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
In a Merkle tree, what is stored at each leaf node?
Answer: The hash of an individual transaction
Leaf nodes contain the hashes of individual transactions, which are then combined upward to form the Merkle root.
What property of cryptographic hash functions ensures a tiny input change produces a completely different output?
Answer: The avalanche effect
The avalanche effect means a single-bit input change cascades into a drastically different hash output.
How does a block reference the block before it in the chain?
Answer: By including the previous block's hash in its header
Each block header contains the hash of the previous block, creating an immutable cryptographic link.
What is the primary benefit of a Merkle tree for lightweight (SPV) clients?
Answer: They can verify a transaction's inclusion without downloading the full block
Merkle proofs let SPV clients confirm a transaction belongs to a block using only a small branch of hashes.
If a Merkle tree has an odd number of leaf nodes, how is this commonly handled in Bitcoin?
Answer: The last hash is duplicated to make a pair
Bitcoin duplicates the final hash when a level has an odd count so it can be paired and hashed.
What data structure is a blockchain fundamentally based on?
Answer: A hash-linked list of blocks
A blockchain is essentially a singly-linked list where each node links backward via cryptographic hashes.
Why is a blockchain considered tamper-evident?
Answer: Altering one block changes its hash and breaks all subsequent links
Changing any block's data invalidates its hash, which cascades and invalidates every later block's reference.