ThoughtWorks 刘尚奇 - 《用Ethereum设计联盟链系统》

1 .用Ethereum设计联盟链系统 ThoughtWorks中国区块链实践负责人 刘尚奇 

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4 . 刘尚奇 刘尚奇是ThoughtWorks全球技术战略委 员会成员，中国区区块链实践负责人。致 力于将区块链技术引入企业上下文，激发 技术驱动的业务创新。 redecentralization运动的拥护者。 

5 . Agenda • Why start from Ethereum • Challenage to achieve consortium blockchain • Real world consortium blockchain 

6 .Why 

7 . Ethereum技术特点 • It is (a) blockchain! • Permissionless P2P Networking • PoW based consensus • All-in-one implementation https://github.com/ethereum/wiki/wiki/White-Paper#mining 

8 . Ethereum技术特点 • It is (a) blockchain! • Permissionless P2P Networking • PoW based consensus • All-in-one implementation https://medium.com/blockchannel/tools-and-technologies-in-the-ethereum- ecosystem-e5b7e5060eb9 

9 . Ethereum技术特点 • It is (a) blockchain! • Permissionless P2P Networking • PoW based consensus • All-in-one implementation https://www.searchenginegenie.com/101-articles/Sybil-attack.html 

10 . Ethereum技术特点 • It is (a) blockchain! • Permissionless P2P Networking Ethereum Node • PoW based consensus • All-in-one implementation 

11 .Challenage to achieve consortium blockchain 

12 . Requirement for consortium blockchain • Permissioned Network • Data Privacy • Flexible Consensus 

13 . Permissioned Network • Participant should be mapped to realworld identity • Participant require permission to the network • Exiting mechanism for retired participant 

14 . Permissioned Network However in Ethereum • Identity is anonymous and decentralized generated • Node is decoupled from Identity and both of them could join network freely • No retirement mechanism 

15 . Permissioned Network: approach Identity Node Registry Registry • Manage Identity in a registry Participant Mgmt • Binding node with an Identity • Permissioned-nodes list to Ethereum Ethereum Ethereum determine whom to connect Node Node Node Party A Party B Party B with 

16 . Permissioned Network: approach Identity Registry (Smart Contract) • Manage Identity in a registry • Binding node with an Identity • Permissioned-nodes list to Ethereum Ethereum Ethereum determine whom to connect Node Node Node Party A Party B Party B with Permissioned –node Permissioned –node Permissioned –node list in DHT list in DHT list in DHT 

17 . Data privacy • Confidential ledger data should be visible by limited participants • Transaction should be sent through limited participant 

18 . Data privacy However in Ethereum • Ledger data is open and transparant to all • Transactions are sent to global network for consensus 

19 . Data privacy: approach Part A, Part B, Part C • Have multiple chains Part A, Part C Part B, Part C 

20 . Flexible Consensus • No more PoW/PoS needed • Higher performance and lower cost • Alternative Consensus Mechanisms in different trust environment 

21 . How does consensus work, exactly? • Consensus on transaction order • Consensus on transaction validataion 

22 . How does consensus work, exactly? • Packing the transaction into block • Compete for the proposer • Choose the proposer • Validate transaction and accept the block 

23 . Flexible Consensus: approach Tx Tx Packer Packer Node 1 Node 2 • Designate dedicated node as transaction packer Ethereum Ethereum Ethereum Node Node Node Party A Party B Party C 

24 . Real world consortium blockchain 

25 . Hyperledger Fabric MSP: Fabric CA Node Registry https://vitalflux.com/quick-glance-at-hyperledger-fabric-architecture/ 

26 . Corda Node Registry https://docs.corda.net/permissioning.html https://docs.corda.net/key-concepts-ledger.html 

27 . Quorum Node Registry https://github.com/jpmorganchase/quorum/wiki/Transaction-Processing https://github.com/jpmorganchase/quorum/wiki/QuorumChain-Consensus 

28 . Patterns/Budilding Block for consortium blockchain • Participant Mgmt Service • Multiple chains/Ledger Segregation • Designate dedicated node as transaction packer 

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