Consensus Mechanisms 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 Mechanisms flashcards as text
In Proof of Stake, what does 'slashing' refer to?
Answer: Penalizing a validator by destroying part of its staked funds
Slashing destroys a portion of a validator's stake as punishment for malicious or faulty behavior.
What problem does the 'nothing-at-stake' issue describe in PoS systems?
Answer: Validators can vote on every fork at no cost
Without penalties, validators can cheaply support multiple competing forks, undermining consensus.
Which consensus mechanism does Solana combine with Proof of Stake to order transactions?
Answer: Proof of History
Solana uses Proof of History as a cryptographic clock to timestamp and order events before PoS finalization.
In Delegated Proof of Stake (DPoS), how are block producers chosen?
Answer: By token holders voting for delegates
DPoS lets token holders vote to elect a limited set of delegates who produce blocks.
What is the primary purpose of a 'finality gadget' like Casper FFG?
Answer: To provide checkpoints that make blocks irreversible
Finality gadgets finalize checkpoints so that finalized blocks cannot be reverted without major economic loss.
In a Byzantine Fault Tolerant system tolerating f faulty nodes, what is the minimum total number of nodes required?
Answer: 3f + 1
Classical BFT consensus requires at least 3f + 1 nodes to tolerate f Byzantine faults.
What does 'weak subjectivity' mean in Proof of Stake networks?
Answer: Nodes need a recent trusted checkpoint to sync safely
New or long-offline nodes must rely on a recent trusted checkpoint to avoid long-range attacks.