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
What distinguishes 'probabilistic finality' from 'absolute finality'?
Answer: Probabilistic finality becomes more certain over time but is never absolute
In PoW, finality grows more probable as confirmations accumulate, whereas BFT-style systems provide deterministic, absolute finality.
In Proof of Authority (PoA), what secures the network?
Answer: The identity and reputation of approved validators
PoA relies on a set of known, reputable validators whose identities are at stake.
What is the purpose of the GHOST/LMD-GHOST fork-choice rule in Ethereum?
Answer: To select the heaviest subtree of attestations as the canonical chain
LMD-GHOST chooses the chain branch with the greatest accumulated validator attestation weight.
Why is randomness (e.g., RANDAO) important in PoS validator selection?
Answer: To prevent attackers from predicting and targeting future block proposers
Unpredictable randomness stops adversaries from knowing or manipulating who will propose upcoming blocks.
What is an 'eclipse attack' in the context of consensus networks?
Answer: Isolating a node by controlling all its peer connections
An eclipse attack surrounds a victim node with attacker-controlled peers to feed it a false view of the network.
In Tendermint/Cosmos consensus, when is a block considered final?
Answer: Immediately once 2/3 of validators commit it
Tendermint provides instant finality once more than two-thirds of validators pre-commit to a block.
What does 'stake grinding' attempt to exploit?
Answer: Manipulating the randomness used to select the next block proposer
Stake grinding tries to bias the leader-selection randomness in the attacker's favor.