文献翻译——图像信息隐藏：调查

第1页外文文献资料ImageInformationHiding:AnSurveyI.INTRODUCTIONNowadaysmanyproblemsariseduringtheimagetransformationfromthesendertothereceiver.Strangerscaneasilysnoopintoothersaccountandgetmanysecretinformationevenitwashidedbysomemechanism,withouttheirpermission.Toavoidthisweproposeasecureschemebyusingsteganographyconcept.Steganographymeanshidinginformationinaparticularwaythatpreventsthedetectionofhiddeninformation.Inthisconceptnoonecanfindthatthereisahiddenmessagepresentintheimage,Becauseofinformationishiddenbehindanimageinamatrixform,whichiscreatedbybitmatrixoftheobject.ByusingtheLSBwecanstorethecharacteristicsofparticularpixelsofanimagearemodifiedtostoreamessage.FinallywesendthefinalpictureandcoverimageusedforhiddentheimagetothereceiverJohnson&Jajodia,1998.Atfirstwecalculatetheheightandwidthoftheimage,whichhidetheinformationthenmultiplyitwith8andstoreitinanyvalue.Thenwecalculatetheheightandwidthoftheimagewhichisusedtohidetheobjectandmultiplywitheachother.Thenwecomparethatanswerswithboththeimagewhichisusedtohidetheinformationandwhichisusedtohidetheobject.Theimagewhichisusedtohidetheobjectmusthavegreatervaluethantheotherimage;wechoosetheobjectmustsatisfytheabovecondition.Thentheencodedmatrixismappedwiththeimagebyusingleastsignificantbitmechanism.Leastsignificantbitonlystorestheinformationinsteadofreplacingthepixelofimage.Soscatteringofinformationtakesplacewhiletransferringtheimagesoaccordingtohumaneyethereisnodifferencebetweentheoriginalandstegoimage.Finallysendersendsthebothoriginalandstegoimagetothereceiver.InthereceiversidetogettheinformationthereceivermustdoXORoperationbetweenbytespresentinboththeimage.Comparetheresultwith0*00000000Iftheoutputwillbeyesthenstore0else1inamatrixandthismatrixwillbeequalto第2页thewidthandheightofthepixelmatrixoftheimage.Convertthebitsintobytesuntilallbitsgotutilized.Finallyreceivergetstheinformation.1.1.HistoryofInformationHiding1.2.TheBasicsofEmbeddingThreedifferentaspectsininformation-hidingsystemscontendwitheachother:capacity,security,androbustness.Capacityreferstotheamountofinformationthatcanbehiddeninthecovermedium,securitytoaneavesdroppersinabilitytodetecthiddeninformation,androbustnesstotheamountofmodificationthestegomediumcanwithstandbeforeanadversarycandestroyhiddeninformationFabienA.P.Petitcolasetal.,1999;SabuMThampi,2004;NameerN.EL-Emam,2007.1.3.DiscreteCosineTransformForeachcolorcomponent,theJPEGimageformatusesaDiscreteCosineTransform(DCT)totransformsuccessive88pixelblocksoftheimageinto64DCTcoefficientseach.TheDCTcoefficientsF(u,v)ofan88blockofimagepixelsf(x,y).Asimplepseudo-codealgorithmtohideamessageinsideaJPEGimagecouldlooklikethis:Input:message,coverimageOutput:steganographicimagecontainingmessageWhiledatalefttoembeddoGetnextDCTcoefficientfromcoverimageIfDCT=!0andDCT=!1thenGetnextLSBfrommessageReplaceDCTLSBwithmessagebit第3页EndifInsertDCTintosteganographicimageEndwhile1.4.DetectionTechniquesManyalgorithmswereproposedforestimatingthelengthofthesecretmessageinthecoverimage.Westfeld(2001)proposedtheblindsteganalysisbasedonstatisticalanalysisofPoVs(pairsofvalues).Thismethod,so-calledstatisticaltest,givesasuccessfulresulttoasequentialLSBsteganographyonly.FposedtheRSsteganalysis.ThismethodmakessmallalternationstotheleastsignificancebitplaneinanimagethebyusingthefollowingmethodourprocessKekreetal.,2008;BinLietal.,2011.1.5.SecuritythePacketDecoderThedecodeengineisorganizedaroundthelayersoftheprotocolstackpresentinthesupporteddata-linkandTCP/IPprotocoldefinitions.Eachsubroutineinthedecoderimposesorderonthepacketdatabyoverlayingdatastructuresontherawnetworktraffic.Thesedecodingroutinesarecalledinorderthroughtheprotocolstack,fromthedatalinklayerupthroughthetransportlayer,finallyendingattheapplicationlayer.Speedishighlightinthissection,andthemajorityofthefunctionalityofthedecoderconsistsofsettingpointersintothepacketdataforlateranalysisbythedetectionengineRichardPopa,1998.1.6.InternetProtocolVersionInternetProtocolversion6(IPv6)isanetworklayerIPstandardusedbyelectronicdevicestoexchangedataacrossapacket-switchedinternetwork.ItfollowsIPv4asthesecondversionoftheInternetProtocoltobeformallyadoptedforgeneraluse.AmongtheimprovementsbroughtbyIPv6istheincreaseofaddressesfornetworkeddevices,allowing,forexample,eachcellphoneandmobileelectronicdevicetohaveitsownaddress.IPv4supports4.3109(4.3billion)addresses,whichisinadequateforgivingevenoneaddresstoeverylivingperson,muchlesssupporttheburgeoningmarketforconnectivedevices.IPv6supports3.41038addresses,or51028(50octillion)foreachoftheroughly6.5第4页billionpeoplealivetoday.Normallythepacketsaretransferredfromonesystemtoanotherinpackets.Thepacketsaretransferredthroughthetcpconnectioninamoresecureway.II.HIDEANDSEEK:ANINTRODUCTIONTOSTEGANOGRAPHY2.1.ProblemFormulationInthepast,forthesecuritypurposepeopleusedhiddentattoosorinvisibleinktoconveysteganographiccontent.Todayforhidingpurposecomputerandnetworktechnologiesprovideeasy-to-usecommunicationchannelsforsteganographySarajuP.Mohant,2003;MuhalimMohamedAminetal.,2003.Steganographicsystembecauseoftheirinvasivenature,leavethedetectabletracesinthecovermedium.Thesecretcontentisnotrevealed,butitsstatisticalpropertieschangedsothethirdpartycandetectthedistortionsintheresultingimageMorkeletal.,2005.Theprocessoffindingthedistortionsiscalledstatisticalsteganalysis.2.2.ResearchDesignThispaperexplainsthesteganagraphicsystemsandpresentstherecentresearchindetectingthemthroughstatisticalsteganalysis.SteganographicsystemsfortheJPEGformatseemmoreinteresting,becausethesystemsoperateinatransformspaceandarenotaffectedmyvisualattacks.Visualattacksmeanthatwecanseesteganographicimagesonthelowbitplanesofanimagebecausetheyoverwritethevisualstructures.2.3.FindingTheJPEGimageformatusesadiscretecosinetransformtotransformsuccessive8*8pixelblocksoftheimageinto64DCTcoefficientseach.TheSIJTransactionsonComputerScienceEngineering&itsApplications(CSEA),Vol.1,No.1,March-April2013ISSN:232123812013|PublishedbyTheStandardInternationalJournals(TheSIJ)3TheembeddingalgorithmsequentiallyreplacestheleastsignificantbitofDCTcoefficientswiththemessagedata.ThesameprocessisalsodoneintheJPEGformat.第5页Theauthorandhiscolleagueusedasupportvectormachinetocreateanonlineardiscriminationfunction.Thentheypresentalesssophisticatedbuteasiertounderstandmethodfordeterminingalineardiscriminationfunction.2.4.ConclusionandLimitationsWeofferfourdetailsforourinabilitytofindsteganographiccontentontheinternet.Theyare,Allsteganographicsystemuserscarefullychoosepasswordsthatarenotsusceptibletodictionaryattacks.Maybeimagesfromsourceswedidnotanalyzecarrysteganographiccontent.Nobodyusessteganographicsystemsthatwecouldfind.Allmessagesaretoosmallforouranalysistodetect.Althoughsteganographyisapplicabletoalldataobjectsthatcontainredundancy,weconsiderJPEGimagesonlyforsteganography.2.5.ImplicationsWeinsertthetracerimagesintoeverystegbreakjob.Thedictionaryattackfollowsthecorrectpasswordsfortheseimages.III.STEGANOGRAPHYANDSTEGANALYSIS3.1.ProblemFormulationThegrowthofcomputernetworksandinternethasexploredmeansofbusiness,scientific,entertainment,andsocialopportunities.ThedigitalinformationcanbeeasilyduplicatedanddistributedhasledtotheneedforeffectivecopyrightprotectiontoolssuchassteganographyandcryptographyStefanoCacciaguerraRobertKrenn,2004.3.2.ResearchDesignSecretscanbehiddeninsideallsortsofcoverinformation:text,images,audio,videoandmore.Moststeganographicutilitiesnowadays,hideinformationinside第6页images,asthisisrelativelyeasytoimplementChristianCachin,1998.HidinginformationinsideimagesisapopulartechniquenowadaysShashikalaChannalli,2009.AnimagewithasecretmessageinsidecaneasilybespreadovertheWorldWideWeborinnewsgroups.Themostcommonmethodstomakealterationsintheimagepresentinnoisyareainvolvetheusageoftheleast-significantbitorLSB,masking,filteringandtransformationsonthecoverimage.Thesetechniquescanbeusedwithvaryingdegreesofsuccessondifferenttypesofimagefiles.3.3.FindingMoretechniquesaredevelopedforhidingtheinformationtodetecttheuseofsteganography.Whiletheinformationcanbehiddeninsidetextsinawaythatthemessagecanonlybedetectedwiththeknowledgeofthesecretkey.Awidelyusedtechniqueforimagescanninginvolvesstatisticalanalysis,withthestatisticalanalysisonthelsb,thedifferencebetweenrandomvaluesrealimagevaluecaneasilybedetected.Thestatisticalanalysismethodcanbeusedagainsttheaudiofilestoo,sincethelsbmodificationtechniquecanbeusedonsoundstoo,includingthatseveralotherthingsalsodetected.Whilesteganogramsmaynotbesuccessfullydetectedinsteadofthatweusethestatisticalanalysisfrompossiblecoversources.3.4.ConclusionsandLimitationsSteganographycombinedwithcryptographyisapowerfultoolwhichenablespeopletocommunicatewithoutpossibleeavesdroppersevenknowsthatthereisacommunicationinthefirstplace.Steganographymightalsobecomelimitedlaws,sincegovernmentalreadyclaimedthatcriminalsusethesetechniquestocommunicate.Morerestrictionsareprovidedinthetimeofterroristattacks.3.5.ImplicationsInthefuturethemostimportantuseofsteganographictechniqueswillliein第7页thefieldofdigitalwatermarking.Contentprovidersareeagertoprotecttheircopyrightedworksagainstillegaldistributionanddigitalwatermarksprovideawayoftrackingtheownersofthesematerials.Althoughitwillnotpreventthedistributionitself,itwillenablethecontentprovidertostartlegalactionsagainsttheviolatorsofthecopyrights,astheycannowbetrackeddown.IV.HIDINGENCRYPTEDMESSAGEINTHEFEATURESOFIMAGES4.1.ProblemFormulationSteganographyistheartandscienceofwritinghiddenmessagesinsuchawaythatnoonecantknowabouttheintendedrecipientknowstheexistenceofthemessage.ItsimplytakesonepieceofinformationandhidesitwithanotherKh.ManglemSinghetal.,2007.4.2.ResearchDesignThisprocessexplainstheleastsignificantbitembeddingalgorithmforhidingencryptedmessagesinnonadjacentandrandompixellocationsinedgesofimages.Itfirstencryptsthesecretmessageanddetectsimageinthecoverimage.Thesimplestwaytohidedataonanimageistoreplacetheleastsignificantbitsofeachpixelsequentiallyinthescanlinesacrosstheimageinrawimageformatwiththebinarydata.Anattackercaneasilyseethemessagebyrepeatingtheprocess.Toavoidthistoaddbettersecurity,themessagetobehiddenisfirstencryptedusingthesimplifieddataencryptionstandardandthenitisdistributedrandomlybyapseudorandomnumbergeneratoracrosstheimage.4.3.FindingManyalgorithmsareusedtoestimatethelengthofthesecretmessageinthecoverimage.Heretheyproposetheblindsteganalysisbasedonstatisticalanalysisofpairsofvalues.Thismethodiscalledstatisticaltest.Theyproposethedetectionalgorithmbasedonhigherorderstatisticsforseparatingoriginalimagesfromstegoimages.