文献翻译——音频信息隐藏算法的研究和实现

第1页外文文献资料ResearchandimplementationoftheaudioinformationhidingAbstract:Informationhidingtechniquehasbecomehotspotsresearchinrecentyears,themajorcontentofthehidingtechniqueisseektothealgorithmthatinsertthesecretinformationintothehostinformationThehostinformationmaybethetext，theimage，theaudioetcRecently，withthedevelopingofinformationhidingtechnique，theaudiodigitalwatermarktechniqueisbecomingahottopicItcanbeusedtoprotectingcopyright，hidingcommunicationbyembeddingthesecretinformationintotheaudiofileTheaudiodigitalwatermarktechniquesarediscussedindetailinthispaper.Inthispaperwepresentanoveltechniqueforembeddingdigitalwatermarksintodigitalaudiosignals.Watermarkingisatechniqueusedtolabeldigitalmediabyhidingcopyrightorotherinformationintotheunderlyingdata.Thewatermarkmustbeimperceptibleandshouldberobusttoattacksandothertypesofdistortion.Inaddition,thewatermarkalsoshouldbeundetectablebyallusersexcepttheauthorofthepiece.Finally,discussestheDWT(discretewavelettransform)domainofanaudiowatermarkembeddingandextractionalgorithm.Keywords:informationhiding；audioinformationhiding;wavelettransform;digitalwatermarking;1.IntroductionIntodaysdigitalandinformationtechnologyundertheconditionofmoremature,becauseoftherelationshiptotheinformationsecuritytothecountrySecuritytocommercialsecretsandpersonalprivacy,andmanyotheraspects,sotheinformationsecuritytechnologyfromthebeginningofbirthhasreceivedwidespreadattentionandconsiderableattention.Asanimportantbranchofinformationsecurity,theinformationhidingtechnologyhasgoodconcealmentandsimplicityandgraduallytobecomeoneofresearchhotspots第2页inthefieldofinformationsecurity.Informationhidingisanemerginginthefieldofinformationsecurityisalsoveryimportantfieldofstudy,mainlystudythespecificinformationhidingindigitalinformation(carrier)methodsinthehost.Undertheairspaceortransformdomain,thetechnologyismainlyinthehostinformationformat,size,qualityunchangedunderthepremiseoftheclearinformationtoacertainprocessingalgorithmfusiontothehostinformation,andthefusion,theexternalformofthehostinformation,inthecaseofwithoutspecialhandlingplaintextinformationisnotvisible.Onlywithclearinformationofhostseparationalgorithmtotheprocessingofinformationwilldefinitelyreturnallinformationcondition.Bookinformationtherearetextfiles,thebitmapfile,videoandaudiofiles,fornow,howaboutinatextfile,thebitmapfileandstudyalotofvideofileshiddeninformation,andforaudioinformationhidingtechnologyisverylittlereported.Digitalwatermarkingtechnologyistheinformationhidingtechnologyinthetypicalapplicationofcopyrightprotection,therearemanyscholarsinvariousacademicjournalsofstoriesaboutthedigitalwatermarkingtechnology,digitalwatermarkingtechnologyismainlydividedintotheairspace,transformdomainandspreadspectrumtechnology,buteachhasitsdrawbacks.Thispap-erdiscussestheDWT(discretewavelettransform)domainofanaudiowatermarkembeddingandextractionalgorithm.2.Digitalwatermarkingtechnology2.1.TheresearchbackgroundAlongwiththedevelopmentofdigitaltechnologyandInternet,variousformsofmultimediadigitalworksarepublishedintheformofnetwork,digitalworks,however,theconvenienceandsecurityiscoexist,itwouldbelowcost,highspeedcopyandspread,suchascreatorsandusersprovidesagreatconvenience,butthesefeaturesareeasytobeusedbythepirates,therefore,thedigitalworkstoprotect,byavarietyofmeanstopunishviolatorshasbecomeaveryurgentwork.Similarlegalworksinadditionto第3页thetraditionalcopyrightprotectionandmanagement,alsoshouldaccordingtothecharacteristicsofthedigitalworksitselftoprovidethetechnicalprotection.Theresearchofdigitalwatermarkingisdevelopedrapidlyunderthisapplicationneeds.Digitalwatermarkingisaneffectivedigitalproductscopyrightprotectionanddatasecuritymaintenancetechnology.Itisofparticularsignificanceoftag(watermark),themethodofusingdigitalembeddedhiddenindigitalimage,audio,documents,books,videoandotherdigitalproducts,inordertoprovetheownershipofthecreatorforitsproducts,andasevidenceofidentification,prosecutetheillegalinfringement,atthesametime,throughtothewatermarkdetectionandanalysistoensurereliabilityandintegrityofthedigitalinformationtointellectualpropertyprotectionanddigitalmultimediaanti-counterfeiteffectivemeans.Digitalwatermarkingtechnologybesidesshouldhavethegeneralcharacteristicsofinformationhidingtechnology,withitsinherentcharacteristicsandresearchmethods.2.2.ThecharacteristicsofdigitalwatermarkingDigitalwatermarkisembeddedintotheprotectedobjects(suchasstaticimages,video,audio,etc.),someofthecardtothecopyrightofdigitalinformation,canbetheauthorsname,serialnumber,companylogoetc.Digitalwatermarkingtechnologyhasitsinherentcharacteristicsandresearchmethods.Forexample,fromthepointoftheinformationsecurity,thehiddeninformationifiseroded,systemcanberegardedassafe,becausethesecretinformationdidnotleak,however,inthedigitalwatermarkingsystem,thelossofthehiddeninformationmeansthecopyrightinformationismissing,andlosethefunctionofcopyrightprotection.Sothedigitalwatermarkingsystemmusthavestrongerrobustness,securityandtransparency,etc.(1)Transparency(hidden):throughaseriesofhiddenprocessing,thetargetdatamustbenoobviousdropqualitativephenomenonandhiddendatacantpeopleseeorhear.(2)Robustness(robustness):referstoresistavarietyofprocessingoperationsandmaliciousattackswithoutcausingwatermarkinformationloss.Theso-calledoperationsinclude:intheprocessoftransmissionchannel第4页noise,filtering,enhanced,losscompression,geometrytransformation,D,A,orMDconversionandsoon.Theso-calledattackinclude:tamperedwith,forge,removethewatermark,andsoon.Digitalwatermarkingoriginatedininformationhidingtechnology;thiscanbeconfirmedfromitshiddenrequest.(3)Securityhiddenposition:referstothewatermarkinformationhidingwithinacontentofthetargetdata,ratherthanthefilesthefirstplace,thispreventsforfileformatconversionandruinedthewatermark.(4)Noambiguity:recoverthewatermarkorwatermarkjudgmentshouldbeabletodeterminethattheresultoftheownershipofthemultipleownershipdisputeswillnotoccur.(5)General(ease):referstothewatermarkalgorithmshouldbeapplicabletoavarietyoffileformatsandmediaformat.2.3.ThetraditionalaudiowatermarkinformationSofar,morematurerecognizedaudioinformationhidingtechnologyhasfourkinds:theleastimportantmethod;Echohidingmethod;Phaseencodingmethod;Spreadspectrummethod.（1）TheleastimportantmethodLeastsignificantbit(LSB)methodisoneofthesimplestdataembeddingmethod.Anysecretdatacanberegardedasastringofbinarybitstream,andaudiofilesofeachsamplingdataisalsoexpressedinabinarynumberto,socaneachsamplingvaluesoftheleastimportantbits(inmostcasesitslowest)replacewithrepresentativeofsecretdatabits,inordertoachievethepurposeofembeddingsecretdataintheaudiosignal.Thismethodadvantageis:easytoimplement;Audiosignalcanbeencodedinthelargeamountofdata;Instreamencryptionthedataitselfisencryptedandembeddedprocessrespectively,itssecurityreliesonthekey;Informationembeddingandextractionmethodissimple,fastspeed.Weakness:theresistancetochannelinterferenceanddatamanipulationisverypoor,noise,compression,filtering,theresamplewilldestroythewatermarkingdata,sothepracticalvalueissmaller.