CBSA Consensus Mechanisms 4

Question 1

In Ethereum's Proof of Stake, what is the consequence of a validator performing a 'slashable offense' such as double voting?

Accepted Answer

A portion of the validator's staked ETH is burned and they are ejected

Answer

Slashing penalizes validators for equivocation or surround voting by destroying part of their stake and forcibly removing them from the validator set to deter attacks.

Question 2

Which of the following best describes a '51% attack' in a Proof of Work blockchain?

Accepted Answer

An attacker controls the majority of hash rate and can rewrite recent transaction history

Answer

A 51% attack occurs when a single entity controls more than half the network's computational power, enabling them to mine a longer private chain and double-spend by reorganizing blocks.

Question 3

What is the significance of the 'difficulty adjustment' algorithm in Bitcoin's Proof of Work consensus?

Accepted Answer

It recalibrates mining difficulty every 2016 blocks to target a ~10-minute block time

Answer

Bitcoin recalculates mining difficulty every 2016 blocks (~2 weeks) so that blocks are produced approximately every 10 minutes regardless of total network hash rate changes.

Question 4

In the context of consensus mechanisms, what does 'fork choice rule' determine?

Accepted Answer

How nodes select the canonical chain when multiple valid chain branches exist

Answer

The fork choice rule defines which chain branch a node considers canonical—Bitcoin uses the heaviest chain (most work), while Ethereum PoS uses LMD-GHOST.

Question 5

Algorand's Pure Proof of Stake consensus uses cryptographic sortition to select committee members. What is the key advantage of this approach?

Accepted Answer

Selection is private and non-interactive, preventing targeted attacks on future committee members

Answer

Algorand's VRF-based sortition allows each user to privately and locally determine if they are selected, so potential committee members are unknown to attackers until they reveal their selection.

(CBSA) Certified Blockchain Solution Architect Practice Test

(CBSA) Certified Blockchain Solution Architect Practice Test

CBSA Consensus Mechanisms 4