blockchain & smart contracts under the hood...blockchain & smart contracts under the hood...
TRANSCRIPT
B lockcha in & Smar t Cont rac t s Under The Hood
KristofVerslypeSmalsResearch-smalsresearch.be
www.cryptov.net
Overheidscongres–15mei2018–Brussel
BlockchainisaboutTrust
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BlockchainNetwork
RegistraEonoffacts EnforcementofrulesTransferofassets
Idea
3
TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
Itransfer0,4BTCto
Ok!
Ok!
Ok!
0,4BTC→Bob
Alice
Charlie
Dave
0,4BTC→
0,4BTC→
0,4BTC→
Idea
4
TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
Itransfer0,4BTCto
Ok!
Ok!
Ok!
0,4BTC→Bob
Alice
Charlie
Dave
0,4BTC→
0,4BTC→
0,4BTC→
Blockchain
AtomicEveryonewritestransacKoninhis/herappend-onlyspreadsheetornoone→Consensusmechanism
ValidOnlyvalidtransacKonsacceptedbythenetworkE.g.bobownsthemoney&didnotyetspentitpreviously
Secure&robustSystemsfuncKons,evenifpartofmembersofflineormalicious
RelaEvelyfast
Distributed
Blockchain
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AtpredeterminedfrequencynewblockappendedwithmostrecenttransacKons
TransacKoninblockchaincannotberemoved
blockchaincontainsALLtransacKons
Blockchain=concatenaKonofblocks,whichcontaintransacKons
ManyenKKespossessthesamecopyoftheblockchain
Block51
Header
Block52
Header
Block53
Header Header
Block54
5,10BTC→
0,70BTC→
0,40BTC→
Idea
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TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
TransacEons
5,1BTC→
0,7BTC→
0,4BTC→Bob
Alice
Charlie
Dave
0,4BTC→
0,4BTC→
0,4BTC→
Pseudonyms&Keys
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0,40BTC→ 0,40BTC→Not but
RequiredtodigitallysignatransacKoninthenameofthecorrespondingpseudonym
Network
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BlockcreatorFullnodeLightnode
Blockchain
append-onlyBitcoinhistory
UTXO
RelevantinfoMostrecentstate
UTXO
UTXO
UTXO
UTXO
UTXOUTXO
UTXO
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Permissionless Permissioned
Accessible&usablebywholeworld Extralayerforaccesscontrol
OLerveryinefficient Muchmoreefficient
Trustdistributed Trustdecentralized
Cryptocurrencyrequired Nocryptocurrencyrequired
Publ i c / open Enterpr i se / ConsorEum
Slower Faster(moretx/s,moreblocks/s)
BlockchainisaboutTrust
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BlockchainNetwork
RegistraEonoffacts EnforcementofrulesTransferofassets
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RegistraKonofFacts
VaccinaEon
IdenEtyDiplomaMarriage
Medicalrecords
TaxesSupplychainTracking
Drivinglicense
PoliEcalmandates
(Official)documents
History/Overview
Will
5f3bfa419c63be2a3a09adbd0630c51f645eb03abafcd5f2ad39637a306b4177
Will
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RegistraKonofFacts
Will
Block51
Header
Block52
Header
Block53
Header Header
Block54
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TransferofAssets
Tickets.bitDomainnames
Copyright
Bitcoin Monero Ethereum
Cryptocurrencies(Virtueleassets)
Untangibleassets
DiamondsCarsLandregistry
Tangibleassets
Electricity
EnforcementsofAgreements
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ProcessingmedicalprescripEons
ElecEons
BlockingrentguaranteeCrowdfundingApplicaEon&Payment
ofsubsidies/benefits
SmartlocksTransportcondiEons
AgreementsbetweenparKesthatdonottrust eachother, withouttrusted intermediary
FlightDelayInsurance
PermissionsaccessPIIAucEon
SmartContracts
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ContractAucKon{funcKonbid()funcKongetMoney()
HighestBid:ΞHighestBidder:Beneficiary:Charlie} bid(),20Ξ
getMoney()
bid(),10Ξ
20Ξ
02010
Bob
Alice
Charlie
Alice10Ξ
Bob
Canreceive,blockandspentvalue
NosingleenKtycaninfluencecorrectfuncKoning Deafandblind
ReacKve
Ether(Ξ)isthecryptocurrencyonEthereum
SmartContractBlockchain
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contractc
Header
Block51
c.bid(),10Ξ
Header
Block52
Header
Block53
c.bid(),20Ξ
Header
c.getMoney()
Block54
ContractdeploytransacKon FuncKoninvoke
transacKon
Network
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BlockcreatorValidaKng(full)nodeLightnode
Blockchain
Append-onlyHistoryofsmartcontracts
Smartcontract
ChangeablebyfuncKoncallsActualstateofsmartcontract
SmartContracts-Summarized
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AutomaEngrules&enforcementofagreements
BetweenparEesthatdonotneedtotrusteachother100%
Withoutdependencyonasingle,intermediateparty
Privacy&ConfidenKality
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Permissionless Permissioned
ParEcipantsonlyknownunderpseudonymOneparKcipantcanhavemulKplepseudonyms
Publ ic / open Enterpr i se / ConsorEum
OnlyparEcipantshaveaccesstoblockchain
EncrypEoncanhidedataintransacEons&smartcontractsforpartofthenetwork
Tradepla`ormswillbeobligedbyEuropetostronglylinkpseudonymstoidenEtyof
theircustomers.Youneedcryptocurrenciestopublishasmartcontractortointeractwithit
Everyonecaninspecttheblockchain
AccesscontrollayercanidenEfypseudonyms
DataintransacEons&smartcontractsforeveryonereadable
Notalldatanecessarilystoredontheblockchainitself
Remark:TheparKcipantsthatcollecKvelysecureasmartcontract,needaccesstothissmartcontractstate&codeandtotherelevanttransacKons
20hjps://www.theguardian.com/technology/2017/nov/08/cryptocurrency-300m-dollars-stolen-bug-ether
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Permissionless PermissionedPubl ic / open Enterpr i se / ConsorEum
Howtoreducerisk?- Developersneedproperbackground
Smartcontractcodelooksfamiliar,butbehavessomewhatdifferently.- Minimizesmartcontractcode- TesEngencodeverificaEon
FutureformalverificaKon
BugsinSmartContracts
SmartcontractmoreeasilyupdatableHard/impossibletoupdatesmartcontract
AbackercanbeeasilyidenEfiedHardertoidenEfyabacker
FutureFuncKonality
22hjp://www.the-blockchain.com/docs/Hyperledger%20Whitepaper.pdf
BlockchaininteracEon“HyperledgersKllrequiresanaddressingsystemthatallowstransacKonsononeledger to discover and uKlize appropriate transacKons and smart contracts(chaincode)onotherledgers.” FABRIC
BlockchaintruncaEonAper a voKng round, theoldest part of theblockchain that hasbecomedeadweight, can be collecKvely forgojen. This feature will help to keep theblockchainmanageable.
Twoexamplesofusefulfeaturesthatdonotyetexistincurrentblockchainpla`orms.However,theblockchaincommunityisworkingonit.
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Dr.KristofVerslype
Researcher, advisor&speakerincrypto, privacy&blockchaintech
Qu e s E o n s & C o n t a c t
©BenjaminReay
@KristofVerslype
be.linkedin.com/in/verslype
www.cryptov.net
www.smalsresearch.be
@SmalsResearch
www.smals.be
@Smals_ICT
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