CBP Bitcoin Transactions and Wallets 2

Question 1

What is the purpose of the 'locktime' field in a Bitcoin transaction?

Accepted Answer

Specifies the earliest block height or timestamp at which the transaction can be included

Answer

Locktime specifies the earliest block height or Unix timestamp before which the transaction cannot be mined into a block.

Question 2

In a Bitcoin wallet, what does a BIP39 mnemonic seed phrase represent?

Accepted Answer

An entropy value encoded as human-readable words used to derive a hierarchical deterministic wallet

Answer

BIP39 encodes entropy as 12–24 human-readable words that serve as the root seed for deriving all keys in an HD wallet.

Question 3

What happens to the UTXOs used as inputs when a Bitcoin transaction is confirmed?

Accepted Answer

They are marked as spent and removed from the UTXO set

Answer

Confirmed transaction inputs are consumed and their UTXOs are permanently removed from the UTXO set.

Question 4

Which script type requires multiple private keys to authorize a transaction?

Accepted Answer

P2SH multisig

Answer

P2SH multisig (Pay-to-Script-Hash) wraps a redeem script requiring M-of-N signatures to spend funds.

Question 5

What is 'change' in the context of a Bitcoin transaction?

Accepted Answer

Leftover value from a consumed UTXO sent back to the sender

Answer

When a UTXO's value exceeds the payment amount, the excess is sent to a change address controlled by the sender.

(CBP) Certified Bitcoin Professional Practice Test