2024年2月8日发(作者：尼康s9600)

刀歌整理　优质项目　币圈交流　微信ｗｗｗ７－７ｗｗｗPlasma:ScalableAutonomousSmartContractsJosephPoonjoseph@kVitalikButerinvitalik@ust11,2017WORKINGDRAFT/AbstractPlasmaisaproposedframeworkforincentivizedandenforcedexecutionofsmartcontractswhichisscalabletoasignificantamountofstateupdatespersecond(poten-tiallybillions)enablingtheblockchaintobeabletorepresentasignificantamountofdecentralizedfimartcontractsareincentivizedtocontinueoperationautonomouslyvianetworktransactionfees,whichisultimatelyreliantupontheunderlyingblockchain(um)oseamethodfordecentralizedautonomousapplicationstoscaletoprocessnotonlyfinancialactivity,butalsoconstructeconomicincentivesforgloballypersistentdataservices,iscomposedoftwokeypartsofthedesign:Reframingallblockchaincompu-tationintoasetofMapReducefunctions,andanoptionalmethodtodoProof-of-Staketokenbondingontopofexistingblockchainswiththeunderstandnstructionisachievedbycomposingsmartcontractsonthemainblockchainusingfraoseblockchainsintoatreehierarchy,andtreateachasanindividualbranchblockchainwithenforcedblockingone’sledgerentryintoachildblockchainwhichisenforcedbytheparentchain,onecanenableincrediblescalewithminimizedtrust(presumingrootblockchainavailabilityandcorrectness).Thegreatestcomplexityaroundglobalenforcementofnon-globaldatarevolvesarounddataavailabilityandblockwithholdingattacks,Plasmahasmitigationsforthisissuebyallowingforexitingfaultychainswhilealsocreatingmmerkleizedcommitmentsarebroadcastperiodicallytotherootblockchain(um)duringnon-faultystates,thiscanallowforincrediblyscalable,enablespersistentlyoperatingdecentralizedapplicationsathighscale.1

刀歌整理　优质项目　币圈交流　微信ｗｗｗ７－７ｗｗｗ1ScalableMulti-PartyComputationWithblockchains,thesolutionforenforcingcorrectnesshptffortstoscaleblockchaintransactionalcapacity(ingNetwork[1])requiresusingtimecommitmentstobuildafidelitybond,(anassert/challengeagreement)sothattheasserteddatamustbesubjectsert/challengeconstructionallowsonetoassertaparticularstateiscorrect,andifthevalueisincorrect,thenadisputeperiodexistswhereanotherobservercventoffraudulentorfaultybehavior,eatesamechanismforparticipantstngthisassert/challenge-proofconstruction,interestedparticipantscanbeabletoassertgroundtruthstonon-interestedparticipantsontherootblockchain(um[2][3]).Thisstructurecanbeusednotonlyforpayments,butextendedtocomputar,thepresumptiotningNetwork,forexample,theconstructionmakesitsothatonecanestablishcommitmentstocomputingcontractstate(e-signedtreeofmultisignaturetransactionsofconditionalstate).Theseconstructionsallowforhighlypowerfulcomputationatscale,howevertherearesomeissueswhichrequirethesummationofalotofexternalstate(ionofentiresystems/markets,computationofalargeamountofshared/incompletedata,largenumberofcontributors).Thisformofcommitmenttomultipartyoff-chainstate(”statechannels”[4])requiresparticipantstofullyvalidatethecomputation,orelsetherearesig-nificantamountoftrustestablishedinthecomputationitself,onally,thereisusuallyapresumptionof”rounds”wherebytheexecutionpathmustbecompletelyunrolledbeforecontractinitiation,whichgivesparticipantstheopportunitytoexitandforceexpensivecomputationon-chain(asitisnotpossibletoprovewhichpartyishalting).Instead,weseektodesignasystemwherebycomputationcanoccuroff-blockchainbutultimatelyenforcibleon-chainwhichisscaltateupdatesoccuracrossanautonomoussetofproof-of-stakevalidatorswhoareincentivizedtowardscorrectbehaviorenforcedbyfraudproofs,whichallowforcomputationtooccedstobeabletominimizeissuesaroundthedataavailabilityproblem(ithholding),minimizingthestateupdatesintherootblockchainnecessaryintheeventofbyzantineactorstopreventrisk-discountedtransactionfeesontherootchain,rtotheLightningNetwork,Plasmaisaseriesofcontractswhichrunsontopofanexistingblockchaintoensureenforcementwhileensuringthatoneisabletoholdfunds2

