Overview
Theblockchainconsensusprocessrealizesthedataverificationandaccountingworkofthesharedblockchainledgerbygatheringthecomputingresourcesoflarge-scaleconsensusnodes,soitisessentiallyoneAprocessofcrowdsourcingtasksamongconsensusnodes.Theconsensusnodeinthedecentralizedsystemisself-interested,andmaximizingitsownrevenueisitsfundamentalgoalofparticipatingindataverificationandaccounting.Therefore,itisnecessarytodesignareasonablecrowdsourcingmechanismthatiscompatiblewithincentives,sothattheindividualrationalbehavioroftheconsensusnodetomaximizeitsownbenefitsisconsistentwiththeoverallgoalofensuringthesafetyandeffectivenessofthedecentralizedblockchainsystem.Bydesigningamoderateeconomicincentivemechanismandintegratingwiththeconsensusprocess,theblockchainsystemgatherslarge-scalenodeparticipationandformsastableconsensusonthehistoryoftheblockchain.Thepurposeoftheincentivelayeristoprovidecertainincentivestoencouragenodestoparticipateinthesecurityverificationoftheblockchain.Thesecurityoftheblockchainreliesontheparticipationofmanynodes.Forexample,thesecurityoftheBitcoinblockchainisbasedonthehugeamountofcalculationcausedbytheparticipationofmanynodesintheproofofwork,whichmakesitimpossibleforattackerstoprovideahigheramountofcalculation.Theverificationprocessofanodeusuallyrequiresexpensivecomputingresourcesandelectricalenergy.Inordertoencouragenodestoparticipate,theblockchainusuallyrewardsparticipantsintheformofelectronicmoney.Bitcoin,Litecoin,andEthereumareallproductsofthismechanism.TakeBitcoinasanexample.TheeconomicincentiveintheBitcoinPoWconsensusconsistsoftwoparts:therewardfornewlyissuedBitcoinandthetransactionfeeinthetransactioncirculationprocess.TherewardisgiventotherandomnumberoftheblockthatissuccessfullysearchedduringthePoWconsensusprocessandrecorded.Thenodeoftheblock.Therefore,onlywhenallnodescooperatetobuildasharedandcredibleblockchainhistoryandmaintaintheeffectivenessoftheBitcoinsystem,theBitcoinrewardsandtransactionfeestheyreceivewillbevaluable.Bitcoinhasformedamatureminingecosystem.Alargenumberofminersequippedwithprofessionalminingequipmentactivelyparticipateinthemining-basedPoWconsensusprocess.Thefundamentalpurposeistoachieveprofitbyobtainingbitcoinrewardsandconvertingthemintocorrespondinglegalcurrencies.
Mechanism
Issuancemechanism:Thenumberofbitcoinsissuedineachblockinthebitcoinsystemdecreasesgraduallyovertime.Eachblockfromthegenesisblockwillissue50bitcoinstothebookkeeperoftheblock.Afterthat,thenumberofbitcoinsissuedperblockwillbereducedbyhalfevery4years(210,000blocks).Andsoon,untilthenumberofbitcoinsstabilizesattheupperlimitof21million.AhandlingfeewillbeincurredduringtheBitcointransaction.Thedefaulthandlingfeeisone-tenthofabitcoin,andthispartofthefeewillalsobecreditedtotheblockandrewardedtothebookkeeper.Thesetwopartsofthefeewillbeencapsulatedinthefirsttransactionofeachblock(calledtheCoinbasetransaction).AlthoughthetotaltransactionfeeofeachblockisrelativelysmallcomparedtothenewlyissuedBitcoin(usuallynomorethan1Bitcoin),asthenumberofBitcoinissuancegraduallydecreasesorevenceasestobeissuedinthefuture,thetransactionfeewillgraduallyBecomethemaindrivingforcefornodeconsensusandbookkeeping.Atthesametime,thehandlingfeecanalsopreventalargenumberofmicro-transactionsfromlaunching"dust"attacksontheBitcoinnetwork,andplayaroleinensuringsecurity.
Distributionmechanism:IntheBitcoinsystem,alargenumberofsmallcomputingpowernodesusuallychoosetojointheminingpool,throughmutualcooperationtopoolcomputingpowertoincreasetheprobabilityof"digging"toanewblock,andsharetheblockBitcoinandcommissionrewards.AccordingtoBitcoinmining.Accordingtocomstatistics,13differentallocationmechanismsalreadyexist.MainstreamminingpoolsusuallyadoptmechanismssuchasPPLNS(PayperlastNshares),PPS(Paypershare)andPROP(PROPortionately).Theminingpooldividesthecomputingpowercontributedbyeachnodeintodifferentsharesinproportion,wherethePPLNSmechanismmeansthataftertheblockisdiscovered,eachpartnernodeallocatestheblockaccordingtotheactualshareratiocontributedbythelastNsharesBitcoininChina;PPSdirectlyestimatesandpaysafixedtheoreticalincomeforeachnodebasedontheshareratio.Theminingpoolthatadoptsthismethodwillchargeamoderatefeetomakeupfortheincomeuncertaintyriskitbearsforeachnode;PROPThemechanismallocatesbitcoinsinproportiontothesharescontributedbythenodes.TheemergenceofminingpoolsisapotentialthreattothedecentralizationtrendofBitcoinandblockchain.Howtodesignareasonabledistributionmechanismtoguidenodestocooperatereasonablyandavoidsecurityproblemscausedbyexcessiveconcentrationofcomputingpowerisanurgentneedtosolveresearchproblem.
Blockchaintechnology
Blockchaintechnologyoriginatedin2008byascholarwiththepseudonym"Satoshinakamoto"(Satoshinakamoto)publishedinthecryptographymailinggroup.Thepaper"Bitcoin:APeer-to-PeerElectronicCashSystem"hasnotyetformedanindustry-recognizeddefinitionofblockchain.Inanarrowsense,ablockchainisadecentralizedsharedledgerthatcombinesdatablocksinachainintoaspecificdatastructureinachronologicalorder,andiscryptographicallyguaranteedthatcannotbetamperedwithorforged.,Itcansafelystoresimple,sequentialdatathatcanbeverifiedinthesystem.Inabroadsense,blockchaintechnologyusesanencryptedchainblockstructuretoverifyandstoredata,usesdistributednodeconsensusalgorithmstogenerateandupdatedata,andusesautomatedscriptcodes(smartcontracts)toprogramandmanipulatedata.Decentralizedinfrastructureanddistributedcomputingparadigm.Blockchainhasthecharacteristicsofdecentralization,timeseriesdata,collectivemaintenance,programmable,safeandreliable.Thefirstisdecentralization:theprocessesofverification,accounting,storage,maintenance,andtransmissionofblockchaindataareallbasedonadistributedsystemstructure,usingpuremathematicalmethodsinsteadofcentralinstitutionstoestablishtrustrelationshipsbetweendistributednodes,therebyFormadecentralizedandtrusteddistributedsystem;followedbytimeseriesdata:Blockchainusesachainblockstructurewithtimestamptostoredata,whichaddsatimedimensiontothedata,withverifiabilityandtraceability;Thethirdiscollectivemaintenance:theblockchainsystemusesaspecificeconomicincentivemechanismtoensurethatallnodesinthedistributedsystemcanparticipateintheverificationprocessofdatablocks(suchasthe"mining"processofBitcoin),andpassconsensusalgorithmsToselectspecificnodestoaddnewblockstotheblockchain;thefourthisprogrammable:blockchaintechnologycanprovideaflexiblescriptcodesystemthatsupportsuserstocreateadvancedsmartcontracts,currenciesorotherdecentralizedapplications.