可信平台模块P2P网络安全分布研究(IJCNIS-V3-N2-4)

I.J.ComputerNetworkandInformationSecurity,2011,2,26-33PublishedOnlineMarch2011inMECS()Copyright©2011MECSI.J.ComputerNetworkandInformationSecurity,2011,2,26-33SecuringtheDistributionsinP2PNetworkswithTrustedPlatformModulesHaoLiStateKeyLaboratoryofInformationSecurity/InstituteofSoftware/ChineseAcademyofSciences,Beijing,ChinaEmail:[e-mail],QianyingZhang,andShijunZhaoStateKeyLaboratoryofInformationSecurity/InstituteofSoftware/ChineseAcademyofSciences,Beijing,ChinaEmail:{qin_yu,zhangqy,zhaosj}@is.iscas.ac.cnAbstract—WepresentanovelsolutionthatallowsoneplatformtosecurelydistributeorredistributedigitalcontentstoanotherinP2Pnetworks.Thesolutionincludesthreeprotocols(distributionprotocol,usageprotocol,redistributionprotocol)whichareallbasedonplatformswithTrustedPlatformModules(TPMs).Itmaintainstheconfidentialityandfreshnessofdigitalcontentsduringtheprocessesofdistribution.Givenanideal(tamper-proof)trustedplatform,thesolutioncanevenwithstandattacksbydishonestusersduringtheprocessesofusage.Moreover,itcanalsobeusedtoredistributen-time-usedigitalcontentoffline,soitismoreflexibleandscalablethanotherrelateddistributionsolutionstoenablewidespreaddeployment.Lastly,byaddingafewsimplefeaturestoTPMs,oursolutioncaneasilypreventthemalicioussenderandreceiverfromcolludingwhentheredistributiontakesplace,sowecanensurethattheycannotgainmorethanapreviouslydefinedamountofrightswithoutcontactingthecontentprovider.IndexTerms—TrustedComputing,peer-to-peer,TPM,redistribution,n-time-usedigitalcontentI.INTRODUCTIONInthetraditionalclient-serverarchitectures,thereisalwaysatrustedserverandaclientthatconnectstotheservertoacquirecertaincontents.Thecontentsintheservercanbeprotectedbyvariouseffectivesecuritymechanisms,butitisdifficulttoprotectthemwhentheyarebeyondthecontrolofaserver.Sinceclientsareoftendevicesthatarelogicallyandphysicallyunderthecontroloftheirowners,clientuserscanattackandcircumventtheprotectionmechanismseasily.ItwillbemorecomplexintheP2Pdistributionarchitecturesbecausethepartycanbebothclientandserveratthesametime.Thatis,alltheinterestsofdifferentpartiesshouldbereflectedintheP2Parchitectures.Fortunately,theTrustedComputingGroup(TCG)hasspecifiedaTrustedPlatformModule(TPM)actingasatrustedthirdpartywhichcanbeusedtobuildtrustrelationshipsbetweenusersintheP2Pnetworks.Andnowadays,TPMshavebeenembeddedinmanypersonalcomputers.Sowecangetanidealtrustedplatformbasedonsuchachip.Andthetechnologiesofbuildingsuchplatformshavebeenfocusedonforseveralyears,suchas[1-8].Inthispaper,weneedsuchtrustedplatformstoprovidesecureenvironmentsinwhichourprotocolsrun.Hencewesupposethatanidealtrustedplatformhasalreadyexisted,andhowtobuildsuchaplatformisbeyondthescopeofthispaper(thereadercangetmoreabouthowwebuildatrustedplatforminourpreviouswork[3,5]).Andtomotivateourwork,wemaketwodefinitionshere:n-time-usedigitalcontentandredistribution.N-time-usedigitalcontentsarecontentsthatcanbeusedonlyntimeswhichispreviouslydefinedbythecontentprovider.Moreover,theusercanconsumethemintheirownplatformswithoutcontactingtheprovider.Redistributionisaprocessinwhichthecontentuser(sender)sendshisorherdigitalcontentstoothers(receiver).IntheP2Parchitectures,thereisnocentralserverwhichisalwaysonline.Sowemustensurethatthesenderandreceiverfollowthepoliciesofcontentproviderwhentheredistributiontakesplaceoffline.Moreover,ifthecontentisann-time-usedigitalcontent,theproblemwillbecomemorecomplex.Inthispaper,weshowhowtheseproblemscanbesolvedusingminimaltrustedhardwarefunctionalityprovidedbyTPMs.Contribution.Wepresentasolutionforoffline,peer-to-peercontentsharingwhichallowsredistributionofn-time-usecontent.ThebasicprincipleistouseTPMmigratablekeyswithtransportsessionlogs(acting,inessence,asuse-countcertificates)inordertopreventreplayandaman-in-the-middlestyleattack.AfurtherprocessisdescribedforpreventingcollusionbytwopartiesintheP2PnetworkswhichneedamodificationtotheTPM.Andfinally,wegiveaninformalanalysisofoursolution’ssecurity,andtheresultsofperformanceexperiments.Outline.Therestofthispaperisorganizedasfollows,inSection2,weprovideasummaryofthoseaspectsoftrustedcomputingthatarerelevancetothispaper.InSection3,weidentifythesecurityrequirementsthatoursolutionshouldsatisfy.ThenwepresentoursolutioninSection4and5.InSection6,weanalyzeitssecurity.Followingthat,theresultsofperformanceexperimentsaregiveninSection7.Finally,weconcludewithashortsummaryandfutureworkinSection8.SecuringtheDistributionsinP2PNetworkswithTrustedPlatformModules27Copyright©2011MECSI.J.ComputerNetworkandInformationSecurity,2011,2,26-33RelatedWork.SecuringP2Pdistributionusingtrustedcomputinghasalreadybeenintroducedby[9]forseveralyears.Andsomeconcreteschemesofdistributionhavebeenproposedbasedondifferentmodelsandassumptions[4,10,11,12].In[10],SandhuandZhangpresentanarchitecturethatprovidesaccesscontrolusingatrustedhardwarecomponentsuchasaTPM,asecurekernel,sealedstorage,andatrustedreferencemonitorthatinteractswithapplicationsthroughsecurechannel.However,thesecuredistributionisjustdescribedinahigh