外文翻译NET Compact Framework嵌入式系统中的随机控制协议CRP.docx
- 文档编号:29596160
- 上传时间:2023-07-25
- 格式:DOCX
- 页数:19
- 大小:176.54KB
外文翻译NET Compact Framework嵌入式系统中的随机控制协议CRP.docx
《外文翻译NET Compact Framework嵌入式系统中的随机控制协议CRP.docx》由会员分享,可在线阅读,更多相关《外文翻译NET Compact Framework嵌入式系统中的随机控制协议CRP.docx(19页珍藏版)》请在冰豆网上搜索。
外文翻译NETCompactFramework嵌入式系统中的随机控制协议CRP
翻译部分
英文原文
PerformanceoftheControlledRandomnessProtocolon.NETCompactFrameworkEmbeddedSystems
Abstract—TheControlledRandomnessProtocol(CRP)formanagementofcryptographickeysisamethodtoimprovethesecuritylevelofsecurecommunicationprotocols.WeassesstheperformanceoftheCRPwhenimplementedonembeddedsystemsrunningthe.NETCompactFramework.Wepresentourfindingsfromtwodifferentplatforms:
onesmartphonerunning.NETCompactFramework3.5andonesmartphonerunning.NETCompactFramework4.0.Ourassessmentverifiesthatwhenimplementedinthe.NETCompactFramework,thecontrolledrandomnessprotocolimposesaconfigurableandtolerableamountofoverheadcomputationwhileitoffersasignificantsecurityimprovementcomparedtoaconventionalimplementationofakeymanagementprotocol.
I.INTRODUCTION
Inrealworldapplicationsofcryptographicprotocols,thekeymanagementproblemreferstothelifecyclemanagementofcryptographickeys.Itincludesthenecessaryoperationsforkeygeneration;distribution;storage;replacementandexchange;usage;anddestruction[1].Inordertoretainaspecificsecuritylevel,keysusedincryptographicalgorithmsandprotocolsmustbeperiodicallyrefreshedi.e.,newkeysareexchangedbetweencommunicatingpartiesandoldkeysarereplaced.Theseprecautionsensurethatonlyaspecificamountofinformationisencryptedunderthesamekeyandthus,theexposureofinformationisminimizedincaseakeyisleaked.
Keyagreementistheprocessbywhichtwoormorepartiesagreeonacommoncryptographickeyforaspecifictimeframe.Keytransportistheprocessbywhichtheagreedkeyistransferredtotheparticipants.Inmanyscenarios,thetwoprocessesoccursimultaneously:
theparticipantsexchangeinformationbywhichtheybothsetandexchangethekey(s)tobeused(orsomepartsofit).Inmanyscenarios,thekeyagreementandtransportoccurasexchangeofcontrolmessagesthroughacontrolchannel.Thischanneldoesnotinterferewiththedatachannelinwhereactualsecuredataexchangetakesplace.Apublic-keycryptosystem(PKC)iscommonlyusedinsuchsetupsinordertosecurelyexchangethroughthecontrolchannelthesymmetric-keycryptosystem(SKC)encryption/decryptionkeysusedtosecurelyexchangedatawithinthedatachannel.Thelatterkeysareoftencalledephemeralorsessionkeys,sincetheirlifetimespansaspecifictimeperiodi.e.,asessionandthentheyaredisposed.
Intypicalresource-limitedenvironment,liketheembeddedsystemsare,itisrathercostlytoimplementanduseapublickeycryptography(PKC)schemeforsecurecommunicationbetweentwoentities.Whentheresourceconstraintsaremoresevereortheparticipantsareallknownbeforehand,anotheroptionistoreplacethe“heavy”PKCschemeinthecontrolchannelwithalighterSKCscheme.TheSKCschemecanuseamasterkeyinordertosetandtransfertheephemeralkeysneededforthedatachannel.Inthesecasesandforsakeofresourceeconomy,thesameSKCalgorithmcanbeusedinboththe“control”and“data”channelsalbeitwithdifferentkeys.
Anembeddedsystemcanincuraninterestingtradeoffonsecuritylevelandresourceconsumption.Fromasecuritypointofview,thekeysmustbeoftenrefreshed,asexplainedearlier,inordertomaintaintherequiredsecuritylevel.Fromasystemresourceconsumptionpointofview,thekeysmustberarelychanged,inordertominimizetheconsumptionofpreciousresources(processor,power,bandwidth).Further,insomeusagescenarios,advancedcaremustbetakeninordertoensurethatthenewkeyswillbeavailablebythetimetheymustbeused,especiallywhenonlyintermittentconnectivityexists.
The“controlledrandomnessprotocol”(CRP)forcryptographickeymanagementwasproposedasanimprovementforthesecuritylevelofsecurecommunicationprotocols[2].TheCRPallowsmultiplekeystobevalidatanygiventime;itneitheraltersthetotalnumberofkeysneededintheunderlyingcryptographicalgorithms,northeneedofacontrolchanneltoperiodicallyrefreshkeys.However,theincreasedsecurityofferedbyCRPallowsforfarlessfrequentkeyexchanges.TheMicrosoft.NETCompactFramework(.NETCF)isasoftwareframeworkdesignedtorunonmobileandembeddeddevicesthatarebasedontheMicrosoftWindowsCEplatform.Exampledevicesincludesmartphones,PDAs,andfactorycontrollers.The.NETCFusesasubsetofthelibrariesavailableinthefull.NETFramework.Italsoincludessomeadditional,mobiledevice-specificlibraries.The.NETCFlibrariesareinfactstripped-downversionsofthefull.NETFrameworklibrariesastominimizetheirfootprintandfitintheresourcelimitedenvironmentofthemobileandembeddeddevices.
