Blockchain Developer Consensus Mechanisms 2

Question 1

In Proof of Stake, what does 'slashing' refer to?

Accepted Answer

Penalizing a validator by destroying part of its staked funds

Answer

Slashing destroys a portion of a validator's stake as punishment for malicious or faulty behavior.

Question 2

What problem does the 'nothing-at-stake' issue describe in PoS systems?

Accepted Answer

Validators can vote on every fork at no cost

Answer

Without penalties, validators can cheaply support multiple competing forks, undermining consensus.

Question 3

Which consensus mechanism does Solana combine with Proof of Stake to order transactions?

Accepted Answer

Proof of History

Answer

Solana uses Proof of History as a cryptographic clock to timestamp and order events before PoS finalization.

Question 4

In Delegated Proof of Stake (DPoS), how are block producers chosen?

Accepted Answer

By token holders voting for delegates

Answer

DPoS lets token holders vote to elect a limited set of delegates who produce blocks.

Question 5

What is the primary purpose of a 'finality gadget' like Casper FFG?

Accepted Answer

To provide checkpoints that make blocks irreversible

Answer

Finality gadgets finalize checkpoints so that finalized blocks cannot be reverted without major economic loss.

Blockchain Practice Test