CBDH Consensus & Transaction Validation Flashcards

What is the primary consensus mechanism used in Hyperledger Fabric?

Answer: Execute-Order-Validate (EOV)

Fabric uses an Execute-Order-Validate architecture where transactions are executed by endorsers, ordered by the ordering service, then validated by all peers.

Which component in Hyperledger Fabric is responsible for ordering transactions into blocks?

Answer: Ordering service (orderer)

The ordering service receives endorsed transactions, orders them deterministically, and broadcasts blocks to all channel peers.

What consensus algorithm does Hyperledger Fabric's Raft-based ordering service use?

Answer: Crash Fault Tolerant (CFT) Raft

Fabric's Raft ordering service uses the Crash Fault Tolerant (CFT) Raft algorithm, tolerating up to (n-1)/2 orderer failures.

What is an 'endorsement policy' in Hyperledger Fabric?

Answer: A policy specifying which peers must simulate and sign a transaction proposal

An endorsement policy defines which organizations' peers must execute chaincode and cryptographically sign the results for a transaction to be valid.

During Hyperledger Fabric transaction flow, what does a client do after collecting endorsements?

Answer: Submits the endorsed transaction to the ordering service

After gathering sufficient endorsements, the client packages the proposal responses into a transaction envelope and submits it to the ordering service.

What happens during the 'validate' phase of Fabric's Execute-Order-Validate flow?

Answer: Peers verify endorsement policy compliance and detect read-write set conflicts

During validation, each committing peer checks that endorsement policies are satisfied and that the read set versions match the current world state to prevent MVCC conflicts.