Core Blockchain Data Structures Flashcards
7 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Core Blockchain Data Structures flashcards as text
What happens to the Merkle root if a single transaction in the block is modified?
Answer: The Merkle root changes completely
Because the root is derived from all leaves, modifying any transaction propagates a new root value.
Which hash algorithm does Bitcoin primarily use for block hashing?
Answer: SHA-256
Bitcoin uses double SHA-256 for block and transaction hashing.
What is the role of the nonce in a block header?
Answer: A value miners adjust to find a valid proof-of-work hash
The nonce is varied during mining to produce a header hash meeting the difficulty target.
Compared to a list, why is a Merkle tree more efficient for verifying data integrity?
Answer: It allows verifying a subset without rehashing all data
A Merkle tree enables verifying individual items with a short proof rather than rehashing the entire dataset.
What is an 'uncle' (ommer) block reference in some blockchain data models?
Answer: A valid block not on the main chain but referenced for partial reward
Uncle/ommer blocks are valid stale blocks referenced by the main chain, historically rewarding their miners.
What guarantees immutability in a hash-linked chain of blocks?
Answer: Each block's hash depends on its content and the prior block's hash
Content-dependent hashing chained backward means any change breaks every subsequent link, enforcing immutability.
How are transactions ordered within a block's Merkle tree construction?
Answer: In a defined, deterministic order so the root is reproducible
Transactions follow a deterministic order so any node rebuilding the tree computes the identical Merkle root.