C4 Mining & Consensus Mechanisms 2 — Questions and Answers
Question 1: In Proof of Stake, what primarily determines a validator's probability of being chosen to propose a new block?
- The validator's uptime and geographic location
- The amount of cryptocurrency staked as collateral (Correct answer)
- The validator's historical accuracy in signing previous blocks
- The processing speed of the validator's hardware
Correct answer: The amount of cryptocurrency staked as collateral
In PoS, validators are selected with probability proportional to their staked amount, replacing the computational power competition of Proof of Work.
Question 2: What is 'slashing' in Proof of Stake networks?
- Reducing transaction fees during periods of low network activity
- Cutting the block reward when a validator proposes blocks too slowly
- Penalizing validators by destroying part of their stake for malicious or dishonest behavior (Correct answer)
- Splitting a validator's stake between multiple competing candidate blocks
Correct answer: Penalizing validators by destroying part of their stake for malicious or dishonest behavior
Slashing is a penalty mechanism that destroys a portion of a misbehaving validator's staked cryptocurrency, deterring double-signing, equivocation, and other attacks.
Question 3: What is Delegated Proof of Stake (DPoS)?
- A system where mining power is delegated to cloud computing providers
- A consensus mechanism where token holders vote for delegates who validate transactions on their behalf (Correct answer)
- A model where large validators delegate block production to smaller backup nodes
- A protocol allowing validators to transfer their block production rights to other validators
Correct answer: A consensus mechanism where token holders vote for delegates who validate transactions on their behalf
DPoS allows token holders to elect a limited set of delegates (block producers) who are responsible for validating transactions, improving throughput at the cost of some decentralization.
Question 4: Which foundational computer science problem does blockchain consensus primarily aim to solve?
- The Double Spend Problem
- The Oracle Problem
- The Byzantine Generals Problem (Correct answer)
- The Halting Problem
Correct answer: The Byzantine Generals Problem
Blockchain consensus mechanisms were designed to solve the Byzantine Generals Problem — achieving reliable agreement among distributed parties who may be unreliable or actively malicious.
Question 5: What is a 51% attack?
- When 51% of users vote to alter a blockchain's protocol rules
- When a single entity controls over half the network's consensus power and can manipulate recent transactions (Correct answer)
- When a network loses 51% of its nodes due to a coordinated outage
- When 51% of a blockchain's total supply is concentrated in a single wallet
Correct answer: When a single entity controls over half the network's consensus power and can manipulate recent transactions
A 51% attack occurs when an entity gains majority control of a network's consensus power, enabling double-spending and selective transaction censorship.
Question 6: What distinguishes ASICs from GPU mining rigs in cryptocurrency mining?
- ASICs are software-based solutions while GPUs are dedicated hardware components
- ASICs are designed for general computing tasks while GPUs are optimized specifically for mining
- ASICs are purpose-built for specific algorithms and are far more power-efficient than general-purpose GPUs (Correct answer)
- ASICs can only mine Proof of Stake coins while GPUs are used exclusively for Proof of Work
Correct answer: ASICs are purpose-built for specific algorithms and are far more power-efficient than general-purpose GPUs
ASICs (Application-Specific Integrated Circuits) are custom-built chips optimized for a single mining algorithm, delivering significantly higher efficiency and hash rate than general-purpose GPUs.
Question 7: How does Bitcoin's difficulty adjustment mechanism work?
- Difficulty adjusts after every block based on the instantaneous network hash rate
- Difficulty changes are proposed by miners and voted on monthly
- Difficulty adjusts every 2,016 blocks to maintain a target average block time of 10 minutes (Correct answer)
- Difficulty increases linearly with the cumulative total supply of Bitcoin that has been mined
Correct answer: Difficulty adjusts every 2,016 blocks to maintain a target average block time of 10 minutes
Bitcoin recalibrates mining difficulty every 2,016 blocks (approximately every two weeks) to maintain the target of producing one block every 10 minutes on average.
C4 Mining & Consensus Mechanisms 2
In Proof of Stake, what primarily determines a validator's probability of being chosen to propose a new block?