刀歌整理　优质项目　币圈交流　微信ｗｗｗ７－７ｗｗｗinacontractstatewithnetsettlement/withdrawalatalaterdate.2PlasmaPlasmaisawaytodoscalablecomputationontheblockchainwiththestructureofcreatingeconomicincentivestoautonomouslyandpersistentlyoperatetheonally,significantscalabilityisachievedbyminimizingthefundsrepresentedinaspendfromacontracttoasinglebitinabitmap,sothatonetransactinethiswithaMapReduce[5]frameworktobeanstructionallowsonetobeabletohaveexternalizedpartiesholdfundsandcomputecontractsonone’sbehalfsimilartoaminer,butPlasmainsteadrunsontopofanexistingblockchainsothatonedoesnotneedtocreatetransactionsontheunderlyingchainforeverystateupdate(includingaddingnewusers’ledgerentries),1:AnyonecancreateacustomPlasmachainforsmartcontractscalabilityformanydiffisaseriesofstchainistheenforcerofallcomputationglobally,asmablockreum,PlasmawouldbecomposedofEVMsmartcontractsrunningdirectlyonEthereum,butonlyprocessingtinycommitmentswhichcanrepresentanincrediblylargeamountofcomputationandfiiscomposedoffivekeycomponents:Anincentivelayerforpersistentlycomput-ingcontractsinaneconomicallyefficientmanner,structureforarrangingchildchainsinatreeformattomaximizelow-costefficiencyandnet-settlementoftransactions,aMapRe-ducecomputingframeworkforconstructingfraudproofsofstatetransitionswithinthesenestedchainstobecompatiblewiththetreestructurewhilereframingthestatetransitionstobehighlyscalable,aconsensusmechanismwhichisdependentupontherootblockchainwhichattemptstoreplicatetheresultsoftheNakamoto[6]consensusincentives,andabitmap-UTXOcommitmentstructureforensuringaccuratestatetransitionsofftheroot3

刀歌整理　优质项目　币圈交流　微信ｗｗｗ７－７ｗｗｗngforexitsindataunavailabilityorotherByzantinebehaviorisoneofthekeydesignpointsinPlasma’soperation.2.1ThePlasmaBlockchain,orExternalizedMultipartyChannelsWeproposeamethodwherebymultipartyoff-dsheldinthePlasmachain,thisallowsfordepositandwithdrawaloffundsintothePlasmachain,lowsforenforciblestateandfungibilitysinceoneisabletodepositandwithdraw,withaccountingofthePlasmablockmatchingthefundsheldintherootchain(Plasmaisnotdesignedtobecompatiblewithfractionalreservebankingdesigns).Figure2:smablockchaindoesnotdisclosethecontentsoftheblockchainontherootchain(um).Instead,blockheaderhashesaresubmittedontherootchainandifthereisproofoffraudsubmittedontherootchain,veryefficient,asmanystateupdatesarerepresentedbyasinglehash(plussomesmallassociateddata).Thisupdatecanrepresentbalanceswhicharenotrepresentedontherootblockchain(Alicedoesnothaveherledgerbalanceontherootchain,herledgerisonthePlasmachain,andthebalanceintherootchainisrepresentingasmartcontractenforcingthePlasmachainitself).Grayitemsareoldblocks,blackisthiblyhighamountoftransactionscanbecoticipantcantransferfundstoanyone,inransferscanpayintoandwithdraw(withsometimedelayandproofs)fundsintherootblockchain’snativecoin(s)/token(s).Plasmaallowsone(oranetworkofparticipantsinaproof-of-stakenetwork)tobeabletomanageablockchainwithoutafullpersistentrecordoftheledgerontherootblockchain4

刀歌整理　优质项目　币圈交流　微信ｗｗｗ７－７ｗｗｗorstcase,ftructaseriesoffraudproofsassmartcontracts[7]ontherootblockchainwhichenforcestateinthisrtotheLightningNetwork,whenwithdrawingfunds,tructaninteractivegamewherebytheexitingpartyatteststoabitmapofparticipants’onthenetworkcansubmitanalternate*bonded*ventthisisincorrect,anyoneonthenetworkcanattufficienttime,thesecond*bonded*roundallowsforthewithdrawaltooccur,whichisabondonstate*before*lowsdinatedmasswithdrawalevents,aparticipantmaybeabletoexitwithlessthan2-bitsofblockspaceconsumedontheparentblockchain(hereumon-chaininworstcasescenarios).Intheeventofablockwithholdingattack,participantscanrapidlyandcheaplydoamass-exit,withsubstantialcostsavingsversusotherpreviousoff-on-ally,thisdoesnotplaceanytrustinacoalitionofvalidatornodes(SidechainFunctionaries,Fishermen).Figure3:block(Block#4)isablockwhichiswithheldandcommittedontherootchain,butAliceisnotabletoretrievePlasmablock#tsbybroadcastingaproofoffundsontherootblortohowclosingoutLightningisaninteractivemechanismbetweentwopartici-pantstoenableenforcibleinfinitepaymentsbetweenthemselves,thisallowsforaninterac-5

