CBP - Certified Bitcoin Professional Blockchain and Transaction Mechanics Questions and Answers

Question 1

In the Bitcoin network, what is the primary role of the mempool?

Accepted Answer

A waiting area for unconfirmed transactions before they are included in a block.

Answer

The mempool (memory pool) is a node's holding area for transactions that have been broadcast to the network but have not yet been included in a block. Miners select transactions from their mempool to build a new block.

Question 2

A user sends 1 BTC from an address that holds a single UTXO of 3 BTC. The transaction has one output of 1 BTC to the recipient. Which of the following accurately describes the outputs of this transaction?

Accepted Answer

Two outputs: one of 1 BTC to the recipient and one of 2 BTC back to the sender as a new UTXO.

Answer

Bitcoin's Unspent Transaction Output (UTXO) model requires that an entire UTXO be consumed in a transaction. The outputs will consist of the payment to the recipient and the 'change' which is sent back to the sender in the form of a new UTXO. In this case, 1 BTC goes to the recipient, and the remaining 2 BTC (minus any transaction fee) goes back to the sender.

Question 3

What is the primary factor miners use to prioritize transactions for inclusion in a new block?

Accepted Answer

The transaction fee rate (satoshis per virtual byte).

Answer

Miners are economically incentivized to maximize their revenue. They do this by selecting transactions that offer the highest fee relative to their size in the block. This is measured in satoshis per virtual byte (sat/vB). A higher fee rate makes a transaction more attractive to a miner.

Question 4

Which of the following represents the first confirmation of a Bitcoin transaction?

Accepted Answer

When the transaction is included in a valid block that is added to the blockchain.

Answer

A Bitcoin transaction receives its first confirmation when it is included by a miner into a newly mined, valid block that is accepted by the network and added to the blockchain. Subsequent blocks added on top increase the number of confirmations.

Question 5

A user is trying to send a Bitcoin transaction, but it remains unconfirmed for an unusually long time during a period of high network activity. What is the most likely reason for this delay?

Accepted Answer

The transaction fee included was too low compared to other competing transactions.

Answer

During periods of high network congestion, many transactions compete for limited space in each block. Miners prioritize transactions with higher fee rates. If a transaction has a fee that is too low, it will be consistently outbid by others and will have to wait in the mempool until fees come down or it is dropped.

(CBP) Certified Bitcoin Professional Practice Test

(CBP) Certified Bitcoin Professional Practice Test

CBP - Certified Bitcoin Professional Blockchain and Transaction Mechanics Questions and Answers