Byzantine Fault Tolerant (BFT) Mechanisms BDC Practice Questions (Page 5)

Questions 21–25

1. 21foundation · medium

   According to the Byzantine fault tolerance threshold, what is the minimum number of nodes (n) required to tolerate f faulty nodes?

   • An ≥ 3f + 1
   • Bn ≥ f + 1
   • Cn ≥ 2f + 1
   • Dn ≥ 4f + 1
   Reveal Solution Discussion Select an answer first
2. 22foundation · medium

   Which of the following is a practical limitation of BFT mechanisms in large-scale blockchain networks?

   • AThey cannot provide finality for transactions.
   • BThe requirement for a fixed set of validators makes it difficult to join or leave the network dynamically.
   • CThey are more energy-intensive than proof-of-work.
   • DThey require a trusted third party to resolve disputes.
   Reveal Solution Discussion Select an answer first
4. 23expert · hard

   A distributed system has 5 nodes. The system is designed to tolerate up to 1 Byzantine fault. During operation, one node sends conflicting messages to different peers. The system uses a consensus algorithm that requires a simple majority (3 out of 5) to agree. What is the likely outcome?

   • AThe system will detect the faulty node and exclude it automatically
   • BThe system may reach conflicting decisions, violating safety
   • CThe system will halt until the faulty node is removed
   • DThe system will always reach consensus correctly
   Reveal Solution Discussion Select an answer first
5. 24foundation · medium

   What is a key trade-off between HotStuff and PBFT?

   • APBFT is simpler to implement but has higher latency than HotStuff.
   • BHotStuff is more secure because it tolerates more than one-third faulty nodes.
   • CPBFT has lower communication complexity but is less secure.
   • DHotStuff has lower communication complexity but requires a more complex view-change protocol.
   Reveal Solution Discussion Select an answer first
6. 25foundation · medium

   What is the primary role of BFT in a blockchain network?

   • ATo store transaction data off-chain to reduce blockchain size.
   • BTo encrypt transactions so that only authorized parties can read them.
   • CTo speed up transaction processing by allowing parallel block creation.
   • DTo prevent double-spending by ensuring that only one version of the ledger is accepted.
   Reveal Solution Discussion Select an answer first