Mining and Transaction Lifecycle Flashcards
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What is 'child-pays-for-parent' (CPFP) in Bitcoin?
Answer: A technique where a recipient spends an unconfirmed transaction's output with a high fee to incentivize miners to confirm both
CPFP lets a recipient create a new transaction spending the unconfirmed funds with a high fee, incentivizing miners to include both the parent and child transactions.
What is 'stratum protocol' in the context of mining pools?
Answer: A communication protocol between miners and pool servers to efficiently distribute mining work
Stratum is a lightweight protocol used by mining pools to push work to individual miners and collect submitted shares efficiently.
Which of the following correctly describes 'proof of burn' as a consensus mechanism?
Answer: Validators destroy coins by sending them to an unspendable address to earn the right to mine
Proof of burn requires participants to permanently destroy coins by sending them to a verifiably unspendable address, demonstrating commitment in exchange for mining rights.
What is a 'mining share' in the context of pool mining?
Answer: A proof of work submission that meets the pool's lower difficulty target, used to measure a miner's contribution
A share is a partial proof-of-work that satisfies the pool's easier target, allowing the pool to measure each miner's contribution before distributing block rewards proportionally.
What distinguishes a 'light client' (SPV wallet) from a full node?
Answer: Light clients download only block headers and verify transactions using Merkle proofs, without storing the full blockchain
SPV (Simplified Payment Verification) clients rely on Merkle proofs and block headers to verify transactions without downloading the full blockchain.
What is the 'extraNonce' field used for in Bitcoin mining?
Answer: To extend the search space for valid hashes beyond the 32-bit nonce limit
When the 32-bit nonce space is exhausted without finding a valid hash, miners modify the extraNonce in the coinbase transaction to create additional variation in the block header hash.
What is 'Finney attack' in cryptocurrency security?
Answer: A pre-mining attack where a miner broadcasts a block only after receiving goods from a zero-confirmation transaction
In a Finney attack, a dishonest miner pre-mines a block with a self-transfer, then quickly spends at a merchant accepting zero-confirmation payments before broadcasting the pre-mined block.