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In:Proc.of1995IEEEWorkshoponNonlinearSignalandImageProcessing(NeosMarmaras,Greece,June20-22,1995)1TowardsRobustandHiddenImageCopyrightLabelingE.Koch&J.ZhaoFraunhoferInstituteforComputerGraphicsWilhelminenstr.7,64283Darmstadt,Germanyemail:{ekoch,zhao}@igd.fhg.deAbstract––Thispaperfirstpresentsa”hiddenlabel”approachforidentifyingtheownershipanddistributionofmultimediainformation(imageorvideodata)indigitalnetworkedenvironment.Thenitdiscussescriteriaanddifficultiesinimplementingtheapproach.FinallyamethodusingaJPEGmodelbased,frequencyhopped,randomlysequencedpulsepositionmodulatedcode(RSPPMC)isdescribed.Thismethodsupportsrobustnessofembeddedlabelsagainstseveraldamagingpossibilitiessuchaslossydatacompression,lowpassfilteringand/orcolorspaceconversion.1IntroductionTheelectronicrepresentationandtransferofdigitizedmultimediainformation(text,video,andaudio)haveincreasedthepotentialformisuseandtheftofsuchin-formation,andsignificantlyincreasestheproblemsassociatedwithenforcingcopyrightsonmultimediainformation[1,2].Theseproblemsarerootedfromtheintrinsicfeaturesofthedigitallyformatedinformation:(1)makingcopiesiseasyandinexpensive;(2)eachcopyisexactlyidenticaltotheoriginal;and(3)dis-tributionofthecopies(e.g.vianetworkorfloppy)iseasyandfast.Forthisreason,creatorsorpublishersofmultimediamaterialsfearprovidingtheirworksforusageinnewmultimediaservices,andareseekingtechnicalsolutionstotheproblemsassociatedwithcopyrightprotectionofmultimediadata.Theseproblemshaverecentlyraisedattentionsinna-tionalIT(informationtechnology)programmes,forexample,NII(NationalInformationInfrastructure)launchedintheUnitedStatesin1993establishedaworkinggrouponIntellectualPropertyRightswhichismainlyconcernedwithcopyrightlawanditsap-plicationandeffectivenessinthecontextofNII[3].Severalprojectsarecurrentlyorhaverecentlybeenconcernedwithcopyrightandrelatedissuesinthedig-italworld,forexample,theECESPRITprojectCITED(Copyrightintransmittedelectronicdata)[4]andCOPICAT(CopyrightOwnershipProtectioninComputerAssistedTraining)[5],andtheECRACEprojectACCOPI(AccessControlandCopyrightProtectionforImages)[6].In[2],wehavesummarizedthatthetechnicalmecha-nismofcopyrightprotectionforinformationindigitalformcanbedividedintothreelevels:accesscontrol,userightcontrol,andlabeling-basedmechanism.Thispaperaddressestheproblemsindevelopingthelastlevelofmechanism,andpresentsaJPEG-basedmeth-odoflabelingimageforcopyrightprotection.Althoughsomeattentionhasbeengiventostegano-graphiclabelingandsimilarproblems[7],thereexistsnotechnologydesignedtosecretlyembedarobustandinvisible(hidden)copyrightlabelinimages.Inpartic-ular,nocurrentmethodadequatelyaddressesthepos-sibilitiesofusingdatacompression,lowpassfilteringand/orsimplychangingthefileformattoremoveanembeddedcode.Therefore,oneofthemaingoalsofthispaperistodefineareasonablesetoffunctionalre-quirementsanddesigncriteriaforanimagecopyrightlabelingmethod,andtofurthermoredemonstratethatthemaindifficultiesinvolvedindesigningsuchasys-temcanbesolved.Thediscussionbeginswithasectionwhichoutlinesthefunctionalityoftheproposedsystemandgeneraldesigncriteriaforthenovelembeddingtechnique.AspecificmethodbasedontheJPEGcompressionstan-dardforembeddingcopyrightlabelsinimagedataisthenpresented.2RequirementsandpossibleattacksInordertobeeffectiveandworkableinamultimediaenvironment,thecopyrightlabelmustbedifficulttoremoveandsurviveprocessingwhichdoesnotseri-ouslyreducethevalueoftheimage.Thisencompassesawiderangeofpossibilitiesincludingformatconver-sions,datacompression,andlowpassfiltering.Inadditiontocopyrightlabelingofbroadcastimages,ap-plicationareasforsteganographiclabelingtechniquesincludecopyrightand/orsecurerecordslabelingofelectronicpublishing,facsimiles,scientificimaging,andmedicalimaging.In:Proc.of1995IEEEWorkshoponNonlinearSignalandImageProcessing(NeosMarmaras,Greece,June20-22,1995)2Requiringthecopyrightlabeltobeareliablepropertyidentificationtoolimposesfollowingbasicfunctionalrequirementsonthesystem:(1)Theimagemustcontainalabelorcode,whichmarksitaspropertyofthecopyrightholder.(2)Theimagedatamustcontainausercode,whichverifiestheuserisinlegalpossessionofthedata.(3)Theimagedataislabeledinamannerwhichallowsitsdistributiontobetracked.Itisassumed,themainpurposeofanyattackwouldbetomaketheembeddedlabelunverifiable.Therearees-sentiallytwogeneralwaystomaketheembeddedlabelunverifiable:(1)altertheimagedatatorenderthecopyrightlabelunreadable,and(2)showthatthelabelisnotareliableidentificationtool.Inadditionseveralpropertiesofdigitaldataanddesignconstraints,whicharerelatedtopreventingattackonthecopyrightlabel,shouldbeconsideredcarefully.First,forgeryofadigitalcopyrightcanonlybepre-vented,ifaforgercannotproduceavalidcopyrightcode.Second,thebasicnatureofdigitalimagesensur-esthatthecopyrightlabelcanbeeasilyalteredifanat-tackercanidentifythelabeldata.Third,mostdigitalimagesfoundinamultimediaenvironmentcanbelowpassfiltered,transformedtoadifferentformatorcolorspace,orcarefullyre-quantizedandcompressedwith-outsignificantlyalteringtheimagesappearanceoraf-fectingitsvalue.Fina