Lecture 8 Hyperledger Fabric 2022f.pdf
- 1. Blockchain Technology and Applications Dr Shoab Ahmed Khan Lecture 8 11/19/22 1
- 2. 1. UTXOs and HODL 2. Central Bank Digital Currency (CBDC) 3. Hands on Smart Contract Outline Lec 7 11/19/22 2
- 3. 1. Permissioned Blockchain 2. Hyperledger Fabric 3. Example Outline Lec 8 11/19/22 3
- 7. What is Hyperledger Fabric? •The Linux Foundation founded the Hyperledger project in 2015 to advance cross-industry blockchain technologies
- 8. Private and Permissioned • Unlike permissionless blockchain networks, not everyone can become part of the network •It is private and permissioned
- 9. Final State of Sample Network
- 10. Final State of Sample Network CASE-FAST FAST-NUST CASE Student NUST Student FAST Student CASE/FAST Registration FAST/NUST Registration HEC R1: CASE R2: FAST R3: NUST R4: HEC
- 11. Hyperledger Fabric • Organizations R1, R2, R3 and R4 contribute infrastructure to the network • The organizations have jointly decided, that they will set up a Hyperledger Fabric network. • R4 has been assigned to be the network initiator • it has been given the power to set up the initial version of the network. • R4 has no intention to perform business transactions on the network. • R1 and R2 have a need for a private communications within the overall network, as do R2 and R3. • Organization R1 has a client application that can perform business transactions within channel C1. • Organization R2 has a client application that can do similar work both in channel C1 and C2. • Organization R3 has a client application that can do this on channel C2.
- 12. Setting Blockchain Network • CASE, FAST, NUST, HEC • HEC is the Initiator •R1 -> CASE •R2 -> FAST •R3 -> NUST •R4-> HEC
- 13. Hyperledger Fabric • Organizations CASE, FAST, NUST and HEC contribute infrastructure to the network • The organizations have jointly decided, that they will set up a Hyperledger Fabric network. • HEC has been assigned to be the network initiator • it has been given the power to set up the initial version of the network. • HEC has no intention to perform business transactions on the network. • CASE and FAST have a need for a private communications within the overall network, as do FAST and NUST. • Organization CASE has a client application that can perform business transactions within channel C1. • Organization FAST has a client application that can do similar work both in channel C1 and C2. • Organization NUST has a client application that can do this on channel C2.
- 14. Hyperledger Fabric • Peer node P1 maintains a copy of the ledger L1 associated with C1. • Peer node P2 maintains a copy of the ledger L1 associated with C1 and a copy of ledger L2 associated with C2. • Peer node P3 maintains a copy of the ledger L2 associated with C2. • Channel C1 is governed according to the policy rules specified in channel configuration CC1 • The channel is under the control of organizations R1 and R2. • Channel C2 is governed according to the policy rules specified in channel configuration CC2 • the channel is under the control of organizations R2 and R3.
- 15. Hyperledger Fabric • There is an ordering service O4 that services as a network administration point for N, and uses the system channel. • The ordering service also supports application channels C1 and C2, for the purposes of transaction ordering into blocks for distribution • Each of the four organizations has a preferred Certificate Authority.
- 16. Who gives permission? MSP • The members of a Hyperledger Fabric network enroll through a trusted Membership Service Provider (MSP)
- 17. Channels • Ability to create channels, allowing a group of participants to create a separate ledger of transactions
- 18. Smart Contract • Hyperledger Fabric smart contracts are written in chaincode • They are invoked by an application external to the blockchain •when that application needs to interact with the ledger
- 20. Designing Blockchain on Hyperledger Fabric
- 21. Blockchain
- 22. Blockchain Nodes • Consists of three different types of nodes 1. Peer 2. Orderer 3. Client •All nodes are identified by a Membership Service Provider (MSP) and owned by different organizations
- 23. Nodes •Client submits transactions •Peer maintains the blockchain ledger in the form of a hash chain and records the current state with a key-value store •Endorser is responsible for executing chaincode to endorse transaction proposals •Committer just updates the ledger state by validating and committing transactions
- 24. Orderer •Orderer implements the ordering service •produces the total sequence for all the transactions and batch them into blocks
- 25. Endorsement policy •The endorsement policy specifies a set of peers that are required to endorse transaction proposals •Transactions are marked as valid only if they have been properly endorsed by specified peers based on the endorsement policy •It is formed by the monotone logical expression on sets, such as “AND” and “OR”.
