. Taken further, planning operations
`will vary for different digitized content: audio, video, multimedia, virtual
`reality, etc. Optimization techniques for processes are described in the
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`Device" and “Methodfor Human Assisted Random Ke
`Application for Digital Watermark System".
`OptimizationProcessesmusttakeinto consideration thegeneralari
`| ofdigitization SystemswhereSampling andquantizing arefundamental
`physical Parameters. Forinstance, discretetime Sampling has anatural
`limit ifpackets oftimeareused, estimated at 1x10-2Second. Thisprovides
`@ Naturallimit to the Sampling operation. Also, since noise is Preferable to
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`quantization error, burst error, andthe like is done forthe Singulargoal of
`Preserving quality in a Given digitized Sample. Theoretical perfect error
`correction is not efficient, given the requirement ofa hugeallocation of 2"bs
`redundant data to detect and Correct errors.
`In the absence of such
`7
`Overhead,all error correction is still based on data redundancy and requires
`the following operations: error detection to check data validity, error
`- correction to replace erroneous data, and error concealmentto hide large
`errors or substitute data for insufficient data correction. Even with perfect
`fror correction, the goalof a workable digital watermark system for the
`Protection of copyrights would beto distributecopiesthatare lessthan-
`perfect but.aate erceivably-cift
`enlteomthe-criginal. . tronivally,inthie’ *B,
`
`
`presentdistribution ofmultimedia,this is the approach taken by content... _ _
`creators when faced with such distribution mechanismsas the INTERNET.
`As an example,for audio clips commercially exchanged on the World Wide
`Web (WWW), a part of the INTERNET,8 bit sampled audio or audio
`—
`downsampledfrom 44.1 kHz (CD-quality), to 22 kHz and lower. Digital
`filters, however, are not ideal because oftrade-offs between attenuation and
`time-domain response, but provide the engineer or similarly-trained
`individualwith a set of decisions to make about maximizing content quality
`with minimum data overhead and consideration of the ultimate delivery
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`mechanism for the content (CDs, cable television, satellite, audio tape,
`stereo amplifier, etc.).
`|
`For audio signals and more generally for other frequency-based
`content, such as video, one method of usingdigitalfilters is to include the
`use of an inputfilter to prevent frequency aliasing higher than the so-called
`
`Nyquist frequencies. The Nyquist theorem specifies that the sampling
`
`frequency must be at least twice the highest signal frequency of the
`
`sampled information (e.g., for the case of audio, human perception of audio
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`frequenciesis in a range between 20 Hz and 20 kHz). Without an input
`filter, aliases can still occur leaving an aliased signal in the original
`bandwidth that cannot be removed.
`
`Even with anti-aliasing filters, quantization error can still cause low
`level aliasing which may be removedwith a dither technique. Dither is a
`
`method of adding random noise to the signal, and is used to de-correlate
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`quantization error from the signal while reducing the audibility of the
`
`remaining noise. Distortion may be removed, but at the cost of adding more
`noise to thefiltered output signal. An important effect is the subsequent
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`randomization of the quantization error while still leaving an envelope of an
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`unremovable signaling band of noise. Thus, dither is done at low signal
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`levels, effecting only the least significant bits of the samples. Conversely,
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`digital watermarks, which are essentially randomly-mappednoise, are
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`intended to be inserted into samplesof digitized content in a manner such
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`as to maximize encoding levels while minimizing any perceivable artifacts
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`that would indicate their presence or allow for removalbyfilters, and without
`destroying the content signal. Further, digital watermarks should be
`~
`inserted with processes that necessitate random searching in the content
`signal for watermarksif an attacker lacks the keys. Attempts to over-encode
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`_
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`noise into known watermarked signal locations to eliminate the information
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`signal can be madedifficult or impossible without damaging the content
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`signal by relying on temporal encoding and randomization in the generation
`of keys during digital watermark insertion. As a result, although the
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`_watermark occupies only a small percentageof the signal, an attackeris
`forced to over-encode the entire signal at the highest encoding level, which
`creates audible artifacts.
