DecentralisedCompu7ng Trustinatrustlessworld? AndreaBracciali abb@cs.s7r.ac.uk Distributed*Ledger*Technology*Workshop Perugia,*1*2*2018*
Decentralisa7on:interes7ngnewidea ImplementedinBlockchaintechnologies technical,social,economical, andpoli7calaspects) Someopenques7onsdeserveresearch
Bitcoin:acurrencywithoutacentral)bank Afootballmatchwithoutareferee? Decentralisedtrustimplementedbyadistributedconsensusmechanism proof*of*work)andvalidatedbycomputa7on: EXAMPLEPICTURETRANSACTION DUP HASH160 PUSHDATA20)[3eae3697975ae35c475e52307f26b8db0d554dcb] EQUALVERIFY CHECKSIG DUP HASH160 PUSHDATA20)[b08f46e4d21cd0547a8a1e2e43e5440284f710a4] EQUALVERIFY CHECKSIG TECHNICALLEGALSOCIAL
Bitcoin:acurrencywithoutacentral)bank Afootballmatchwithoutareferee? But* [whatincaseofathe\? Astolenpassword [whatisathe\? A stealingtransac7on isindis7nguishablefromagenuineone [whichpolice? Noauthority,norecovery,back[ups,back[tracks [whoisthethief? Nopeople,noiden77es TECHNICALLEGALSOCIAL
Bitcoin:acurrencywithoutacentral)bank Afootballmatchwithoutareferee? Decentralisedtrustrelyingon 1.acomplexandsensi7vecrypto@economics*framework,e.g., When cryptocurrencies mine their own business? Jason Teutsch, Sanjay Jain, and Prateek Saxena whichmodels? Ra7onalagents,stochas7cbehaviour,preferences Socio[economic CRYPTO[ECONOMICSTECHNICALECONOMICALSOCIAL
Bitcoin:acurrencywithoutacentral)bank Afootballmatchwithoutareferee? Decentralisedtrustrelyingon 2.suitabledesignofmonetarypolicy, e.g.21mbtclimit,defla7onary? 22,500 20,000 non[adap7vesofar),storeofvalue,newgold. 15,000 3.supportbyfiatcurrencies,measureofvaluesofar). 12,500 USD 17,500 10,000 7,500 2017/10/17 02:00 USD: 5,604 5,000 2,500 Feb '17 Mar '17 Apr '17 May '17 Jun '17 Jul '17 Aug '17 Sep '17 Oct '17 Nov '17 Dec '17 Jan '18 Feb '18 CRYPTO[ECONOMICSTECHNICALECONOMICALSOCIAL
Reallydecentralisedgovernance? 50% Fourgroups [ CRYPTO[ECONOMICSGOVERNANCESOCIALPOLITICAL
Decentralisedgovernance:disputesandforks Scalability #transac7ons 5[20 vs 2000VISA) Recentdispute 2017) off[chaintransac7ons vs largerblocks sidechains) Ascalableverificationsolutionforblockchains Jason Teutsch TrueBit Establishment jt@truebit.io Christian Reitwießner Ethereum Foundation chris@ethereum.org EndedupinasplitofthecommunityandofthecurrencyBCH * Wasalsoaproblemofgovernance:largerblocks,largercomputers,less decentralisa7onbut seepreviousslide). GOVERNANCETECHNICALECONOMICALSOCIAL
Decentralisedgovernanceandexternalcontrol Patrollingtheborders: [exchanges e.g.recentcorrela7onsouthkoreapresumednormingvsbtcvola7lity) Decentralisa7onfadesawaywhencrossingvirtualandrealboundaries, [exchanges [regulatorybodiesussecandlocalgovs,ukfca, ) [taxes [trackingiden77esiwannacry,pseudo[anonymity) [Monero,zero[knowledgeprotocols,homomorphicencryp7on LEGALECONOMICALSOCIAL
dappi:bithalobay):decentralisedebay trustinescrows) Twountrus7ngpartnerssaveadepositinanescrow. Thesmartcontractreturnsthedeposit,ifbotharehappy aboutagiventransac7on. Nocentralauthorityinterven7onorprevioustrustbetweenpar7es. Whichmodels? LEGALECONOMICALSOCIAL
6 6 o / V V dappi:bithalobay):decentralisedebay trustinescrows)! GAMETHEORY:exploringanddefiningstrategies! FORMALMETHODS:automatedquan7ta7veanalysisofa probabilis7cmodel! QUANTITATIVECHARACTERISATIONOFTHEPROTOCOL SFEATURES ship ship deposit start /?>=< 89:; 0 reset) 89:;?>=< 1 ED ED ED KO ko 89:;?>=< P :0.15 2 B 89:;?>=< 5 KO EDC ok P :0.85 wpppppp ship 89:;?>=< 3 0:0.05 B BC 89:;?>=< 4 /?>=< 89:; 6 1:0.95 ED@ABC pay OK Fig. 1. The graph of the transaction protocol. ship a) Buyer s automata TECHNICALCRYPTO[ECONOMICS
dappi:bithalobay):decentralisedebay trustinescrows) Validation of Decentralised Smart Contracts Through Game Theory and Formal Methods Giancarlo Bigi 1,AndreaBracciali 2B),GiovanniMeacci 3,4, and Emilio Tuosto 5 TECHNICALCRYPTO[ECONOMICS
dappii:decentralisedquality)informa7on empoweringci7zens data*ownership* *GDPR,*H2020,* ) LEGALECONOMICALSOCIALPOLITICAL
dappiii:lendingcrypto[currenciesina decentralisedworld Difficult!notthereyet) 1. Vola7lity 2. Counter[partyrisk Shouldbemanagedbycode! Proposedsolu7onsinchtowardscentralisa7on,e.g.for1.: linkingthedebttoafiatcurrency: Iwillreturntheequivalentof100USDinBTC. Whodoesprovidetheexactamount? LEGALECONOMICALSOCIALPOLITICAL
Relaxingdecentralisa7on backtobusinessasusual?) Fromnon[permissionedtopermissionedanddouble[permissioned) blockchains,e.g. [HyperledgerIBM++) [Stellar The Stellar Consensus Protocol: A Federated Model for Internet-level Consensus DAVID MAZIÈRES, Stellar Development Foundation Qv 7 ) = {{v 7 }} Qv 1 ) = Qv 2 ) = Qv 3 ) = {{v 1, v 2, v 3, v 7 }} v 3 v 5 v 2 v 1 v 7 v 4 v 6 Qv 4 ) = Qv 5 ) = Qv 6 ) = {{v 4, v 5, v 6, v 7 }} Fig. 7. Ill-behaved node v 7 can undermine quorum intersection. LEGALTECHNICALSOCIAL
Ethereum:theconsensuscomputer Decentralisedcomputa7on: [stateandcomputa7onentertheblockchain, ETHEREUM: A SECURE DECENTRALISED GENERALISED TRANSACTION LEDGER EIP-150 REVISION DR. GAVIN WOOD FOUNDER, ETHEREUM & ETHCORE GAVIN@ETHCORE.IO [eachnodedeterminis7callyreproducethe agreed computa7on [newso\wareengineeringparadigm Whichmodels? Needtobecrypto[economicsenabled Whichgovernance? TECHNICAL
TEZOSdecentralisedgovernance. Tezos: A Self-Amending Crypto-Ledger Position Paper L.M Goodman Decentralisa7onembedsgovernance,besidestrust. Consensusonhowtochangerules,alsothosethatruleconsensus. Whichmeta[?)models? TECHNICAL
TEZOSdecentralisedgovernance moreatwtsc18@fc 26/0202/03March2018 TECHNICAL
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