第8页Blinddetectionalgorithmthatestimatestheaccuracyofembeddedmessagethroughtheanalysisofthevariationoftheenergyresultantfromthelsbembedding.4.4.ConclusionsandLimitationsThepaperdescribedanovelmethodforembeddingsecretmessagebitinleastsignificantbitofnonadjacentandrandompixellocationsinedgesofimages.Nooriginalcoverimageisrequiredfortheextractionofthesecretmessage.IthasbeenshownexperimentallythattheblindLSBdetectiontechniquelikethegradientenergymethodcouldnotestimatethelengthofthesecretmessagebitsaccuratelyfortheproposedalgorithm.4.5.ImplicationsThemessagetobehiddenintheimagewasfirstencryptedusingtheS-DESalgorithm.Thenestimatethelengthofthesecretmessagebitsbythegradientenergytechnique.Gradientenergytechniquecouldnotestimatethelengthofthesecretmessagebitaccurately.4.6.AdvantagesAmessageinciphertext,forinstance,mightarousesuspiciononthepartoftherecipientwhilean“invisible”messagecreatedwithsteganographicmethodswillnot.Watermarkingiseither“visible”or“invisible”.Althoughvisibleandinvisiblearevisualtermswatermarkingisnotlimitedtoimages,itcanalsobeusedtoprotectothertypesofmultimediaobject.Insteganographiccommunicationsendersandreceiversagreeonasteganographicsystemandasharedsecretkeythatdetermineshowamessageisencodedinthecovermedium.Withoutthekeytheycantidentifythesecretmessage.InsteganographicsystemstheimagesweusedforhidingmaybeJPEGformatseemmoreinterestingbecausethesystemsoperateinatransformspaceandarenotaffectedbyvisualattacks.第9页4.7.DisadvantagesEncryptionprotectscontentsduringthetransmissionofthedatafromthesendertoreceiver.However,afterreceiptandsubsequentdecryption,thedataisnolongerprotected.Byusingthesecretkeywearedeliverthesecretmessagesaferatthesametimeifanyhackerfindsthekeythentheycaneasilygetthesecretmessage.Visualattacksmeanthatyoucanseesteganographicmessagesonthelowbitplanesofanimagebecausetheyoverwritevisualstructures;thisusuallyhappensinBMPimages.V.PROPOSEDSYSTEMSteganographyisusedtohidetheinformationintheformofmultimediaobjectsconsideringtwothingsthatissizeanddegreeofsecurity.Thisconceptassiststhescatteringofinformationatthetimeofhidingandimplementsthenontraceablerandomizationtodifferentiatefromtheexistingwork.Doubleembeddingisdoneformoresecurity.5.1.AdvantagesSteganographyistheconceptofhiddenmessagesinsuchawaythatnooneapartfromtheintendedrecipientknowsoftheexistenceofthemessage.Heredoubleembeddingtakesplace.Soitissafer.Itdoesnthaveanykeytodecrypttheimage.Sothehackerhasnochancetogetthemessageinthisway.Thisconceptdealsthattheeavesdropperswillnothaveanysuspicionthatmessagebitsarehiddenintheimageandstandardsteganographydetectionmethodscannotestimatethelengthofthesecretmessagecorrectly.Withsteganographywecansendmessageswithoutanyonehavingknowledgeoftheexistenceofthecommunication.Therearemanycountrieswhereitisnotpossibletospeakasfreelyasitisinsomemoredemocraticcountries.Thenitistheeasymethodtosendnewsandinformationwithoutbeingcensoredandwithoutthefearofthemessagesbeing第10页interrupted.5.2.DisadvantagesThisconceptisappliedonlyforimagesnotforaudioandvideofiles.Thereceivermustknowabouttheleastsignificantbittechnique.VI.CONCLUSIONHereweconcludethatwepreventthedetectionofhiddeninformationbyusingsteganographyconceptandproposeaTheSIJTransactionsonComputerScienceEngineering&itsApplications(CSEA),Vol.1,No.1,March-April2013ISSN:232123812013|PublishedbyTheStandardInternationalJournals(TheSIJ)5secureschemeforimagetransformation.HereweuseleastsignificantBitmodificationtechniquetoinserttheimageintoanotherimageforhiddenpurpose.Imageishiddenintoanotherimageisthetechniqueweintroducedinourpaper.Inothersecuritymechanismsthestrangerscaneasilystolethemessagefromtheimagebyrepeatingtheprocess.Butinourtechniquewithoutthestegokeywecantextractthemessagefromtheimage.Thistechniquefacilitatesthescatteringofinformationatthetimeofhiding;thisisnewmethodweproposedinourpaper.VII.FUTUREENHANCEMENTApartfromthis