CBCP Blockchain Fundamental 4

Question 1

In blockchain, what is a 'mempool' (memory pool)?

Accepted Answer

A holding area where unconfirmed transactions wait to be included in a block

Answer

The mempool is each node's local buffer of broadcast transactions awaiting confirmation; miners select transactions from it to fill new blocks.

Question 2

What property ensures that a blockchain transaction cannot be denied or reversed by the sender after it is confirmed?

Accepted Answer

Non-repudiation

Answer

Non-repudiation, enforced by digital signatures and immutable ledger records, means a sender cannot later claim they did not authorize a transaction.

Question 3

What is a '51% attack' and why does it threaten blockchain security?

Accepted Answer

When a single entity controls more than half of the network's consensus power, enabling double-spends

Answer

Controlling >50% of hash rate (PoW) or stake (PoS) lets an attacker rewrite recent history and double-spend coins on that chain.

Question 4

Which component of asymmetric cryptography is used to verify a blockchain transaction's digital signature?

Accepted Answer

The sender's public key

Answer

Anyone can use the sender's public key to verify that the signature was created by the corresponding private key, confirming authenticity without exposing the private key.

Question 5

What does 'finality' mean in the context of blockchain consensus?

Accepted Answer

The guarantee that a confirmed transaction cannot be reversed

Answer

Finality describes the point at which a transaction is considered irreversibly settled; different consensus mechanisms offer probabilistic or absolute finality.

CBCP - Certified Blockchain Professional Practice Test

CBCP - Certified Blockchain Professional Practice Test

CBCP Blockchain Fundamental 4