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Mining and Transaction Lifecycle Flashcards

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  1. What is 'Replace-By-Fee' (RBF) in Bitcoin?

    Answer: A protocol allowing an unconfirmed transaction to be replaced by a new version with a higher fee

    RBF (BIP 125) lets a sender broadcast a replacement transaction with a higher fee to incentivize miners to confirm it faster, before the original is mined.

  2. In Ethereum's proof-of-stake, what do validators stake to participate in block creation?

    Answer: 32 ETH as a deposit

    Ethereum validators must stake exactly 32 ETH to activate a validator node and participate in block proposal and attestation.

  3. What is a 'block reward subsidy' in Bitcoin?

    Answer: The fixed amount of new Bitcoin created and given to the miner per block

    The block subsidy is the newly minted Bitcoin awarded to the miner who successfully adds a block; it halves approximately every four years.

  4. What is 'transaction malleability' in the context of Bitcoin?

    Answer: The ability to alter a transaction's ID without invalidating its signature, before confirmation

    Transaction malleability allowed the transaction ID (txid) to be changed by modifying the unlocking script before confirmation, a flaw addressed by SegWit.

  5. What does 'hashrate' measure in cryptocurrency mining?

    Answer: The speed at which a miner performs hash computations per second

    Hashrate measures how many hash calculations a mining device or network performs per second, indicating mining power and network security.

  6. What is the purpose of a 'checkpoint' in some cryptocurrency implementations?

    Answer: To hardcode specific block hashes into the software to prevent deep chain reorganizations

    Checkpoints are hardcoded block hashes in node software that prevent the chain from being reorganized below that point, protecting against history-rewriting attacks.

  7. During a Bitcoin transaction, what is the 'change output'?

    Answer: The unspent portion of input UTXOs sent back to the sender's wallet

    Since UTXOs must be spent entirely, any excess value beyond the intended payment and fees is returned to the sender as a change output.