Consensus Algorithms and Protocols 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 Algorithms and Protocols flashcards as text
In Practical Byzantine Fault Tolerance (PBFT), how many total nodes are required to tolerate f faulty nodes?
Answer: 3f + 1
PBFT requires 3f + 1 total nodes to safely tolerate f Byzantine faults.
What problem does the 'nothing-at-stake' issue describe in Proof of Stake systems?
Answer: Validators can cheaply vote on multiple competing chains
Nothing-at-stake means validators face no cost to validate multiple forks, undermining consensus.
In Proof of Work, what does the 'difficulty' parameter primarily control?
Answer: The expected time to find a valid block
Difficulty adjusts how hard the hash puzzle is to keep block times roughly constant.
Which consensus mechanism does Ethereum use after 'The Merge'?
Answer: Proof of Stake
Ethereum transitioned from Proof of Work to Proof of Stake during The Merge in 2022.
What is a key characteristic of Delegated Proof of Stake (DPoS)?
Answer: Token holders vote for a limited set of block producers
In DPoS, stakeholders elect a small group of delegates who produce blocks on their behalf.
What does 'finality' mean in a blockchain consensus context?
Answer: The point at which a transaction cannot be reversed
Finality is the guarantee that a committed transaction is permanent and irreversible.
Which attack involves an entity controlling more than half of a network's mining or staking power?
Answer: 51% attack
A 51% attack lets an attacker control the majority of hashpower or stake to rewrite history.