Blockchain Architecture and Its Core Components BBLC Practice Questions (Page 10)

Questions 46–50

1. 46expert · hard

   A government agency is considering a blockchain for public records. They have two requirements: (1) the data must be tamper-evident, and (2) the system must be resilient to the failure of any single node. Which architecture best satisfies both?

   • AA public blockchain with no access control.
   • BA single-node blockchain with a backup server.
   • CA permissioned blockchain with multiple nodes operated by different government departments, using a consensus mechanism like PBFT.
   • DA centralized database with cryptographic signatures on each record.
   Reveal Solution Discussion Select an answer first
2. 47application · medium

   A company wants to use a smart contract to manage a loyalty points program. They are concerned about the security of the contract. What is a key characteristic of smart contract execution that they should be aware of?

   • ASmart contracts are stored off-chain and executed on a trusted server.
   • BSmart contract code is immutable once deployed, so bugs cannot be fixed by simply updating the code.
   • CSmart contracts can be paused and edited by the network administrator at any time.
   • DSmart contracts are executed only once by the deploying organization.
   Reveal Solution Discussion Select an answer first
4. 48expert · hard

   A blockchain network is experiencing delayed transaction propagation. The network uses a peer-to-peer gossip protocol. Which change is most likely to improve propagation speed?

   • ASwitch to a centralized server for transaction distribution.
   • BIncrease the number of peer connections each node maintains.
   • CIncrease the difficulty of the consensus algorithm.
   • DReduce the block size to allow more blocks per second.
   Reveal Solution Discussion Select an answer first
5. 49application · medium

   A consortium of banks is evaluating a distributed ledger to share transaction data. They require that no single bank controls the ledger and that each bank can independently verify the data. Which architectural feature of DLT directly satisfies this requirement?

   • AThe ledger is stored in a shared cloud database with read-only access for all banks.
   • BA central coordinator node is elected to approve all transactions and distribute the ledger to other banks.
   • CEach bank runs a node that maintains a full copy of the ledger and participates in consensus.
   • DEach bank maintains its own private ledger and periodically reconciles with others.
   Reveal Solution Discussion Select an answer first
6. 50expert · hard

   A blockchain network uses Proof of Work. An attacker controls 40% of the total hash rate. Which attack is the attacker most likely able to perform?

   • ATemporarily prevent new transactions from being confirmed by mining empty blocks or ignoring specific transactions.
   • BModify historical blocks without detection.
   • CReverse confirmed transactions and double-spend with certainty.
   • DSteal funds from other users' wallets.
   Reveal Solution Discussion Select an answer first