CBCP Consensus Mechanisms and Mining 5 — Questions and Answers
Question 1: What is 'Proof of Burn' consensus and what is its primary theoretical benefit?
- Miners burn electricity to power ASICs, reducing energy waste
- Participants destroy cryptocurrency to earn the right to mine, creating a verifiable cost without ongoing hardware requirements (Correct answer)
- Validators burn transaction fees to maintain network security
- A mechanism that destroys invalid transactions to clean the mempool
Correct answer: Participants destroy cryptocurrency to earn the right to mine, creating a verifiable cost without ongoing hardware requirements
Proof of Burn requires participants to send coins to an unspendable address, creating an irreversible sunk cost that grants mining rights proportional to coins destroyed.
Question 2: What is the 'CAP theorem' and how does it apply to blockchain consensus design?
- Consistency, Availability, and Partition tolerance cannot all be simultaneously guaranteed; blockchains must choose two (Correct answer)
- Consensus, Atomicity, and Persistence are the three required properties of any blockchain
- Cost, Accuracy, and Performance are the primary metrics for evaluating consensus algorithms
- The theorem states blockchains can achieve complete decentralization with sufficient compute
Correct answer: Consistency, Availability, and Partition tolerance cannot all be simultaneously guaranteed; blockchains must choose two
CAP theorem states distributed systems can guarantee at most two of Consistency, Availability, and Partition tolerance; PoW chains sacrifice consistency (probabilistic finality) for availability and partition tolerance.
Question 3: In Avalanche consensus, what is the 'snowball' mechanism?
- A method of rolling up transactions into batches before consensus
- A repeated random sampling process where a node queries peers and shifts preference based on majority responses until confidence thresholds are met (Correct answer)
- A protocol for merging competing chain branches into a single DAG
- An algorithm that removes the lowest-staking validators from the active set
Correct answer: A repeated random sampling process where a node queries peers and shifts preference based on majority responses until confidence thresholds are met
Avalanche's Snowball algorithm has each node repeatedly sample random subsets of peers, updating its preference toward the majority answer until the network converges with high probability.
Question 4: What is the significance of the 'difficulty bomb' in Ethereum's transition from PoW to PoS?
- It increased transaction fees exponentially to discourage PoW usage
- It was an exponentially increasing difficulty adjustment designed to make PoW mining progressively impractical, encouraging the move to PoS (Correct answer)
- It destroyed mining hardware remotely via a software update
- It reduced block rewards to zero to starve miners of income
Correct answer: It was an exponentially increasing difficulty adjustment designed to make PoW mining progressively impractical, encouraging the move to PoS
The difficulty bomb was deliberately coded into Ethereum to exponentially slow PoW block production over time, creating an 'ice age' that would force the network to transition to Proof of Stake.
Question 5: What is 'Tendermint' consensus and which projects use it?
- A PoW variant with instant finality used by Bitcoin Cash
- A BFT-based PoS consensus engine providing instant finality, used as the foundation for Cosmos SDK chains (Correct answer)
- A DAG-based consensus used exclusively by IOTA
- A federated consensus mechanism developed for Stellar
Correct answer: A BFT-based PoS consensus engine providing instant finality, used as the foundation for Cosmos SDK chains
Tendermint is a BFT consensus algorithm providing deterministic finality after each block, forming the consensus layer of the Cosmos SDK and chains like Cosmos Hub and Binance Chain.
Question 6: In mining economics, what is the 'block subsidy' and how does it change over time in Bitcoin?
- A government subsidy paid to encourage sustainable mining; remains fixed
- The newly created Bitcoin awarded to the miner who finds each block; halves approximately every four years (Correct answer)
- A fee paid by the network to compensate for electricity costs; increases with difficulty
- A pool payout mechanism distributing rewards equally; resets annually
Correct answer: The newly created Bitcoin awarded to the miner who finds each block; halves approximately every four years
The block subsidy is the amount of new Bitcoin created per block (starting at 50 BTC), which halves every 210,000 blocks (~4 years) in an event called the 'halving,' ultimately capping supply at 21 million BTC.
Question 7: What distinguishes 'chain-based' PoS from 'committee-based' BFT PoS consensus?
- Chain-based PoS uses a single validator; BFT uses multiple validators simultaneously
- Chain-based PoS selects a validator per slot who extends the longest chain (probabilistic finality); committee-based BFT uses voting rounds for deterministic finality per block (Correct answer)
- Chain-based PoS requires more stake; BFT requires less stake to participate
- Chain-based PoS is used only on permissioned blockchains; BFT is used on public networks
Correct answer: Chain-based PoS selects a validator per slot who extends the longest chain (probabilistic finality); committee-based BFT uses voting rounds for deterministic finality per block
Chain-based PoS (like early Ethereum beacon chain proposals) mimics PoW's fork-choice rule with validators, while BFT committee consensus (like Tendermint) uses multi-round voting to commit blocks with absolute finality.
CBCP Consensus Mechanisms and Mining 5
What is 'Proof of Burn' consensus and what is its primary theoretical benefit?