CBSA Core Blockchain Principles 2

Question 1

What property of a Merkle tree allows efficient proof that a specific transaction is included in a block without downloading the entire blockchain?

Accepted Answer

Merkle proof (SPV proof)

Answer

A Merkle proof (used in Simplified Payment Verification) requires only a logarithmic number of hashes to prove inclusion without the full dataset.

Question 2

In blockchain terminology, what does 'finality' refer to?

Accepted Answer

The guarantee that a confirmed transaction cannot be reversed

Answer

Finality means a transaction is irrevocably settled and cannot be altered, rolled back, or double-spent after confirmation.

Question 3

Which type of blockchain fork occurs when nodes permanently diverge because they follow different protocol rules?

Accepted Answer

Hard fork

Answer

A hard fork introduces backward-incompatible rule changes, causing non-upgraded nodes to follow a different chain permanently.

Question 4

What role does a cryptographic nonce serve in Proof of Work mining?

Accepted Answer

It is a number miners increment to find a hash meeting the difficulty target

Answer

Miners repeatedly change the nonce value until the resulting block hash falls below the network's current difficulty target.

Question 5

What is the primary purpose of the UTXO (Unspent Transaction Output) model used in Bitcoin?

Accepted Answer

To track coin ownership by recording spendable outputs rather than account balances

Answer

The UTXO model represents value as discrete unspent outputs, preventing double-spend without requiring a global account ledger.

(CBSA) Certified Blockchain Solution Architect Practice Test