PARTIALENCRYPTIONOFVIDEOFORCOMMUNICATIONANDSTORAGE
ATHESISSUBMITTEDTOTHEGRADUATESCHOOLOFNATURALANDAPPLIEDSCIENCESOFTHEMIDDLEEASTTECHNICALUNIVERSITY
BY
TURANY¨UKSEL
INPARTIALFULFILLMENTOFTHEREQUIREMENTSFORTHEDEGREEOF
MASTEROFSCIENCE
IN
THEDEPARTMENTOFCOMPUTERENGINEERING
SEPTEMBER2003ApprovaloftheGraduateSchoolofNaturalandAppliedSciences.
Prof.Dr.Canan¨OzgenDirector
IcertifythatthisthesissatisfiesalltherequirementsasathesisforthedegreeofMasterofScience.
Prof.Dr.Ays¸eKiperHeadofDepartment
Thisistocertifythatwehavereadthisthesisandthatinouropinionitisfullyadequate,inscopeandquality,asathesisforthedegreeofMasterofScience.
Assoc.Prof.Dr.G¨ozdeBozda˘gıAkar
Co-SupervisorProf.Dr.Fatos¸T.YarmanVuralSupervisor
ExaminingCommitteeMembers
Prof.Dr.A.EnisC¸etin
Prof.Dr.Fatos¸T.YarmanVural
Assoc.Prof.Dr.G¨ozdeBozda˘gıAkar
Dr.CevatS¸ener
Dr.MeltemTurhanY¨ondemABSTRACT
PARTIALENCRYPTIONOFVIDEOFORCOMMUNICATIONANDSTORAGE
Y¨uksel,Turan
M.S.,DepartmentofComputerEngineering
Supervisor:Prof.Dr.Fatos¸T.YarmanVural
Co-Supervisor:Assoc.Prof.Dr.G¨ozdeBozda˘gıAkar
SEPTEMBER2003,66pages
Inthisstudy,anewmethodisproposedtoprotectvideodatathroughpartialen-
cryption.Unlikepreviousmethods,thebitrateoftheencryptedportioncanbe
controlled.Inordertoaccomplishthistask,asimplemodelforthetimetobreak
thepartialencryptionbyachipertext-onlyattackisdefined.Then,theencrypted
bitbudgetdistributionstrategymaximizingthetimesubjecttothebitrateconstraint
isfound.Analgorithmtoestimatethemodelparametersisconstructedanditis
thenimplementedoveranMPEG-4naturalvideocodectogetherwiththebitbudget
distributionstrategy.Theencoderistestedwithvariousimagesequencesandthe
outputisanalyzed.
Inadditiontothedevelopedvideoencryptionmethod,afileformatisdefinedto
storeencryptionrelatedsideinformation.
Keywords:VideoEncryption,MPEG-4,IPMP.
iii¨OZ
˙ILET˙IS¸˙IMVESAKLAMA˙IC¸˙INKISM˙IV˙IDEOS¸˙IFRELEME
Y¨uksel,Turan
Y¨uksekLisans,BilgisayarM¨uhendisli˘giB¨ol¨um¨u
TezY¨oneticisi:Prof.Dr.Fatos¸T.YarmanVural
OrtakTezY¨oneticisi:Doc¸.Dr.G¨ozdeBozda˘gıAkar
EYL¨UL2003,66sayfa
Buc¸alıs¸mada,videoverisininkısmis¸ifrelemeyoluylakorunmasıic¸inyenibiry¨ontem
¨onerilmis¸tir.Daha¨oncekiy¨ontemlerdenfarklıolarak,s¸ifrelenmis¸kısmınboyutu-
nunkontrol¨usa˘glanmıs¸tır.Bunusa˘glayabilmekic¸inkısmis¸ifrelemeyikırmakic¸in
gerekenzamanınbasitbirmodelitanımlanmıs¸tır.S¸ifrelenenkısmınb¨uy¨ukl¨u˘g¨ukısıtı
altındamodelienb¨uy¨ukleyenbitb¨utc¸esida˘gıtımıstratejisibulunmus¸tur.C¸alıs¸ma,
modelparametrelerininkestirimiic¸indebiralgoritma¨onermektedir.Algoritmave
s¸ifrelenmis¸bitb¨utc¸esida˘gıtımıstratejisibirMPEG-4do˘galvideokodlayıcı/c¸¨oz¨uc¨u
¨uzerindegerc¸eklenmis¸vec¸es¸itliimgedizilerindekibitda˘gılımıg¨ozlenmis¸tir.
Videos¸ifrelemey¨ontemininyanısıra,c¸alıs¸madas¸ifrelemeyanbilgilerininsaklan-
masıic¸inbirdosyabic¸imidetanımlanmıs¸tır.
AnahtarKelimeler:VideoS¸ifreleme,MPEG-4,IPMP.
ivACKNOWLEDGMENTS
IamgratefultomyadvisorsDr.Fatos¸T.YarmanVuralandDr.G¨ozdeBozda˘gı
Akarfortheiruniquesupport.Myfamily-at-largeandfriends(inalphabeticalorder)
Nafiz,Murat,Pınar,Faruk,C¸aglar,Emre,O˘guz,Barıs¸,ErsanandUlas¸getequiva-
lentcreditsfortheiracademicandmotivationalsupport.Mythesisimplementation
isbasedonMPEG-4referencesoftwarebyMoMuSysandMicrosoftteams,which
eliminatedtheneedtowriteafrom-scratchMPEG-4naturalvideocodec,although
makingmefeelregretattimes.
vTABLEOFCONTENTS
ABSTRACT.......................................iii
¨OZ.............................................iv
ACKNOWLEDGMENTS................................v
TABLEOFCONTENTS................................vi
LISTOFTABLES....................................ix
LISTOFFIGURES....................................x
LISTOFABBREVIATIONS..............................xii1INTRODUCTION...............................11.1Motivation..............................11.2ContributedWork..........................31.3Organization.............................32BACKGROUNDONVIDEOCOMPRESSIONANDENCRYPTION..42.1VideoCompression.........................42.2MPEG-4NaturalVideoCodingStandard.............62.2.1NaturalVideoCodingToolsProvidedbyMPEG-4..62.2.1.1ShapeCoding................72.2.1.2MotionEstimationandCompensation..82.2.1.3TextureCoding................92.2.1.4Sprites.....................102.2.1.5ScalableVideo................112.2.1.6StaticTextures................122.2.2ErrorResillienceandConcealmentTools.......132.2.3MPEG-4VisualProfilesandLevels...........142.3MPEG-4Systems...........................152.4CryptographyandCryptanalysis.................16
vi
