FREE Blockchain Developer Consensus Algorithms and Protocols Questions and Answers Flashcards
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Read the first 6 FREE Blockchain Developer Consensus Algorithms and Protocols Questions and Answers flashcards as text
What is the primary purpose of a VRF (Verifiable Random Function) in modern Proof of Stake protocols like Algorand?
Answer: To secretly and verifiably select block proposers without prior announcement
VRFs allow validators to privately determine if they are selected as block proposers and then prove this selection to others, preventing targeted attacks.
How does Proof of Authority (PoA) differ from Proof of Stake in its validator selection mechanism?
Answer: PoA relies on the real-world identity and reputation of approved validators
Proof of Authority grants block validation rights to pre-approved nodes whose operators have verified identities, staking reputation rather than tokens.
What is the CAP theorem implication that most blockchain consensus algorithms must address?
Answer: A distributed system cannot simultaneously guarantee consistency, availability, and partition tolerance
The CAP theorem states that a distributed system can only guarantee two of three properties: consistency, availability, and partition tolerance.
In Tendermint BFT, what must happen before a block is considered finalized?
Answer: More than two-thirds of validators must submit pre-commit votes for the block
Tendermint requires more than two-thirds of the validator set to sign pre-commit messages for a block, providing instant deterministic finality.
What is the nothing-at-stake problem unique to naive Proof of Stake implementations?
Answer: Validators can costlessly vote on multiple competing chain forks simultaneously
In naive PoS, validators face no cost for supporting multiple forks, so rational actors vote on every fork to maximize rewards regardless of which becomes canonical.
Which property distinguishes asynchronous BFT protocols like HoneyBadgerBFT from partially synchronous ones like PBFT?
Answer: They can reach consensus without making any timing assumptions about message delivery
Asynchronous BFT protocols like HoneyBadgerBFT guarantee liveness and safety without assuming any upper bound on message delivery time.