- 26. Ledger •In Fabric, a ledger consists of two parts •world state •blockchain •World state holds the latest ledger state in the form of a versioned key-value store •The blockchain ledger is maintained by all peers,
- 27. Channel •Channel is a logical structure formed by a collection of specific network members •Each channel allows a group of peers to create a completely separate ledger •In Fabric, a subset of organizations that want to conduct business transactions privately can generate a channel, thus maintaining a partition ledger •One organization can join multiple channels simultaneously for a distinct purpose
- 28. Processing of Transaction Hyperledger Fabric has three major stages in processing a transaction, namely, endorsing, ordering/batching and validating/committing
- 32. Blockchain
- 33. A peer hosts instances of ledgers and instances of chaincodes
- 34. Key-Value Pair •A key-value pair consists of two related data elements •A key, which is a constant that defines the data set (e.g., gender, color, price) • A value, which is a variable that belongs to the set (e.g., male/female, green, 100)
- 35. Key Value Pair •gender = male •color = green •price > 100
- 36. WorldState
- 37. World State • An application program can invoke a smart contract which uses simple ledger APIs to get, put and delete states. •Notice how a state value can be simple (Audi…) or compound (type:BMW…) •The world state is often queried to retrieve objects with certain attributes, for example to find all red BMWs
- 38. World State Only transactions that are signed by the required set of endorsing organizations will result in an update to the world state
- 40. •The ledger, L, comprises a world state, W and a blockchain, B. W contains four states with keys: ASSET1, ASSET2, ASSET3, and ASSET4. B contains two blocks, 0 and 1. Block 1 contains four transactions: T1, T2, T3, T4
- 51. Multiple Peers
- 52. A Peer with Multiple Ledgers • A peer hosting multiple ledgers. • Peers host one or more ledgers, and each ledger has zero or more chaincodes that apply to them. Peer P1 hosts ledgers L1 and L2. Ledger L1 is accessed using chaincode S1 Ledger L2 can be accessed using chaincodes S1 and S2.
- 53. A peer may have many ledger and chaincode • Peer P1 hosts ledgers L1 and L2 • L1 is accessed by chaincodes S1 and S2, L2 is accessed by S1 and S3. • S1 can access both L1 and L2.
- 54. Application Interacting with the Peers
- 55. Peers and Channels Channels allow a specific set of peers and applications to communicate with each other within a blockchain network. application A can communicate directly with peers P1 and P2 using channel
- 56. Peers and Organizations • Four organizations contributing eight peers to form a network. • The channel C connects five of these peers in the network N — P1, P3, P5, P7 and P8. • The other peers owned by these organizations have not been joined to this channel, but are typically joined to at least one other channel.
- 57. Peers and Identity • P1 and P2 have identities issued by CA1 • Channel C determines from a policy in its channel configuration that identities from CA1 should be associated with Org1 using ORG1.MSP. • Similarly, P3 and P4 are identified by ORG2.MSP as being part of Org2.
- 58. Peers and Orderers •An update transaction is quite different from a query transaction because a single peer cannot, on its own, update the ledger •updating requires the consent of other peers in the network. •This process is called consensus, which takes much longer to complete than a simple query. •But when all the peers required to approve the transaction do so, and the transaction is committed to the ledger, peers will notify their connected applications that the ledger has been updated.
- 60. Phase 2: Ordering and packaging transactions into blocks
- 61. Ordering Service Implementation •Raft (recommended) •Kafka (deprecated in v2.x) •Solo (deprecated in v2.x)
- 62. Phase 3: Validation and commit
- 63. Read-Write Set
- 64. Read-Write Set Note: the version number is based on incremental order which basically derived from the height of committing transactions.
- 65. •validation is done for stopping Double spending
- 67. Read-Write Set
- 68. Write Set stored in World State DB
- 69. Tx 2 will get decline and thus double spending will be avoided.
- 74. Summary
- 75. 11/20/22 75 https://www.ibm.com/downloads/cas/APGWOG5A IBM Blockchain Services for SCM
- 76. 11/20/22 76
- 77. 11/20/22 77 IBM Blockchain Services for SCM
- 78. Supply Chain Management Blockchain for SCM in Textile Industry
- 79. Blockchain for SCM in Textile Industry & Stakeholders
- 82. Generating Public/Private Key Pair for Blockchain SCM
- 84. •A blockchain would not replace the broad range of transaction-processing, accounting, and management-control functions performed by ERP systems, such as invoicing, payment, and reporting. Blockchain and ERP
- 85. •The blockchain would interface with legacy systems across participating firms. •Each firm would generate blocks of transactions from its internal ERP system and add them to the blockchain. •This would make it easy to integrate various flows of transactions across firms. Blockchain and ERP