Blockchain Technology Core Concepts 4

Question 1

What is the UTXO model used in Bitcoin, and how does it differ from the account model used in Ethereum?

Accepted Answer

UTXO tracks unspent transaction outputs; account model tracks balances directly in named accounts

Answer

Bitcoin's UTXO model tracks individual unspent outputs as spendable inputs, while Ethereum's account model maintains a global state of balances.

Question 2

What is 'block propagation' and why does its speed matter in blockchain networks?

Accepted Answer

The time it takes for a newly mined block to reach all nodes, affecting orphan block rates

Answer

Slow block propagation increases the chance of competing miners producing orphan blocks simultaneously, wasting computational resources.

Question 3

What role does a blockchain explorer serve for end users?

Accepted Answer

It provides a searchable interface to view transactions, blocks, and wallet addresses on the blockchain

Answer

Blockchain explorers like Etherscan or Blockchain.info let users look up transaction status, wallet balances, and block details in real time.

Question 4

What is a multi-signature (multisig) transaction and what security benefit does it provide?

Accepted Answer

A transaction that requires multiple private key signatures before it can be executed

Answer

Multisig requires M-of-N designated private keys to sign a transaction, reducing single-point-of-failure risk.

Question 5

In Proof of Stake, what is 'slashing' and why is it important?

Accepted Answer

Penalizing validators who act maliciously by destroying part of their staked tokens

Answer

Slashing deters dishonest validator behavior (e.g., double-signing) by burning a portion of their staked collateral as punishment.

Blockchain Practice Test