Consensus Mechanism Vulnerabilities Flashcards
7 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Consensus Mechanism Vulnerabilities flashcards as text
Miner/Maximal Extractable Value (MEV) is a consensus-layer concern because:
Answer: Block producers can reorder, insert, or censor transactions for profit, risking chain reorgs
MEV incentivizes block producers to reorder or even reorganize blocks to capture value, which can destabilize consensus and harm users.
A 'time-bandit' reorg attack is motivated by:
Answer: Rewriting past blocks to capture lucrative MEV opportunities
Time-bandit attacks re-mine historical blocks specifically to seize large MEV that was available in those past blocks.
Proposer-builder separation (PBS) aims to mitigate MEV harms by:
Answer: Separating who builds block contents from who proposes them to limit centralizing advantages
PBS splits block-building from proposing so sophisticated MEV extraction doesn't centralize validator power, improving fairness and resilience.
A 'difficulty bomb' (as historically used in Ethereum PoW) was designed to:
Answer: Gradually slow block production to encourage protocol upgrades
The difficulty bomb steadily raises mining difficulty to incentivize migration away from PoW, pressuring the network toward planned upgrades.
Why can low validator/miner participation threaten consensus security?
Answer: Fewer participants lower the cost for an attacker to control a majority
When participation is low, an attacker needs less resource to reach a majority, making 51%-style attacks cheaper and more likely.
A 'censorship attack' at the consensus layer occurs when block producers:
Answer: Deliberately exclude specific transactions from blocks
Block producers can refuse to include targeted transactions, degrading censorship-resistance even without breaking ledger integrity.
Inclusion lists (a proposed mitigation) help counter censorship by:
Answer: Forcing block proposers to include certain pending transactions
Inclusion lists require proposers to add specified eligible transactions, reducing the ability of producers to censor at the consensus layer.