CBSA Core Blockchain Principles 3

Question 1

What problem does the Byzantine Generals Problem illustrate in the context of distributed blockchain networks?

Accepted Answer

How to reach consensus among nodes when some may act maliciously or fail

Answer

How to encrypt messages between nodes

Answer

How to partition data across geographic regions

Answer

How to reduce transaction fees

Question 2

What is a '51% attack' in a Proof of Work blockchain?

Accepted Answer

When an entity controls more than half the network's hash rate, enabling double-spend attacks

Answer

When 51 validators simultaneously go offline

Answer

When transaction fees exceed 51% of block reward

Answer

When 51% of nodes reject a software upgrade

Question 3

In Ethereum's account model, what is the difference between an Externally Owned Account (EOA) and a Contract Account?

Accepted Answer

EOAs are controlled by private keys; Contract Accounts are controlled by smart contract code

Answer

EOAs hold Ether only; Contract Accounts hold tokens only

Answer

EOAs require gas; Contract Accounts do not

Answer

EOAs are on-chain; Contract Accounts are off-chain

Question 4

What does 'gas' represent in the Ethereum blockchain?

Accepted Answer

A unit measuring computational effort required to execute operations

Answer

A native cryptocurrency pegged to natural gas prices

Answer

The number of validators approving a transaction

Answer

The storage space allocated per block

Question 5

Which consensus mechanism selects block validators based on the amount of cryptocurrency they lock up as collateral?

Accepted Answer

Proof of Stake

Answer

Proof of Work

Answer

Proof of Authority

Answer

Delegated Proof of History

Question 6

What is the significance of the Genesis Block in a blockchain?

Accepted Answer

It is the first block with no predecessor, hardcoded into the protocol

Answer

It contains the largest transaction volume

Answer

It is regenerated daily to reset difficulty

Answer

It stores validator identities

Question 7

What is 'sharding' designed to solve in blockchain architecture?

Accepted Answer

Scalability by partitioning the network into smaller parallel-processing segments

Answer

Private key management complexity

Answer

Cross-chain interoperability

Answer

Smart contract vulnerability detection