Challenges in Blockchain Consensus Mechanisms BFC Practice Questions (Page 3)

Questions 11–15

1. 11expert · hard

   A blockchain platform for a central bank digital currency (CBDC) must process the entire country's retail payment volume, which peaks at 50,000 transactions per second. The central bank also requires that transactions be final within 1 second and that the network remain operational even if several nodes fail. Which consensus design would best meet these requirements?

   • AA public Proof of Stake network with an open validator set
   • BA permissioned network using a variant of Practical Byzantine Fault Tolerance with a small validator set and sharding
   • CA public Proof of Work network with a large mining pool
   • DA single-node Raft consensus
   Reveal Solution Discussion Select an answer first
2. 12application · medium

   A global remittance company is choosing a blockchain for cross-border payments. They must comply with anti-money laundering (AML) regulations that require transaction monitoring and the ability to freeze suspicious accounts. Which consensus mechanism feature would most directly support these compliance requirements?

   • AOpen participation for all validators
   • BLow energy consumption
   • CHigh transaction throughput
   • DPermissioned validator set with known identities
   Reveal Solution Discussion Select an answer first
4. 13expert · hard

   A new blockchain project is choosing between Proof of Work and Proof of Stake. The team is particularly worried about the 'rich getting richer' problem, where the largest stakeholders can dominate the network. Which consensus mechanism is more susceptible to this concentration of power, and what is the primary mitigation?

   • AProof of Stake is more susceptible; mitigation includes slashing conditions and delegation limits
   • BBoth are equally susceptible; mitigation is to increase block rewards
   • CProof of Work is more susceptible; mitigation includes ASIC-resistant algorithms
   • DNeither is susceptible because consensus is decentralized by design
   Reveal Solution Discussion Select an answer first
5. 14application · medium

   A public blockchain project is considering a protocol upgrade that would change the consensus mechanism from Proof of Work to Proof of Stake. The community is divided, and a significant minority of miners oppose the change. The project team wants to avoid a permanent network split. What should they prioritize?

   • AImplementing the upgrade immediately to show decisiveness
   • BDelegating the decision to a small group of core developers
   • CIgnoring the opposition and proceeding with the upgrade
   • DEngaging in governance processes to build consensus
   Reveal Solution Discussion Select an answer first
6. 15foundation · easy

   How does a permissioned consensus mechanism, such as PBFT, help address regulatory compliance in financial systems?

   • AIt allows for the identification of validators, enabling regulators to enforce compliance requirements on known entities.
   • BIt automatically encrypts all transactions, making them invisible to regulators.
   • CIt eliminates the need for any regulatory oversight because the network is private.
   • DIt ensures that all transactions are irreversible, which satisfies regulatory requirements for finality.
   Reveal Solution Discussion Select an answer first