Blockchain 101 Certification Blockchain 101 Certification Consensus Mechanisms & Protocols 2

Question 1

What is the primary purpose of a nonce in Proof of Work mining?

Accepted Answer

To find a hash that meets the difficulty target

Answer

Miners increment the nonce value repeatedly until the resulting block hash falls below the current difficulty target.

Question 2

What does 'finality' mean in blockchain consensus?

Accepted Answer

The irreversibility of a confirmed transaction

Answer

Finality means that once a transaction is confirmed, it cannot be reversed or altered, providing certainty to participants.

Question 3

Which consensus algorithm uses a 'leader election' process to designate one node to propose each block?

Accepted Answer

Raft Consensus

Answer

Raft Consensus elects a single leader node to manage log replication and propose new entries to the cluster.

Question 4

What is the '51% attack' in blockchain security?

Accepted Answer

When an attacker controls the majority of mining/staking power

Answer

A 51% attack occurs when a single entity controls more than half of the network's consensus power, enabling transaction manipulation.

Question 5

What is 'chain reorganization' (reorg) in a blockchain network?

Accepted Answer

Replacing a portion of the chain with a longer competing chain

Answer

A chain reorganization happens when the network switches to a longer competing chain, making previously confirmed blocks orphaned.

Blockchain 101 Certification Practice Test