`
`The present invention relates to methods for obtaining more optimal
`models to design watermark systemsthat are tamper-resistant given the
`number and breadth of existent digitized sample options with differing
`frequency and time components (audio, video, pictures, multimedia, virtual
`reality, etc.).
`To accomplish these goals, the present invention maintains the
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`highest quality of a given content signal as it was mastered, with its
`
`watermarkssuitably hidden, taking into account usageofdigitalfilters and
`error correction presently concerned solely with the quality of content
`signals.
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`Additionally, where a watermark location is determined in a random
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`or pseudo-random operation dependent on the creation of a pseudo-random
`key, as described in copendingrelated application entitled "Steganographic
`Method and Device" assigned to the present assignee, and unlike other
`forms of manipulating digitized sample streams to improve quality or encode
`known frequency ranges, an engineer seeking to provide high levels of
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`protection of copyrights, ownership, etc. is concerned with the size of a
`
`given key, the size of the watermark message and the mostsuitable area
`
`and method of insertion. Robustness is improved through highly redundant
`error correction codes andinterleaving, including codes known generally as
`q-ary Bose-Chaudhuri-Hocquenghem (BCH) codes, a subset of Hamming
`coding operations, and codes combining error correction and interleaving,
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`such as the Cross-Interleave Reed-Solomon Code. Using such codesto
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`store watermark information in the signal increases the numberof changes
`
`required to obliterate a given watermark. Preprocessing the certificate by
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`considering error correction and the introduction of random data to make
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`watermark discovery moredifficult, prior to watermarking, will heip
`determine sufficient key size. More generally, absolute key size can be
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`. determined through preprocessing the message and the actualdigital
`watermark (a file including information regarding the copyright owner,
`
`publisher, or some other party in the chain of exchange of the content) to
`
`compute the absolute encodedbit stream andlimiting or adjusting the key
`size parameter to optimize the usage of key bits. The numberof bits in the
`primary key should match or exceed the numberof bits in the watermark
`message,to prevent redundant usageof key bits. Optimally, the number of
`bits in the primary key should exactly match the watermark size, since any
`
`extra bits are wasted computation.
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`insertion of informational signals into content signals and ranges from
`applications that originate in spread spectrum techniques have been
`contemplated. More detailed discussions are included in copending related
`applications entitled "Steganographic Method and Device"and entitled
`“Method for Human Assisted Random Key Generation and Application for
`Digital Watermark System".
`.
`The following discussionillustrates some previously disclosed
`systems and their weaknesses.
`
`Typically, previously disclosed systems lack emphasis or
`
`implementation of any pseudo-random operations to determine the insertion
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`location, or map, of information signals relating to the watermarks. Instead,
`
`previous implementations provide “copy protect" flags in obvious, apparent
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`and easily removable locations. Further, previous implementations do not
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`emphasize the alteration of the content signal upon removal of the copy
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`protection.
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`Standardsfor digital audio tape (DAT) prescribe insertion of data
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`such as ISRC (Industry Standard Recording Codes)codes,title, and time in
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`sub-code according to the Serial Copy Management System (SCMS)to
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`prevent multiple copying of the content. One time copying is permitted,
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`30
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`however, and systems with AES3 connectors, which essentially override
`copy protection in the sub-code as implemented by SCMS,actually have no
`copylimitations. The present invention provides improvement overthis
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`DISH-Blue Spike-602
`Exhibit 1006, Page 0743
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`WO 98/02864
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`PCT/US97/11455
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`implementation with regard to the ability of unscrupulous users to load
`digital data into unprotected systems, such general computing devices,that
`may store the audio clip in a generalizedfile format to be distributed over an
`on-line system for further duplication. The security of SCMS (Serial Copy
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`Management System) can only exist as far as the support of similarly-
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`oriented hardware and the lack of attempts by those skilled in the art to
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`simply remove the subcode data in question.