(2)WatermarkingalgorithmbasedontheechoEchoHidingistheuseoftheEchoareintroducedtothesecretdatais第5页embeddedintothecarrier.Itusesthecharacteristicsofhumanauditorysystem:shieldingeffectafteraudiosignalintimedomain,theweakbecomeimpossibletohearaftertheictusvanished.Vectordata,andaftertheechohidingsecretdatafortheear,theformerislikeheardthevoicefromtheheadset,noecho,andthelatteristohearthesoundfromthespeakerisproducedbythespaceoftheecho.Echoalgorithmisdifferentfromothermethods,therefore,istoputthesecretdataasthecarrierofenvironmentalconditions,ratherthanasarandomnoiseisembeddedintothecarrierdata,sothismethodhasgoodtransparencyandrobustness.(3)SpreadspectrummethodIntheusualcommunicationchannel,tomaintaineffectivebandwidthandreduceenergy,alwaysneedtheinformationfocusedonspectrumasnarrowaspossible.Anddrawlessonsfromtheideaofspreadspectrumcommunication,caninthecodingofaudiodatastreamwhendistributethesecretdatainspectralcomponentasmuchaspossible.Inthisway,evenif:thereiscertainfrequencyinterference,alsowontaffectthereceivingdata.TherearealotofSpreadSpectrumcommunicationway,commonlyusedhavewinSequenceSpreadSpectrumcode(DirectSequenceSpreadSpectrumEncodingtheDSSS).UsingsymmetrickeyalgorithmusedinDSSSsystem,whichUSESthesamekeytoencodeanddecode.Thekeyisapseudorandomnoise,theidealpseudorandomnoiseiswhitenoiseanditsfrequencyresponseinthefrequencyrangeisgood.Keyusedtocompileinformationandadjustthesequenceintoaspreadspectrumsequence.Secretdatawasamplifiedbycarrierandpseudorandomsequence,thelatterhasaverywidespectrum.Asaresult,thedataofspectrumissplitintopossiblewavelengths.Drawlessonsfromtheideaofspreadspectrumcommunication,hiddendataflowcanbeexpandedtoasmuchaspossible,oraspecifiedfrequencybandwidth,inordertoachievethepurposeofhiddendata.AtpresentUSESthespreadspectrumtechnologyisthedirectsequencespreadspectrum,treatedwitherrorcorrectioncodingsequenceofpseudorandombinarypulseforaudiosignalmodulation,makesthewatermarkdataextendacrosstheentireaudiospectrum,oronthespecifiedfrequencyband.Tocontrolelectricalnoisefrequency,notbythehumaneardetection,mustfirstmodulationsignal第6页attenuation,makeadditiverandomnoiseaddedtotheoriginalsignal,extractionusingmatchedfiltertothewatermarkinformationretrieval,matchedfiltercoefficientisconsistentwiththereversalofthespreadspectrumsequence.Thistechniquehashighrobustnessandsecurity.(4)PhaseencodingmethodPhasecodingisoneofthemosteffectivecodingmethods.Itmakefulluseofthehumanauditorysystem(HAS)acharacteristic:theearofabsolutephasesensitivityandsensitivitytotherelativephase.Basedonthischaracteristic,usethebehalfofthesecretdataofreferencephasetoreplacetheoriginalaudiosectionoftheabsolutephaseandtoadjustotheraudiosegments,tokeeptherelativephasebetweentheparagraphsnotchange.Phaseencodingadefectis:whenonbehalfofthesecretdatareferencephasechangesharply,therewillbeobviousphasedeviation.Itnotonlyaffectstheconfidentialityofconfidentialinformation,butalsowillincreasethedifficultyofthereceiverdecoding.Acauseofthephasedeviationistousethereferencephaseinsteadoftheoriginalphaseandthedeformation,anotherreasonisthattheoriginalaudiosignalfrequencyphasechangestoofast,soyoumusttrytomaketransformationgentlytodecreasethedeformationandphasedeviationofaudio.Gentlytomaketransformation,willhavetoleavesomespacebetweenthedatapoints,whichleadtoistoreducetheinfluenceoftheembeddedaudiobitrate,ontheotherhand,inordertoenhancetheanti-interferenceabilityofthecode,shouldbetomaximizethedifferencebetweenthereferencephase,thereforeusuallychoose-PI/2insteadof0,thePI/2insteadof1.Improvedinordertomaketheinfluenceofthephasedeviation,needtobeinwithacertainintervalbetweeneachdatapointtomaketheconversionflattensout,butitwillreducethebandwidth.Soyoumustcompromisebetweendataembeddingquantityandembeddingeffect.Generallyspeaking,theamountofembeddingphaseencodingis8BPS32BPS.2.4.AudiowatermarkinginformationhidingschemeObservethata“pirate”candefeatawatermarkingschemeintwoways.Hemaymanipulatetheaudiosignaltomakethewatermarkundetectable.