CBSA Core Blockchain Principles 3 — Questions and Answers
Question 1: What problem does the Byzantine Generals Problem illustrate in the context of distributed blockchain networks?
- How to encrypt messages between nodes
- How to reach consensus among nodes when some may act maliciously or fail (Correct answer)
- How to partition data across geographic regions
- How to reduce transaction fees
Correct answer: How to reach consensus among nodes when some may act maliciously or fail
The Byzantine Generals Problem models the challenge of achieving reliable agreement in a distributed system where some participants may send conflicting or false information.
Question 2: What is a '51% attack' in a Proof of Work blockchain?
- When 51 validators simultaneously go offline
- When an entity controls more than half the network's hash rate, enabling double-spend attacks (Correct answer)
- When transaction fees exceed 51% of block reward
- When 51% of nodes reject a software upgrade
Correct answer: When an entity controls more than half the network's hash rate, enabling double-spend attacks
Controlling majority hash power lets an attacker secretly mine an alternate chain, enabling them to reverse transactions and double-spend.
Question 3: In Ethereum's account model, what is the difference between an Externally Owned Account (EOA) and a Contract Account?
- EOAs hold Ether only; Contract Accounts hold tokens only
- EOAs are controlled by private keys; Contract Accounts are controlled by smart contract code (Correct answer)
- EOAs require gas; Contract Accounts do not
- EOAs are on-chain; Contract Accounts are off-chain
Correct answer: EOAs are controlled by private keys; Contract Accounts are controlled by smart contract code
EOAs are managed by users with private keys and can initiate transactions, while Contract Accounts execute predefined code when triggered by transactions.
Question 4: What does 'gas' represent in the Ethereum blockchain?
- A native cryptocurrency pegged to natural gas prices
- A unit measuring computational effort required to execute operations (Correct answer)
- The number of validators approving a transaction
- The storage space allocated per block
Correct answer: A unit measuring computational effort required to execute operations
Gas quantifies the computational work required for each operation, and users pay gas fees to incentivize validators to include their transactions.
Question 5: Which consensus mechanism selects block validators based on the amount of cryptocurrency they lock up as collateral?
- Proof of Work
- Proof of Stake (Correct answer)
- Proof of Authority
- Delegated Proof of History
Correct answer: Proof of Stake
Proof of Stake selects validators proportional to their staked collateral, replacing energy-intensive hash computation with economic stake.
Question 6: What is the significance of the Genesis Block in a blockchain?
- It contains the largest transaction volume
- It is the first block with no predecessor, hardcoded into the protocol (Correct answer)
- It is regenerated daily to reset difficulty
- It stores validator identities
Correct answer: It is the first block with no predecessor, hardcoded into the protocol
The Genesis Block (Block 0) is the foundation of the entire chain; it has no parent hash and its values are hardcoded into the client software.
Question 7: What is 'sharding' designed to solve in blockchain architecture?
- Private key management complexity
- Scalability by partitioning the network into smaller parallel-processing segments (Correct answer)
- Cross-chain interoperability
- Smart contract vulnerability detection
Correct answer: Scalability by partitioning the network into smaller parallel-processing segments
Sharding splits the blockchain into smaller shards that process transactions in parallel, increasing overall network throughput.
CBSA Core Blockchain Principles 3
What problem does the Byzantine Generals Problem illustrate in the context of distributed blockchain networks?