Alternative and Hybrid Consensus Mechanisms BDC Practice Questions (Page 8)

Questions 36–38

1. 36expert · hard

   A blockchain architect is evaluating a hybrid consensus that uses PoW for block production and PoS for finality. They notice that the PoS finality layer is vulnerable to a 'liveness attack' where validators stop voting, causing finality to stall. Which mitigation strategy is most effective while preserving the hybrid design?

   • ARemove the PoS finality layer and rely solely on PoW confirmations
   • BAllow PoW miners to finalize blocks if PoS validators don't vote within a time limit
   • CImplement an inactivity leak where validators who stop voting have their stake gradually reduced, incentivizing them to resume participation
   • DIncrease the PoW difficulty to make block production slower, giving validators more time to vote
   Reveal Solution Discussion Select an answer first
2. 37foundation · easy

   What is the primary purpose of a hybrid consensus mechanism in a blockchain network?

   • ATo replace all existing consensus algorithms with a single standardized protocol
   • BTo eliminate the need for network validators by using a fully automated decision-making process
   • CTo increase the block size limit while keeping the same consensus rules
   • DTo combine features from different consensus algorithms to achieve a balance of security, scalability, and decentralization
   Reveal Solution Discussion Select an answer first
3. 38application · medium

   A blockchain project wants to reduce the energy consumption of its current PoW system but is concerned that switching to pure PoS will make it vulnerable to long-range attacks where an attacker rewrites history from an early point. Which hybrid consensus approach addresses this concern?

   • AProof-of-Burn where users burn tokens to gain mining rights
   • BPure Proof-of-Stake with weak subjectivity checkpoints
   • CPure Proof-of-Stake with no checkpointing mechanism
   • DPoW + PoS hybrid where PoW continues to secure the chain history and PoS is used only for governance and finality checkpoints
   Reveal Solution Discussion Select an answer first