Alternative and Hybrid Consensus Mechanisms BDC Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard

   A startup is choosing between two hybrid consensus designs for a decentralized identity network. Design A uses proof-of-work for block production and proof-of-stake for governance. Design B uses proof-of-stake for both block production and governance. The startup values decentralization and resistance to censorship, but also wants to minimize energy consumption. Which trade-off should guide their decision?

   • ADesign B provides stronger resistance to censorship because stake is more evenly distributed than hash power
   • BDesign A is more energy-efficient because PoW is more efficient than PoS
   • CBoth designs have identical security and decentralization properties
   • DDesign A provides stronger resistance to censorship due to the permissionless nature of PoW, but at the cost of higher energy use
   Reveal Solution Discussion Select an answer first
2. 27foundation · easy

   What is a key characteristic of hybrid consensus mechanisms like the one used in Decred?

   • AThey rely exclusively on a single group of participants for all consensus decisions
   • BThey allow different types of participants to perform different roles in the consensus process
   • CThey require all participants to both mine and stake simultaneously
   • DThey eliminate the need for any form of economic incentive for participants
   Reveal Solution Discussion Select an answer first
4. 28application · medium

   A blockchain startup is designing a governance token that must resist 51% attacks from large mining pools while still allowing token holders to participate in protocol upgrades. They want to avoid a hard fork if the community disagrees with a proposed change. Which hybrid consensus approach best satisfies these requirements?

   • AProof-of-Authority where pre-approved validators from the founding team approve all upgrades
   • BDecred-style PoW + PoS hybrid where PoS stakeholders vote on proposals and lock tickets to approve or reject changes
   • CProof-of-Burn where users destroy tokens to gain mining rights and vote on upgrades
   • DPure Proof-of-Stake with delegated voting where top 21 validators decide all protocol changes
   Reveal Solution Discussion Select an answer first
5. 29expert · hard

   A blockchain architect must design a public network that achieves both high throughput (5,000 TPS) and strong decentralization (thousands of nodes). They are considering a hybrid where a small committee of validators produces blocks and a larger set of nodes verifies them. Which trade-off analysis is most accurate for this design?

   • AThis design improves throughput but reduces decentralization because the small committee has disproportionate power to censor transactions, even if the larger set can reject invalid blocks
   • BThis design sacrifices throughput for decentralization because the larger verifier set must validate every transaction, creating a bottleneck
   • CThis design achieves both high throughput and decentralization because the larger verifier set ensures no single committee member can act maliciously
   • DThis design is equivalent to pure PoW in both throughput and decentralization because both use a subset of nodes for block production
   Reveal Solution Discussion Select an answer first
6. 30application · medium

   A blockchain architect is evaluating consensus mechanisms for a public network that must achieve both high decentralization (anyone can participate) and resistance to nothing-at-stake attacks. Which hybrid consensus approach directly addresses this combination?

   • APure Proof-of-Work with no staking component
   • BProof-of-Elapsed-Time where validators wait for random timer expiration
   • CCasper FFG-style hybrid where PoW produces blocks and PoS validators finalize checkpoints
   • DPure Delegated Proof-of-Stake with 21 elected block producers
   Reveal Solution Discussion Select an answer first