第7页Alternatively,hemayestablishthatthewatermarkingschemeisunreliable,e.g.,thatitproducestoomanyfalsealarmsbydetectingawatermarkwherenoneispresent.Bothgoalscanbeachievedbyaddinginaudiblejammingsignalstotheaudiopiece.Therefore,theeffectivenessofawatermarkingschememustbemeasuredbyitsabilitytodetectawatermarkwhenoneispresent(probabilityofdetection)andtheprobabilitythatitdetectsawatermarkwhennoneispresent(probabilityofafalsealarm)inthepresenceofjammingsignalsandsignalmanipulations.Severaltechniquesfordatahidinginimageshavebeendeveloped1、3、4、5、6.Amethodsimilartooursisproposedin2,wheretheNlargestfrequencycomponentsofanimagearemodiedbyGaussiannoise.However,theschemeonlymodifiesasubsetofthefrequencycomponentsanddoesnottakeintoaccountthehumanvisualsystem(HVS).Theaudiowatermarkweproposehereembedsthemaximumamountofinformationthroughoutthespectrumwhilestillremainingperceptuallyinaudible.Itiswell-knownthatdetectionperformanceimproveswiththeenergyofthesignaltobedetected.Therefore,weeffectivelyimprovetheperformanceofthewatermarkingschemebyincreasingtheenergyofthewatermarkedsignalwhilekeepingitinaudible.In7、8,wepresentedanoveltechniqueforembeddingdigitalwatermarksintoaudiosignals.Notethatourapproachissimilartothatoftheapproachof1,inthatweshapethefrequencycharacteristicsofaPN-sequence.However,unlike1weuseperceptualmaskingmodelsoftheHAStogeneratethewatermark.Inparticular,ourschemeforaudioistheonlyonethatusesthefrequencymaskingmodelsoftheHASalongwiththetemporalmaskingmodelstohidethecopyrightinformationinthesignal.Wealsoprovideastudyofthedetectionperformanceofourwatermarkingscheme.OurresultsindicatethatourschemeisrobusttolosscodingdecodingDA-ADconversion,signalresembling,andfiltering.Inthispaper,wepresentfurtherresultsshowingthatourschemeisrobustwhenthewatermarkswhicharecomposedofmultiplePN-sequencesandisrobustinthepresenceofaudibledistortionsduetovectorquantization.Finally,observethattheapproachdescribedhereforwatermarkingaudiosignalscanalsobeusedtowatermarkimageandvideodatawithappropriate第8页modificationsandextensions(e.g.7,9).2.5.ThewatermarkdesignThebasicwatermarkingstepstartswithaPN-sequenceMaximumlengthPN-sequencesthatareusedinourwatermarkingschemebecausetheyprovideaneasywaytogenerateauniquecodeforanauthorsidentification.Likerandombinarysequences,PNsequenceshave0sand1sthatoccurwithequalprobabilities.Theautocorrelationfunction(ACF)ofsuchasequencehasperiodNandisbinaryvalued10.BecauseoftheperiodicityoftheACF,thePNsequenceisself-clocking.Thisallowstheauthortosynchronizewiththeembeddedwatermarkduringthedetectionprocess.Thisisimportantifthesignaliscroppedandresample.Togeneratethewatermark,wefirstcalculatethemaskingthresholdofthesignalusingtheMPEGAudioPsychoacousticModel1,11.Themaskingthresholdisdeterminedonconsecutiveaudiosegmentsof512samples.EachsegmentisweightedwithaHammingwindow.Consecutiveblocksoverlapby50%.Themaskingthresholdisthenapproximatedwitha10thorderall-polefilterM(w),usingaleastsquarescriterion.ThePN-sequenceseq(w),isfilteredwiththeapproximatemaskingfilter,M(w),inordertoensurethatthespectrumofthewatermarkisbelowthemaskingthreshold.SincethespectralcontentoftheaudiosignalchangeswithtimewatermarksaddedtodifferentblockswillbeingeneraldifferenteveniftheyaregeneratedfromthesamestartingPN-sequence.However,itispreferabletousedifferentPNsequencesfordifferentblockstomakethestatisticaldetectionbyanunauthorizeduserofthewatermarkmoredifficult.NotealsothatusinglongPN-sequencesorembeddinglongcryptographicdigitalsignaturesalsohelpsinthatrespect.Thetimedomainweightingoperationattenuatestheenergyofthecomputedwatermark.Inparticular,watermarksobtainedasabovehaveamplitudesthataretypicallysmallerthanthequantizationstepsize.Therefore,thewatermarkwouldbelostduringthequantizationprocess.Notealsothat,asobservedearlier,detectionperformanceisdirectlyproportionaltotheenergyofthewatermark.Wehavefoundthatitispossibletoprevent第9页watermarklossduringquantizationandimprovedetectionperformancebyamplifyingthewatermarkby40dBbeforeweightingitinthetimedomainwiththerelativeenergyofthesignal.Wehavefoundexperimentallythatthisamplificationdoesnotaffecttheaudibilityofthewatermarkbecauseoftheattenuationeffectofthetimedomainweightingoperation.3.Thedomainofwavelettransform(DWT)method3.1.Thegeneralprocessofusingwaveletsignalprocessing（1）Sampling:ifthesignaliscontinuous,somustbeabletocapturetheoriginalsignalnecessarydetailsofsamplingrate.Theapplicationofdifferentdecisionsamplingrates.SuchasinordertoreproduceBeethovensninthsymphony,lifelike,besuretocapturetoclosetothehumanearhearinglimitofabout20kHzfrequencysignal,thatistheNyquistfrequency.Knowbyexperiencethatthesamplingrateshouldbe2timesoftheNyquistfrequency,whichis40KHZ,thisstepintheexperimentwedontneedtodo,becauseweusetheaudiosamplinghadbeendone.（2）Decomposition:aftersampling,anappropriatelevelofdecomposition,thewaveletcoefficientatalllevelsandtheapproximatecoefficientforaminimumlevel,isthenextsteptodealwiththeobjectofthefactorset.（3）Signalprocessing:byabandoningthesignificantcoefficientscanbecompressedsignal,orinsomeway,makethesignalfilteringanddenoising,theoutputcanbestoredandreconstructiontorestoreimmediatelyafterprocessingthesignal.3.2.Themaincontentofthealgorithm（1）TochooseapairofM1*M2binaryimageaswatermarking,canbeexpressedasP=P(i,j),0iM1,0jM2，P(i,j)(0,1).Becauseoftheaudiosignalisone-dimensional,totheimagewatermarkembeddedwatermarkimagemustbereducedtoonedimension,namelyS=S(k)=P(i,j),0iM1,0jM2,K=i*M1+j,0kM1*M2-1.(2)Foraudiosignalwaveletdomaintransformationinthefirstplace,in第10页thispaper,theaudiosignalisthreelayerswavelettransform,high-frequencycoefficientsandlow-frequencycoefficientsobtainedrespectively,andthenextractthehighfrequencycoefficientsandlow-frequencycoefficients.Herecanusewavelettransformfunction,wavedec(),appdeof(),detcoef()transformationandextractioncoefficient().Afterthedimensionofwatermarkcanmakeactualwatermarkembedding,heresetbysettingaquantitativefactortodeterminethespecificwayofembedded.Bymeansofaudiosignallowfrequencycoefficientandtheratioofquantizedcoefficientsintegermodulo2,comparingwithwatermarkimageofeachjudgment,todeterminetheembeddingform.Willworkwithallembeddedwatermarkimagesizeofthenumberoflowfrequencycoefficient,andthenthewavelethigh-frequencycoefficientswithlowfrequencycoefficient,whichcontainsthewatermarktoinversewavelettransform,getcontainaudiowatermarking,thisprocessbywaverec()functionimplementation.(3)Correspondstothewatermarkembedding,watermarkextractionprocessisbasicallytheinverseprocessofwatermarkembeddingprocess.Becausethealgorithmistoextract,sodontneedtheoriginalaudioinformation,butneedthewatermarkinformation.Toembedwatermarkaudioinformationwavelettransform,extractthelowfrequencycoefficientandarresttransform,embeddingprocedurecanextracttheembeddedinformation,ldtransformagain,youcangetthewatermarkinformation.第-11-页中文翻译稿音频信息隐藏算法的研究和实现【摘要】：信息隐藏技术已经成为近年来的研究热点，信息隐藏技术的研究内容主要是寻求向载体对象中添加嵌入信息的算法。载体对象可以是文本、图像或音频等，随着信息隐藏技术的发展，目前，音频数字水印技术是近年来的研究热点之一，该技术通过向音频文件中嵌入秘密信息以达到版权保护、隐蔽通信等目的。本文对音频数字水印技术做了全面的研究，