InthispaperweassesstheperformanceoftheControlledRandomnessProtocolwhenimplementedonembeddedsystemsrunning.NETCF.Wepresentourfindingsfromtwodifferentembeddedplatforms:
onesmartphonerunningMicrosoftWindowsMobile6.5with.NETCF3.5andonesmartphonerunningMicrosoftWindowsPhone7with.NETCF4.0.Wealsoverifyourfindingsonacommoditydesktopcomputerthatsupportsthefull.NETFramework3.5.Theperformancereportedinthelatterenvironmentisnotconsistentwithourfindingsfortheembeddedplatforms.Weprovideinsightsandpossibleexplanations.
Therestofthepaperisorganizedasfollows.SectionIIpresentsthekeymanagementproblemandthecontrolledrandomnessprotocol.SectionIIIpresentsourtestbedenvironmentandexperimentsheld.SectionIVpresentstheresultsofourexperimentsanddiscussesourfindings.Finally,SectionVconcludesourfindingsanddiscussesfuturedirectionsofthework.
II.THECONTROLLEDRANDOMNESSPROTOCOL
Conventionalcryptographicschemesoperateundertheassumptionthatatmostonekeyisactiveinanytimemoment.Thereisonlyoneexceptiontothisassumption.Thisisthethetransitionperiodswhenchangingacryptographickey.Inthesecases,atmosttwokeyscanbeactiveinordertocopewithdelayedmessages.Twooftheauthorsofthispaperproposedanovelapproachofhavingmorethanonekeyatanygiventimemoment[2].Theapproachisbasedontheconceptof“controlledrandomness”i.e.,randomlyusingkeysinacontrolledenvironment.Theconceptof“controlledrandomness”canbeutilizedinanyprotocolthatusestemporal(ephemeral)keys.Itincreasesprotocolsecuritywithminimalcomputationaloverhead.Forsakeofcompleteness,wedescribeinthefollowingparagraphstheControlledRandomnessProtocol(CRP).
A.ProtocolDefinition
Assumeatimeperiodt=[0,T]composedoftimeslotst1,t2,...,tnsuchast=t1∪t2∪...∪tn.Eachtimeslottirepresentsasession.Withineachsessiononespecific,temporalcryptographickeykiisusedinconventionalschemes.TheControlledRandomnessProtocolworksasfollows.Withinthetimeperiodteverycryptographickeyk1,k2,...,knisvalidandcanbeused.Thesenderchooseswithauniformdistributionarandomintegeriandencryptstheinputdatausingthekeyki.Thereceiverhasaccesstoasecretmechanismanduponreceivingaciphertextcicandeducewhichofthepossiblekeyswasusedfortheencryption
andthus,usethecorrectonetodecrypttheciphertext.TheCRPdoesnotdictatehowallthesekeysaretransferredtothereceiver.ItcanbethroughacontrolchannelusingaPKCscheme,oranSKCwithmasterkey,oranyothermethod.TheCRPdictateshowallthesekeysareusedandreusedwithinatimeframecomposedofmanyconventionalsessions.
Twodifferentmethodsareoriginallyproposedin[2]forderivingtheindex,j,ofthesecretkeyusedforagivenciphertext.Thefirstmethodisusingasynchronizedrandomnumbergenerator(RNG)inboththesenderandthereceiverfortheindexes.
ThesecondmethodinvolvesusageofaKeyedHashFunction(KHF)alsoknownasMessageAuthenticationCode(MAC).ThesenderandthereceiveragreeonasetofnencryptionkeysforachosenencryptionalgorithmasusualandadditionallyonasetofnkeysforcomputingMAC.ThesenderfurtherusesanRNG.Inthiscases,thesenderworksasfollowsforeveryplaintextm:
1)Senderchoosesarandomnumberj.
2)SenderencryptsmunderkeykjtoproducetheciphertextE(m,kj).
3)SendercomputesH(E(m,kj),hj)i.e.,theMACoftheciphertextusingthej-thMACkey.
4)SendersendsE(m,kj)||H(E(m,kj),hj),where||denotestheconcatenationoperation.
ThereceiverworksasfollowstorecovermfromthequantityE(m,kj)||H(E(m,kj),hj):
1)ReceivercomputesH(E(m,kj),hj)foreverypossiblej=1,2,...,n.ThisstepinvolvesatmostnMACoperations.Uponcompletingallcomputations,thereceiverhasderivedthesecretindexjusedbythesender.
2)ReceiverdecryptsE(m,kj)usingthej-thdecryptionkey.Thisstepinvolvesonedecryptionoperationandderivestheplaintextm.
B.AdvantagesofCRP
Theconceptofcontrolledrandomnessi.e.,havingmultipleactivekeysatanygiventimemoment,offerssuperiorsecuritycharacteristicscomparedtoconventionalprotocols.Thesystemdesignercanreusewell-knowncryptographicblocksinannovelwaytoachieveincreasedsecuritywithminimalhassle:
•minimalcomputationaleffortcanbeinducedbyCRPinthecasethatbothsenderandreceivercanmaintainasynchronizedrandomnumbergenerator.
•thesynchronizationrequirementcanberelaxed,ifthesystemcansustainsomeincreasedcomputationaleffortinducedbytheKHF(MAC)operations.
•inheavilyconstrainedenvironments,thetwoabovemechanismscanbereplacedbysendingtherandomnumberjwitheachpacket.Inthiscase,somesecurityisindeedsacrificedsinceanattackercanknowwhichpac
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 外文翻译NET Compact Framework嵌入式系统中的随机控制协议CRP 外文 翻译 NET Framework 嵌入式 系统 中的 随机 控制 协议 CRP