CBSA Enterprise Blockchain Platforms 5 — Questions and Answers
Question 1: What is the role of the 'world state' database in Hyperledger Fabric?
- It stores all historical transactions in a time-ordered ledger
- It stores the current value of all ledger keys for efficient query access (Correct answer)
- It maintains the certificate authority records for all members
- It holds pending transactions before they are ordered
Correct answer: It stores the current value of all ledger keys for efficient query access
The world state database (typically CouchDB or LevelDB) stores the latest value of each key, allowing chaincode to efficiently read current state without replaying the entire transaction history.
Question 2: A CBSA candidate is evaluating enterprise platforms. Which statement about Hyperledger Sawtooth's architecture is accurate?
- Sawtooth uses a single global ordering service like Fabric
- Sawtooth supports pluggable consensus and uses Transaction Families instead of general smart contracts (Correct answer)
- Sawtooth requires all nodes to be operated by a single organization
- Sawtooth stores data exclusively in a relational database
Correct answer: Sawtooth supports pluggable consensus and uses Transaction Families instead of general smart contracts
Hyperledger Sawtooth features pluggable consensus algorithms (including PoET) and uses Transaction Families — modular code packages — to define transaction processing rules.
Question 3: In the context of enterprise blockchain interoperability, what does Hyperledger Cactus provide?
- A cross-chain atomic swap protocol for cryptocurrency exchanges
- A framework enabling integration and interoperability between different blockchain networks (Correct answer)
- A tool for migrating chaincode from Fabric to Ethereum
- A consensus mechanism that works across heterogeneous ledgers
Correct answer: A framework enabling integration and interoperability between different blockchain networks
Hyperledger Cactus is an open-source framework that provides pluggable connectors and APIs to achieve interoperability between different distributed ledger technologies.
Question 4: Which scenario best illustrates the need for a 'notary cluster' in R3 Corda?
- When multiple organizations need to share a common ledger state
- When preventing double-spending of states across multiple transactions (Correct answer)
- When encrypting transaction data for regulatory reporting
- When scaling the number of CorDapps deployed on the network
Correct answer: When preventing double-spending of states across multiple transactions
In Corda, notary clusters validate the uniqueness of input states in transactions, preventing double-spending by ensuring the same state cannot be consumed twice.
Question 5: An enterprise architect must choose between LevelDB and CouchDB as the state database for a Hyperledger Fabric network that requires complex queries on chaincode data. Which should they choose and why?
- LevelDB, because it supports full SQL query syntax
- CouchDB, because it supports rich JSON document queries and indexes (Correct answer)
- LevelDB, because it handles higher transaction throughput with complex queries
- CouchDB, because it provides built-in encryption for sensitive data
Correct answer: CouchDB, because it supports rich JSON document queries and indexes
CouchDB supports rich JSON-based queries and indexes, making it the appropriate choice when chaincode needs to perform complex, ad-hoc queries against world state data.
Question 6: What distinguishes 'Byzantine Fault Tolerance' (BFT) consensus from 'Crash Fault Tolerance' (CFT) consensus in enterprise blockchain contexts?
- BFT requires more nodes but tolerates only hardware failures, while CFT tolerates malicious nodes
- BFT tolerates nodes that behave maliciously or send conflicting messages, while CFT only handles nodes that crash or go offline (Correct answer)
- CFT is slower but more secure than BFT for financial applications
- BFT is used only in public blockchains while CFT is exclusive to private networks
Correct answer: BFT tolerates nodes that behave maliciously or send conflicting messages, while CFT only handles nodes that crash or go offline
BFT consensus algorithms tolerate up to f malicious or arbitrarily-failing nodes in a network of 3f+1 nodes, while CFT only handles benign failures like crashes or network partitions.
Question 7: In enterprise blockchain platform selection, what is the significance of the 'finality' characteristic of a consensus mechanism?
- It determines how many nodes must participate in block creation
- It defines whether a confirmed transaction can be reversed or remain permanently settled (Correct answer)
- It specifies the maximum block size supported by the consensus algorithm
- It controls the rate at which new participants can join the network
Correct answer: It defines whether a confirmed transaction can be reversed or remain permanently settled
Transaction finality determines whether a committed transaction is irreversible — enterprise applications like payment settlement require immediate finality, whereas probabilistic finality (as in PoW) introduces settlement risk.
CBSA Enterprise Blockchain Platforms 5
What is the role of the 'world state' database in Hyperledger Fabric?