Blockchain Technology Fundamentals Flashcards
7 cards from real Cryptocurrency practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Blockchain Technology Fundamentals flashcards as text
What is the Byzantine Generals Problem in relation to blockchain?
Answer: The challenge of reaching consensus among distributed nodes that may be dishonest
The Byzantine Generals Problem describes how decentralized systems must reach reliable consensus even when some participants send conflicting or malicious messages.
What is the UTXO model used in Bitcoin?
Answer: A model where transactions consume previous outputs and create new unspent outputs
The Unspent Transaction Output model treats coins as discrete outputs; a transaction spends existing UTXOs as inputs and creates new UTXOs, with no global account balance.
What is 'double spending' and why is preventing it critical to cryptocurrencies?
Answer: Using the same digital coins in two transactions simultaneously, undermining monetary value
Double spending is the digital equivalent of counterfeiting; blockchain consensus prevents it by ensuring only one version of a transaction history is accepted network-wide.
What is 'block propagation' in a blockchain network?
Answer: The speed at which a newly mined block spreads to all nodes in the network
Fast block propagation reduces the chance of orphaned blocks and chain splits; slow propagation gives large mining pools a centralization advantage.
What does 'gas' represent on the Ethereum blockchain?
Answer: A unit measuring the computational effort required to execute an operation
Gas quantifies computation on Ethereum; each operation (e.g., addition, storage write) has a fixed gas cost, and users pay gas_used × gas_price in ETH to compensate validators.
What is a 'sidechain' in blockchain architecture?
Answer: A separate blockchain that runs in parallel and is pegged to a main chain
Sidechains allow assets to be transferred from a main chain via a two-way peg, enabling experimentation or specialized functionality without burdening the main chain.
What is the purpose of a blockchain 'mempool'?
Answer: A holding area for unconfirmed transactions waiting to be included in a block
The memory pool (mempool) is where broadcast transactions queue before miners/validators select them for block inclusion, typically prioritizing higher-fee transactions.