CBP - Certified Bitcoin Professional Forks and Network Upgrades Questions and Answers

Question 1

What is the fundamental distinction between a hard fork and a soft fork in the context of Bitcoin network upgrades?

Accepted Answer

A soft fork tightens consensus rules and is backward-compatible, while a hard fork changes rules in a non-backward-compatible way.

Answer

A soft fork is a temporary chain split, while a hard fork is permanent.

Answer

A hard fork requires a majority of miners to upgrade, while a soft fork requires a majority of users.

Answer

Soft forks are for minor bug fixes, whereas hard forks are for major feature additions.

Question 2

The Segregated Witness (SegWit) upgrade was implemented as a soft fork. How did this implementation method allow the network to upgrade without forcing all nodes to update their software immediately?

Accepted Answer

The witness data was structured in a way that older nodes would see the transactions as valid, even though they couldn't fully interpret the new data. [8, 15]

Answer

It created a separate, optional blockchain for SegWit transactions that older nodes could ignore.

Answer

It required all miners to signal support, which automatically pushed the update to all nodes.

Answer

It was implemented via a hard fork but was called a soft fork for political reasons.

Question 3

In 2017, a contentious hard fork resulted in the creation of Bitcoin Cash (BCH). Which of the following was a direct and immediate consequence for users who held Bitcoin at the time of the fork?

Accepted Answer

They ended up holding an equal amount of coins on both the BTC and BCH chains, as the transaction history was duplicated up to the point of the split.

Answer

Their BTC was automatically converted to BCH on the new chain.

Answer

They were required to choose which chain to support, forfeiting their coins on the other.

Answer

All transaction history was erased on the new BCH chain to provide a clean start.

Question 4

Which of the following represents the most significant risk associated with implementing a non-unanimous hard fork on the Bitcoin network?

Accepted Answer

A permanent chain split if there is not overwhelming consensus, leading to two competing cryptocurrencies.

Answer

A temporary decrease in transaction fees.

Answer

The requirement for all users to generate new private keys.

Answer

An automatic increase in the block size limit.

Question 5

A Bitcoin Improvement Proposal (BIP) suggests a new feature to be activated as a soft fork using a miner-signaling mechanism like BIP 9. What does it mean when miners "signal" for the upgrade?

Accepted Answer

They include specific data (a version bit) in the headers of the blocks they mine to indicate their readiness for the new rules.

Answer

They send a special transaction to a designated address to cast their vote.

Answer

They verbally agree to the change in public forums and developer mailing lists.

Answer

They stop mining blocks until the new rules are officially accepted by all major exchanges.

Question 6

A new soft fork upgrade is scheduled to activate on the Bitcoin network. As an operator of a non-mining full node, what is the primary consequence of choosing NOT to upgrade your software?

Accepted Answer

Your node will continue to operate but will have a less secure or complete view of the blockchain's state, as it cannot fully validate the new rules.

Answer

Your node will be banned from the network and will stop receiving any new blocks.

Answer

Your node will automatically reject all transactions, both old and new, until it is upgraded.

Answer

Your node will cause a hard fork because it is enforcing the old rules.