Bitcoin Network and Its Transactions BDC Practice Questions (Page 7)

Questions 31–35

1. 31application · medium

   A developer is designing a payment system that must prevent double-spending without relying on a central authority. The system uses a UTXO model. Which property of the UTXO model is essential for this requirement?

   • AEach UTXO is associated with a private key that is stored on a central server.
   • BEach transaction must be approved by a majority of nodes before it is broadcast.
   • CEach UTXO can be spent only once, and the transaction that spends it is recorded in the blockchain.
   • DEach transaction must include a timestamp that is verified by a trusted third party.
   Reveal Solution Discussion Select an answer first
2. 32foundation · easy

   What is the purpose of the locking script (scriptPubKey) in a Bitcoin transaction output?

   • ATo encrypt the transaction data for privacy
   • BTo record the transaction fee paid to miners
   • CTo store the digital signature of the sender
   • DTo specify the conditions under which the output can be spent
   Reveal Solution Discussion Select an answer first
4. 33application · medium

   A developer is setting up a Bitcoin node for a research project. The node must be able to query the balance of any address at any point in history. Which type of node is required?

   • AA pruned full node that stores only recent blocks.
   • BAn archival full node that stores the entire blockchain from genesis.
   • CA lightweight SPV node that stores block headers.
   • DA mining node that only stores the UTXO set.
   Reveal Solution Discussion Select an answer first
5. 34foundation · easy

   How does the UTXO model help prevent double-spending?

   • ABy encrypting all transactions with a shared secret key
   • BBy requiring every transaction to be approved by a central authority
   • CBy limiting the number of transactions per block
   • DBy ensuring that each UTXO can only be used as an input once
   Reveal Solution Discussion Select an answer first
6. 35application · medium

   A company wants to run a Bitcoin node to support its payment processing. The node must validate transactions and blocks independently without relying on third-party APIs. Which type of node should they run?

   • AA lightweight SPV node that only downloads block headers.
   • BAn archival node that stores the entire blockchain but does not validate new transactions.
   • CA full node that downloads and validates the entire blockchain.
   • DA mining node that only validates blocks it attempts to mine.
   Reveal Solution Discussion Select an answer first