Core Concepts 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 Concepts flashcards as text
What property ensures that once a block is added to a blockchain, its data cannot be altered without changing all subsequent blocks?
Answer: Immutability
Immutability is the property that makes blockchain data tamper-resistant, since each block's hash depends on the previous block's data.
In a Merkle tree structure used in blockchain, what does the root hash represent?
Answer: A single fingerprint of all transactions in a block
The Merkle root is a single hash derived from hashing all transactions in pairs recursively, summarizing the entire transaction set.
Which type of blockchain network restricts participation to pre-approved entities?
Answer: Permissioned blockchain
Permissioned (or private) blockchains require participants to be authorized before joining the network.
What is a 'genesis block' in blockchain terminology?
Answer: The first block in a blockchain
The genesis block is the very first block in a blockchain, hard-coded with no previous block reference.
What does the nonce field in a block header primarily serve in Proof of Work?
Answer: It is a number miners adjust to find a valid hash below the difficulty target
Miners increment the nonce repeatedly until the resulting block hash meets the required difficulty target.
How does a blockchain network achieve fault tolerance against Byzantine failures?
Answer: Through consensus mechanisms that require agreement among a majority of nodes
Byzantine Fault Tolerant consensus algorithms allow the network to reach agreement even if some nodes behave maliciously or fail.
What distinguishes a hard fork from a soft fork in blockchain protocol upgrades?
Answer: A hard fork is backward-incompatible, creating a permanent chain split if not universally adopted
A hard fork introduces protocol changes that old nodes cannot validate, potentially creating two separate chains if adoption is split.