Blockchain Technology Architecture and Platforms 4 — Questions and Answers
Question 1: What problem does the Lightning Network solve for Bitcoin?
- It increases Bitcoin's block size to 10MB
- It enables fast, low-cost off-chain payments through bidirectional payment channels (Correct answer)
- It adds smart contract functionality to Bitcoin
- It reduces Bitcoin's mining difficulty
Correct answer: It enables fast, low-cost off-chain payments through bidirectional payment channels
The Lightning Network creates bidirectional payment channels between users so that multiple transactions can occur off-chain, settling only the final balance on Bitcoin's blockchain.
Question 2: What is a 'fork' in blockchain, and what distinguishes a hard fork from a soft fork?
- Both are network attacks; hard forks are more severe
- A hard fork creates an incompatible protocol change requiring all nodes to upgrade, while a soft fork is backward-compatible (Correct answer)
- A soft fork splits the chain permanently; a hard fork does not
- Hard forks are temporary; soft forks are permanent
Correct answer: A hard fork creates an incompatible protocol change requiring all nodes to upgrade, while a soft fork is backward-compatible
A hard fork introduces rule changes that make old nodes incompatible, potentially splitting the chain, while a soft fork tightens rules in a backward-compatible way.
Question 3: What is 'chain reorganization' (reorg) in a blockchain network?
- A planned protocol upgrade to restructure the block format
- When a longer competing chain causes the network to replace a portion of the canonical chain (Correct answer)
- The process of archiving old blocks to free storage
- A governance vote to rearrange validator ordering
Correct answer: When a longer competing chain causes the network to replace a portion of the canonical chain
A chain reorganization occurs when a newly discovered chain with more cumulative work (or stake) replaces the current canonical chain, reverting recent blocks.
Question 4: Which architectural pattern does Cosmos use to achieve blockchain interoperability?
- Merged mining across all chains
- The Inter-Blockchain Communication (IBC) protocol connecting sovereign chains via hubs (Correct answer)
- A single relay chain with parachain slots
- Cross-chain atomic swaps only
Correct answer: The Inter-Blockchain Communication (IBC) protocol connecting sovereign chains via hubs
Cosmos uses the Inter-Blockchain Communication (IBC) protocol to allow independent blockchains (zones) to transfer tokens and data through hub blockchains.
Question 5: What is an 'oracle' in the context of smart contract architecture?
- A node that has full governance rights over a blockchain
- A service that provides off-chain real-world data to on-chain smart contracts (Correct answer)
- A cryptographic algorithm for key generation
- A type of wallet for storing NFTs
Correct answer: A service that provides off-chain real-world data to on-chain smart contracts
Oracles bridge the gap between blockchains and the external world by feeding real-world data (prices, weather, sports results) to smart contracts that cannot access it natively.
Question 6: What is the purpose of a Merkle tree in blockchain architecture?
- To encrypt private keys for wallet security
- To efficiently and securely verify the inclusion of transactions within a block (Correct answer)
- To calculate mining difficulty adjustments
- To manage smart contract state variables
Correct answer: To efficiently and securely verify the inclusion of transactions within a block
A Merkle tree hashes transactions pairwise up to a root hash (Merkle root), stored in the block header, enabling efficient proof that a specific transaction is included without downloading all data.
Question 7: What is the key architectural difference between account-based blockchains and UTXO-based blockchains?
- Account-based models use smart contracts; UTXO models cannot
- Account-based models track balances in accounts like a bank, while UTXO models track unspent outputs from previous transactions (Correct answer)
- UTXO models require more computational power than account models
- Account-based models are always permissioned; UTXO models are always permissionless
Correct answer: Account-based models track balances in accounts like a bank, while UTXO models track unspent outputs from previous transactions
UTXO (Unspent Transaction Output) models like Bitcoin track discrete coins from prior transactions, while account models like Ethereum maintain running balances per address.
Blockchain Technology Architecture and Platforms 4
What problem does the Lightning Network solve for Bitcoin?