Blockchain Technology Concepts and Distributed Ledger Technology (DLT) BDC Practice Questions (Page 3)

Questions 11–15

1. 11foundation · easy

   What is the main advantage of removing a central authority in a blockchain network?

   • AIt reduces the risk of a single point of failure and gives control to the network participants.
   • BIt allows the network to operate without any rules or protocols.
   • CIt eliminates the need for any form of data validation.
   • DIt ensures that all transactions are approved by a majority of users.
   Reveal Solution Discussion Select an answer first
2. 12application · medium

   A developer is implementing a lightweight client for a blockchain that only downloads block headers, not full transactions. To verify that a specific transaction is included in a block, the client requests a proof from a full node. Which cryptographic structure does the client use to verify this proof?

   • AThe transaction's hash compared to the block's previous hash
   • BMerkle proof using the block's Merkle root
   • CDigital signature from the full node attesting to the transaction's inclusion
   • DThe full node's certificate revocation list
   Reveal Solution Discussion Select an answer first
4. 13application · medium

   A startup wants to create a decentralized marketplace where buyers and sellers can transact without a central platform operator. They plan to use a public blockchain. What is the primary mechanism that allows the network to reach agreement on the state of transactions without a central authority?

   • AA central server that validates all transactions and broadcasts the results.
   • BA random node selected by the platform operator to confirm each transaction.
   • CConsensus among distributed nodes, such as proof of work or proof of stake.
   • DA legal agreement signed by all participants to follow the platform's rules.
   Reveal Solution Discussion Select an answer first
5. 14application · medium

   A pharmaceutical company wants to track the movement of temperature-sensitive vaccines from manufacturing to administration, ensuring that each handoff is recorded and that no party can alter the history. Which blockchain use case best matches this requirement?

   • AA decentralized identity system for patients to prove their vaccination status.
   • BA cryptocurrency payment system to pay each party automatically upon delivery.
   • CA smart contract that automatically reorders vaccines when stock is low.
   • DSupply chain provenance tracking with a permissioned blockchain shared among manufacturers, distributors, and clinics.
   Reveal Solution Discussion Select an answer first
6. 15application · medium

   A blockchain developer is explaining to a client why it is extremely difficult to alter a transaction that was confirmed several blocks ago. Which combination of features provides this protection?

   • ACryptographic hashes linking each block to the previous one, plus the requirement to redo the proof-of-work for all subsequent blocks
   • BEncryption of the entire ledger with a symmetric key held by the network administrator
   • CDigital signatures on each transaction plus a timestamp from a trusted third party
   • DA central authority that reviews and approves all changes to historical blocks
   Reveal Solution Discussion Select an answer first