,anykindoffutureendeavorinthisfieldwilldefinitelyrouteitapathtodesignasecuresystemusingtheproposedalgorithmforbothInternetandMobileCommunicationTechnology.Thescatteringofinformationtechniqueisusedatthetimeofhidingisusefulformanynewspapersbasedonsteganography.Developmentincovertcommunicationsandsteganographywillresearchinbuildingmorerobustdigitalwatermarksthatcansurviveimagemanipulationandattacks.Wehopesomecommercialandeffectiveschemeswillbeavailableinfuture.Inthenearfuture,themostimportantuseofsteganographictechniqueswillprobablylieinthefieldofdigitalwatermarking.Contentprovidersareeagertoprotecttheircopyrightedworksagainstillegaldistributionanddigitalwatermarksprovideawayoftrackingtheownersofthesematerials.InfuturewecanusethispaperintheGovernment,SoftwareCompany,Detectiveagenciesetc.第11页Thesamestepisinvolvedtoembedtheinformationandsendtoparticularuser.REFERENCES1N.F.Johnson&S.Jajodia(1998),“ExploringSteganography:SeeingtheUnseenComputer”,Vol.31,No.2,Pp.2634.2RichardPopa(1998),“AnAnalysisofSteganographicTechniques”,Pp.117.3ChristianCachin(1998),“AnInformation-TheoreticModelforSteganography”,InformationHiding,LectureNotesinComputerScience,Vol.1525,Pp306-318.4FabienA.P.Petitcolas,RossJ.Anderson&MarkusG.Kuhn(1999),“InformationHidingASurvey”,ProceedingsoftheIEEE,SpecialIssueonProtectionofMultimediaContent,Vol.87,No.7,Pp.10621078.5A.Westfeld(2001),“F5-ASteganographicAlgorithm:HighCapacityDespiteBetterSteganalysis”,Proceedingsof4thInternationalWorkshopInformationHiding,Pp.289302.6SarajuP.Mohant(2003),“DigitalWatermarking:ATutorialReviewNielsProvos,PeterHoneyman,HideandSeek:IntroductiontoSteganography”.7MuhalimMohamedAmin,SubariahIbrahim,MazleenaSalleh&MohdRoziKatmin(2003),“InformationHidingusingSteganography”,InformationHidingusingSteganographyApproach,Vol.71847,Pp.134.8StefanoCacciaguerra&StefanoFerretti(2003),“DataHiding:StegnographyandCopyrightMarking”,DepartmentofComputerScience,UniversityofBologna,Italy,Pp.130.9RobertKrenn(2004),“SteganographyandSteganalysis”.10SabuMThampi(2004),“InformationHidingTechniques:ATutorialReview”,ISTE-STTPonNetworkSecurity&Cryptography,LBSCE2004.11T.Morkel,JHPEloff&MSOlivier(2005),“AnOverviewofImageSteganography”,ProceedingsoftheFifthAnnualInformationSecuritySouthAfricaConference(ISSA2005),Sandton,SouthAfrica.12NameerN.EL-Emam(2007),“HidingaLargeAmountofDatawithHighSecurityusingSteganography”,AlgorithmJournalofComputerScience,Vol.3,No.4,Pp.223232.13Kh.ManglemSingh,S.BirendraSingh&L.ShyamSundarSingh(2007),“HidingEncryptedMessageintheFeaturesofImages”,InternationalJournalofComputerScienceandNetworkSecurity(IJCSNS),Vol.7,No.4.14H.B.Kekre,ArchanaAthawale&PallaviN.Halarnkar(2008),“IncreasedCapacityofInformationHidinginLSBsMethodforTextandImage”,WorldAcademyofScience,EngineeringandTechnology,Pp.910913.15ShashikalaChannalli(2009),“Steganography:AnArtofHidingData”,InternationalJournalonComputerScienceandEngineering,Vol.1,No.3,Pp137141.16BinLi,JunhuiHe,JiwuHuang,YunQingShi(2011),“ASurveyonImageSteganographyandSteganalysis”,JournalofInformationHidingandMultimediaSignalProcessing,Vol.2,No.2,Pp.142171.D.SaravanancurrentlyworkingasanAssistantProfessorinthedepartmentofcomputerapplicationsinSathaybamaUniversity,Chennai.Hisareasofinterestareimageprocessing,datamining,DBMS.Hehaspublishedpaperinfivenationalconferences&twointernationaljournalsinthefieldofdatamining.A.RonoldDoniworkingasanAssistantProfessorinthedepartmentofcomputerapplicationsinSathaybamaUniversity,Chennai.Hisareasofinterestareimageprocessing,datamining,DBMS.Hehaspublishedpaperinthreenationalconferences&oneinternationaljournalinthe