刀歌整理　优质项目　币圈交流　微信ｗｗｗ７－７ｗｗｗmarydifferenceisthatnotallparticipantsneedtobeonlinetoupdatestate,andtheparticipantsdonotneedarecordofentryontherootblockchaintoenabletheirparticipation–onecanplacefundsonPlasmawithoutdirectinteractionon-chain,withminimaldatatoconfirmtransactionswhenconstructingthesePlasmachainsinatreeformat.2.2EnforcibleBlockchainsinBlockchainsFigure4:ommitmentsflowdownandexitscanbesubmittedtoanyparentchain,tningNetworkusesanadjudicationlayerforpaymentswhichisultimatelyenforcibleontherootblockchain,wecreateasystemofhigherandlowercoinisByzantine,ithastheoptionofgoingtoanyofitsparents(includingtherootblockchain)dofenforcementofanincrementingnoncestate(viarevocations),weconstructasystemoffraudprffect,weareabletocreatestatetransitionswhichareonlyperiodicallycommitted6

刀歌整理　优质项目　币圈交流　微信ｗｗｗ７－７ｗｗｗtoparentchains(whichthenflowstotherootblockchain).Thisallowsforincrediblescaleofcomputationandaccountstate,asweareabletoonlysubmitrawdatatoparent(orroot)ryfrompartiallyByzantineconditionsaildblockchainrunsontopofarootblockchain(um)andfromtherootblockchain’sperspective,isonlyseeingperiodiccommitmentswiththetokensbondedinthecontractforenforcementossignificantadvantagesinmaximizingblockavailabilityandminimizingstakeforvalidationofone’r,sincenotalldataisbeingpropagatedtoallparties(onlythosewhowishtovalidateaparticularstate),partiesareresponsibleformonitoringtheparticularchaintheyareinterestedinperiodicallytopenalizefraud,aswellaspers5:Thefaultyblockchain(shadedinred)isroutedaroundbybroadcastingacommitmenttoitsparentPlasma/rootchain(rightdottedblueline).Participantsinthe3rddepthPlasmachaindoamassmigrationtoanotherchaintogether(leftbluedottedline)nstruction,innon-Byzantineenvironments,resetofupdatesacrossallchainscanbeattestedtoina32-bytehashwithasignature.7

刀歌整理　优质项目　币圈交流　微信ｗｗｗ７－７ｗｗｗ2.3PlasmaProof-of-StakeWhileit’sfairlyinterestingtobeabletoholdfundonbehalfofotherswithasinglevalidator,weproposeamethodwherebyasinglepartycanenforcestatewithasetofvalidators,ofteninaproof-of-stakeframeworkrequiringeitherETHbonding,orbondinginatoken(-20).Theconsensusmechanismforthisproofofstakesystem,isagain,mpttoreplicatetheincentivesaroundtheNakamotoConsensus,evethatoneofthemoreusefulincentivemechanismsconstructedasaresultoftheNakamotomechanismissareprobabilisticallyknownovertime(intheoriginalimplementationitwas6confirmations).Whenonefindsablock,oneisfairlysuretheyarelikelytheleader,rethattheyaretheleader,theypropaevethisisasignificantifnotthekeycontrib-of-stakecoalitionsfacethisissuesinceit’spossibleifonedoesstraightleaderelec-tion,blockwithholdingattacksbymajoritycartels(alsogeneralizedasthe”dataavailabilityproblem”)becomemagnifiitigatethisinPlasmaProof-of-Stakebyallowingstakeholderstopublishontherootblockchanbuilduponblocksinparallel(toencouragemaximuminformationsharing).Wecreateincentivesforvalidatorstorepresentthepast100blockstomatchthecurrentstakerratio(takes3percentofthecoins,theyshouldbe3percentofthepast100blocks),byfees(duetosuboptimalbehaviorbystakers)tmentexistsineveryblockwhichincludesdatafromthepast100blocks(withanonce).periodoftime,theblocksarefinalized.8