区块链技术发展现状与展望

424Vol.42,No.420164ACTAAUTOMATICASINICAApril,20161;21;3,.,.,,,,,.,,,,,..,2016,42(4):481¡494DOI10.16383/j.aas.2016.c160158Blockchain:TheStateoftheArtandFutureTrendsYUANYong1;2WANGFei-Yue1;3AbstractBlockchainisanemergingdecentralizedarchitectureanddistributedcomputingparadigmunderlyingBitcoinandothercryptocurrencies,andhasrecentlyattractedintensiveattentionfromgovernments,¯nancialinstitutions,high-techenterprises,andthecapitalmarkets.Blockchain0skeyadvantagesincludedecentralization,time-seriesdata,collectivemaintenance,programmabilityandsecurity,andthusisparticularlysuitableforconstructingaprogrammablemonetarysystem,¯nancialsystem,andeventhemacroscopicsocietalsystem.Inthispaper,weproposedabasicmodeloftheblockchainsystem,discussedtheprinciples,technologies,methodsandapplicationsofblockchainandtherelatedBitcoinsystems.Wealsodiscussedthesmartcontractanditsapplications,andpresentedthefuturetrendsofblockchain-enabledparalleledsocieties.Thispaperisaimedatprovidinghelpfulguidanceandreferenceforfutureresearche®orts.KeywordsBlockchain,Bitcoin,consensusmechanism,smartcontract,paralleledsocietyCitationYuanYong,WangFei-Yue.Blockchain:thestateoftheartandfuturetrends.ActaAutomaticaSinica,2016,42(4):481¡494.,,,.,2016-02-222016-03-02ManuscriptreceivedFebruary22,2016;acceptedMarch2,2016(71472174,71102117,61533019,71232006,61233001)SupportedbyNationalNaturalScienceFoundationofChina(71472174,71102117,61533019,71232006,61233001)RecommendedbyAssociateEditorLINZong-Li1.1001902.2661093.4100731.TheStateKeyLaboratoryofManagementandControlforComplexSystems,InstituteofAutomation,ChineseAcademyofSciences,Beijing1001902.QingdaoAcademyofIntelli-gentIndustries,Qingdao2661093.ResearchCenterofMili-taryComputationalExperimentsandParallelSystem,NationalUniversityofDefenseTechnology,Changsha410073,/,[1].,,..20161,[2],;,.201512Linq,;,.2016,1048242.R3CEVAzureBaaS(Blockchainasaservice,),40,.2008\(Satoshinakamoto):[3],.,,(Decentral-izedsharedledger),.()..:,,;:,,;:(\),;:,.,(Ethereum)[4];:,,.,.,1.02.03.0[1].,2.0,P2P.,,1.0,.,,.20162,WebofScienceEIVillage,\/blockchain2[5¡6]9[6¡14].,.:1;2;34;5;6;7.1.Blockchain.info,7500120000,40[15].coinmarketcap.com,20162,675,67,86%,[16].()1500,389.5059,2015GDP144().,,.2027,10%GDP[17].()200914,.,10,;20105,125,.,,2013111242,1241.98.CoinDesk,6,4:483[18].,,(Proofofwork,PoW).PoW(,),,.,..,().,,.,[19].\,\.,(),;().,,.,,[20].,.(),,.,(1),.;(),PoW().,,.,(),;,.,.\,.,,.1Fig.1TheBitcoinecosystem48442,,.,.2,,.,.2.,.,;;;,;,;.,.2.1.Merkle,,,.Merkle.:3,(Header)(Body).