CBP Bitcoin Mining and Consensus Mechanisms 4

Question 1

What is 'merge mining' (AuxPoW) in the Bitcoin ecosystem?

Accepted Answer

Mining a secondary blockchain using Bitcoin's proof-of-work with no extra computation

Answer

Merge mining (Auxiliary Proof of Work) allows miners to submit Bitcoin's proof-of-work as valid proof for another blockchain that has adopted the same algorithm, at no additional computational cost.

Question 2

What is the maximum size of the nonce field in a Bitcoin block header?

Accepted Answer

32 bits

Answer

The nonce is a 32-bit (4-byte) field in the block header, providing 2^32 (about 4.3 billion) possible values.

Question 3

What is a '51% attack' on the Bitcoin network?

Accepted Answer

An entity controlling majority hashrate double-spends coins by rewriting recent history

Answer

With over 50% of the network's hashrate, an attacker can mine a longer private chain to reverse recently confirmed transactions and double-spend bitcoin.

Question 4

What does the 'bits' field in a Bitcoin block header represent?

Accepted Answer

The current difficulty target encoded in compact 4-byte format

Answer

The 'bits' field is a compact encoding of the 256-bit difficulty target that a valid block hash must be less than or equal to.

Question 5

Why is Bitcoin's Proof of Work considered 'Nakamoto consensus'?

Accepted Answer

Because it achieves agreement probabilistically through the longest valid chain rule without trusted parties

Answer

Nakamoto consensus achieves decentralized agreement by having all nodes follow the chain with the most cumulative proof of work, without any central coordinator.

(CBP) Certified Bitcoin Professional Practice Test

(CBP) Certified Bitcoin Professional Practice Test

CBP Bitcoin Mining and Consensus Mechanisms 4