CBSA Core Blockchain Principles 5

Question 1

What is a 'double-spend attack' and how does blockchain consensus prevent it?

Accepted Answer

Attempting to spend the same digital asset twice; prevented by network-wide consensus validating transaction order

Answer

Paying twice the required gas fee; prevented by fee caps

Answer

Deploying two identical smart contracts; prevented by address uniqueness

Answer

Mining two blocks simultaneously; prevented by difficulty adjustment

Question 2

In the context of blockchain scalability, what is a 'Layer 2 solution'?

Accepted Answer

A protocol built on top of a base blockchain that processes transactions off-chain and settles results on-chain

Answer

A second blockchain running in parallel with no connection to Layer 1

Answer

A hardware acceleration layer for mining

Answer

A regulatory compliance layer added by governments

Question 3

What is 'chain reorganization' (reorg) and when does it occur?

Accepted Answer

A network event where a longer competing chain replaces the current canonical chain

Answer

Manual reordering of transactions by miners for profit

Answer

Scheduled block number resets for protocol upgrades

Answer

Compressing old blocks to save storage space

Question 4

Which feature of zero-knowledge proofs makes them valuable for blockchain privacy solutions?

Accepted Answer

They allow one party to prove knowledge of information without revealing the information itself

Answer

They delete transaction history after verification

Answer

They prevent validators from reading transaction amounts

Answer

They encrypt the entire blockchain ledger

Question 5

What is the purpose of a 'mempool' (memory pool) in a blockchain network?

Accepted Answer

A temporary holding area for broadcast but unconfirmed transactions awaiting inclusion in a block

Answer

Long-term archival storage for confirmed blocks

Answer

RAM allocated to running smart contracts

Answer

A cache storing the UTXO set

Question 6

In a Delegated Proof of Stake (DPoS) system, what role do 'delegates' or 'witnesses' play?

Accepted Answer

They are elected representatives who produce blocks on behalf of token holders who voted for them

Answer

They audit smart contract code before deployment

Answer

They bridge assets between different blockchain networks

Answer

They manage private key recovery for lost wallets

Question 7

What is 'interoperability' in blockchain architecture and why is it a design challenge?

Accepted Answer

The capacity for different blockchain networks to communicate, share data, and transfer assets across chains

Answer

The ability of a blockchain to run on multiple operating systems

Answer

Ensuring smart contracts work on both testnet and mainnet

Answer

Making blockchain data readable by traditional databases