(Version)(Prev-block)(Bits)PoW(Nonce)Merkle(Merkle-root)(Timestamp)[21].PoW,Nonce..MerkleMerkle.2Fig.2Abasicframeworkofblockchain3Fig.3Thestructureofblocks:,.,,,,.,\,\,4:485.,,,,,[19].:,.,.,.(Proofofexistence),,.,,.:,,.(),.,(),()(),().SHA256,SHA256256(32).,SHA256(2256)(),.Merkle:Merkle,.3,Merkle(),(Merkle).Merkle,Merkle,Merkle.MerkleMerkle,[22],Merklepatriciatree[4].Merkle:,,;Merkle\,,()[3].,36,6Merkle(6,5,56,78,5678,1234).,Nlog2N.,.:,RSAElgamalRabinD-HECC().,.,(),;,.,(A)(B)B,B.;AB,BAA;,.,4:256.2256,,.,256SHA256Base58,50;Secp256k165.,SHA256RIPEMD16020(hash160),SHA256Base5833[19].,.486424Fig.4TheasymmetriccryptographyoftheBitcoinsystem,..,,.2.2.,,,,.:,(Peer-to-peernetwork,P2P).P2P,,.,.,.,;,20162,60GB.,,2.1.:,.,\[4].,[3]:1);2);3);4),;5),;6),,.,,\,.,,,.[19].:P2P.,.,,;,,.,P2P,,,;,4:487\,,;,,.,.,,,.,,\;\,.2.3.\\,;,..(Proofofwork,PoW).,,(Proofofstake,PoS)[23](Delegatedproofofstake,DPOS)[24]..PoW:PoW,.,()SHA256(),.:,(Nonce)3SHA256.10.,PoW(3)[19]:1.,Coinbase,;2.Merkle,,Nonce;3.Nonce1;SHA256,,;3;4.,Merkle.,,,\.Blockchain.info,20162,17,398346\0000000000000000077f754f22f21629a7975cf¢¢¢.,16,171617.,PoW,SHA256,,.,20161,800000000Gh/s,8£1018,Top500.PoW,,;PoW,(),10.PoS:PoSPoW.,PoSPoW.PoSPoW,.,(Coindays).,48842.,1010,100;5,50.,PoS,,PoS.,PoW,PoS,.PoW,,.,PoS,PoW,,PoS.DPoS:DPoS\,,101\,().,.\,,100.,,\.,99%[24].,PoWPoS,DPoS,,.,PoW+PoS(Proofofac-tivity).,PoW,,PoSDPoS,.2.4,.,.,,.,.,PoW,PoW.,,.,PoW,.:.50,4(21),,2100[19].,,.(Coinbase).(1),,.,\,.:,,\,.Bitcoinmining.com,13[25].PPLNS(PayperlastNshares)PPS(Paypershare)PROP(PROPortionately).(Share),PPLNS,N;PPS,4:489;PROP.,.2.5.\,,.,;,,.,;5.,.,,.,\,;,.,,P2PKH(Paytopublickeyhash),[19]..,(),;,;,;NM,M¡N,NM..,.,,,,.,,.,,[4].3,,,.,,.:(),.,Merkle,.,53.,(),()[7].:,.,,.;Factom49042[26].:.,,\,;,P2P;,,,,,;,SWIFT;R3CEV.:,.,,;,,\,.,,,Airbnb;,.:.,;,.,,[27];,\.,,(Publicblockchain)(Consortiumblockchain)(Privateblockchain).,,PoWPoS..(),,,105;,,,.,,2,.4,..4.1.,PoW51%,51%.,60%,51%,[1].51%,51%.PoS51%,N@S(Nothingatstake).PoW51%[4],..,,SHA256248,,,..,().,,,4:491.4.2.:,.,60GB,,[28].:7,(VISA10000)[1];:10,10,.4.3PoW,SHA256,,\,.,,,.,,.,Primecoin()()SHA256[29].,.4.4,,.,.,(Blockwithholdingattacks),.,.,\[30].,.,,,,,,.51994NickSz-abo,,,.,..(),,,,.,,.,.,|,.,,.,,,..5:,,(),P2P.().,.492425Fig.5Therationaleofsmartcontracts.,P2P.P2P,.,.,,.,,,(),..,;,;,[1]..,,,2.03.0;,,,,(Decentralizedapplica-tion,Dapp)(Decentralizedau-tonomousorganization,DAO)(Decentralizedautonomouscorporation,DAC)(Decentralizedautonomoussociety,DAS).,.\IF-THEN,.\WHAT-IF,\\[31¡32].6,,{,\+4.0.+CPS(Cyber-physicalsystems,CP