Blockchain Architecture and Its Core Components BBLC Practice Questions (Page 5)

Questions 21–25

1. 21application · medium

   A developer is explaining to a client how a blockchain ensures that a historical transaction cannot be altered without detection. The developer points to the block containing the transaction. Which property of that block is most directly responsible for this guarantee?

   • AThe block contains the hash of the previous block in its header, creating a cryptographic chain.
   • BThe block contains a digital signature from the network administrator.
   • CThe block is stored on a single server that is protected by a firewall.
   • DThe block contains a timestamp that is verified by a trusted third party.
   Reveal Solution Discussion Select an answer first
2. 22expert · hard

   A security auditor claims that a blockchain's immutability is absolute. A blockchain architect is asked to respond. Which response is most accurate?

   • AImmutability is absolute because all nodes store a copy of the ledger.
   • BImmutability is guaranteed because each block contains the hash of the previous block.
   • CImmutability is absolute only if the blockchain uses Proof of Work.
   • DImmutability is probabilistic and depends on the consensus mechanism and the cost of rewriting the chain.
   Reveal Solution Discussion Select an answer first
4. 23foundation · easy

   In a blockchain system, which architectural layer is primarily responsible for storing the actual transaction data and the linked blocks?

   • ANetwork layer
   • BData layer
   • CConsensus layer
   • DApplication layer
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5. 24application · medium

   A security auditor is evaluating a blockchain-based land registry. She wants to confirm that the system provides tamper evidence. Which combination of features provides this?

   • AA centralized database with strong encryption and a backup server.
   • BCryptographic hashes linking blocks and a distributed network of nodes that each hold a copy of the ledger.
   • CA firewall and antivirus software on the server hosting the ledger.
   • DA digital signature from the government authority on each block.
   Reveal Solution Discussion Select an answer first
6. 25application · medium

   In a peer-to-peer blockchain network, a node receives a new transaction. What is the node's primary responsibility regarding that transaction before it is included in a block?

   • AValidate the transaction's signature and format, then propagate it to its peers.
   • BStore the transaction in a private queue and wait for a central coordinator to approve it.
   • CImmediately add the transaction to its own copy of the ledger without broadcasting.
   • DEncrypt the transaction with the recipient's public key before forwarding.
   Reveal Solution Discussion Select an answer first