CCE Blockchain Fundamentals 2 — Questions and Answers
Question 1: What is the primary purpose of a Merkle tree in blockchain architecture?
- To store transaction metadata in plaintext
- To efficiently verify the integrity of large datasets (Correct answer)
- To encrypt wallet private keys
- To assign block rewards to miners
Correct answer: To efficiently verify the integrity of large datasets
Merkle trees allow any transaction in a block to be verified by checking only a logarithmic number of hashes rather than the entire dataset.
Question 2: Which characteristic best describes a 'permissioned' blockchain?
- Anyone can read and write without restriction
- Participation requires authorization from a governing entity (Correct answer)
- Consensus is always achieved via proof-of-work
- All nodes must hold an equal stake in the network
Correct answer: Participation requires authorization from a governing entity
Permissioned blockchains restrict who can join and transact, making them common in enterprise and consortium settings.
Question 3: In blockchain terminology, what is a 'genesis block'?
- The block with the highest transaction volume
- The block that closes a difficulty epoch
- The very first block in a blockchain (Correct answer)
- A block that contains only coinbase transactions
Correct answer: The very first block in a blockchain
The genesis block (block 0) is hard-coded as the starting point of a blockchain with no predecessor hash.
Question 4: What does 'block finality' mean in the context of blockchain?
- A block's hash meets the current difficulty target
- A confirmed block can never be reversed or altered (Correct answer)
- The last block in a chain before a scheduled hard fork
- A block that holds the maximum allowed transaction count
Correct answer: A confirmed block can never be reversed or altered
Finality guarantees that once a block is confirmed, its transactions are irreversible and permanently part of the ledger.
Question 5: How does a hard fork differ from a soft fork?
- A hard fork only affects mining nodes while a soft fork affects all nodes
- A hard fork is backward-compatible; a soft fork is not
- A hard fork creates a permanent chain split; a soft fork remains backward-compatible (Correct answer)
- Hard forks require miner approval; soft forks require user approval
Correct answer: A hard fork creates a permanent chain split; a soft fork remains backward-compatible
A hard fork introduces protocol changes that non-upgraded nodes cannot follow, potentially creating two separate chains, while a soft fork is backward-compatible.
Question 6: What role does a 'full node' play in a blockchain network?
- It only downloads block headers to verify transactions
- It stores a complete copy of the blockchain and independently validates all rules (Correct answer)
- It exclusively produces new blocks through mining
- It routes transactions between wallets without storing data
Correct answer: It stores a complete copy of the blockchain and independently validates all rules
Full nodes store the entire blockchain history and enforce all consensus rules, providing maximum trustlessness and security.
Question 7: What is the significance of the 'nonce' field in a blockchain block header?
- It identifies the miner's wallet address
- It records the total fees collected in the block
- It is a number miners adjust to find a valid proof-of-work hash (Correct answer)
- It specifies the block's position in the chain
Correct answer: It is a number miners adjust to find a valid proof-of-work hash
Miners iterate the nonce value until the block hash falls below the network's current difficulty target, proving computational work.
CCE Blockchain Fundamentals 2
What is the primary purpose of a Merkle tree in blockchain architecture?