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`Previous methods seek to protect content, but shortcomings are
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`apparent. U.S. Patent No. 5,319,735 to Preuss et al. discusses a spread
`spectrum method that would allow for over-encoding of the described, thus
`known, frequency range and is severely limited in the amount of data that
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`can be encoded-- 4.3 8-bit symbols per second. However, with the Preuss
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`et al. method, randomization attacks will not result in audible artifacts in the
`carrier signal, or degradation of the content as the information signalis in
`the subaudible range.
`It is important to note the difference in application
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`between spread spectrum in military field use for protection of real-time ©
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`radio signals, and encoding information into static audio files.
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`In the
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`protection of real-time communications, spread spectrum has anti-jam _
`features, since information is sent over several channelsat once.
`Therefore, in order to jam the signal, one has to jam all channels, including
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`their own.
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`In a static audio file, however, an attacker has practically
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`unlimited time and processing power to randomize each sub-channel in the
`signaling band without penalty to themselves, so the anti-jam advantagesof
`spread spectrum do not extend to this domain.
`In a completely different implementation, U.S. Patent No. 5,379,345
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`to Greenberg seeks enforcementof broadcast contracts using a spread
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`spectrum modulatorto insert signals that are then confirmed by a spread
`spectrum-capable receiver to establish the timing and length that a given,
`marked advertisement is played. This information is measured against a
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`specific master of the underlying broadcast material. The Greenberg patent
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`does not ensure that real-time downloads of copyrighted content can be
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`Exhibit 1006, Page 0744
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`DISH-Blue Spike-602
`Exhibit 1006, Page 0744
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`WO98/02864
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`PCT/US97/11455
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`marked with identification information unless all download accesspoints
`(PCs, modems,etc.}, and upload points for that matter, have spread
`spectrum devices for monitoring.
`Other methodsinclude techniques similar to those disclosed in
`related copending patent applications mentioned above by the present
`assignee, but lack the pseudo-random dimension of those patent
`applications for securing the location of the signals inserted into the content.
`One implementation conducted by Michae! Gerzon and Peter Craven, and
`described by Ken Pohimannin the 3rd edition of Principles of Digital Audio,
`illustrates a technology called "buried data technique,” but does not address
`the importance of randomnessin establishing the insertion locations of the
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`informational signals in a given content signal, as no pseudo-random
`methodsare used as a basis forinsertion. The overriding concern of the
`"buried data techniques" appears to be to provide for a "known channel" to
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`be inserted in such a mannerasto leavelittle or no perceivable artifacts in
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`the content signal while prescribing the exact location of the information
`(i.e., replacing the least significant bits (LSB) in a given information signal).
`In Gerzon and Craven's example, a 20-bit signal gives way to 4-bits of LSBs
`for adding about 27 dB of noise to the music. Per channel data insertion
`reached 176.4 kilobits per second per channel, or 352.8 kbps with stereo
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`channels. Similarly attempted data insertion by the present inventors using
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`random data insertion yielded similar rates. The described techniques may
`be invaluable to manufacturers seeking to support improvements in audio,
`video and multimedia quality improvements. These include multiple audio
`channel support, surround sound, compressedinformation on dynamic
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`range, or any combination of these and similar data to improve quality.
`Unfortunately, this doeslittle or nothing to protect the interests of copyright
`holders from unscrupulouspirates, as they attempt to create unmarked,
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`perfect copies of copyrighted works.
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`The present invention also relates to copending patent applications
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`is
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`DISH-Blue Spike-602
`Exhibit 1006, Page 0745
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`DISH-Blue Spike-602
`Exhibit 1006, Page 0745
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`WO 98/02864
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`PCT/US97/11455
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`entitled “Staganographicc Method and Device”; “Method for Human-
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`Assisted Random Key Generation and Application for Digital Watermark
`System’. and “Method for Stega-Cipher Protection of Computer Code” as
`mentioned above, specifically addressing the weaknessof inserting
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`informational signals or digital watermarks