Smart Contracts and dApp Design for Business BBLC Practice Questions (Page 6)

Questions 26–30

1. 26application · medium

   A company is developing a dApp for supply chain tracking. The frontend needs to display real-time shipment status to warehouse staff. The backend uses a smart contract to record shipment events. What is the most efficient way for the frontend to retrieve the latest shipment status without overwhelming the Ethereum network?

   • AUse a centralized server to directly modify the smart contract state and then serve the data.
   • BUse an off-chain indexer or event listener to maintain a local database that the frontend queries.
   • CStore all shipment data on-chain and have the frontend read the entire state on each load.
   • DHave the frontend call a view function on the smart contract for every status refresh.
   Reveal Solution Discussion Select an answer first
2. 27application · medium

   A healthcare startup is building a dApp for patients to manage consent for sharing medical records. The dApp must be easy for patients to use, but also ensure that consent is recorded immutably. What architecture should they use?

   • AA centralized database that stores consent and periodically syncs to the blockchain.
   • BA mobile app that directly interacts with the smart contract using the patient's private key stored on the device.
   • CA web interface that uses a custodial wallet managed by the healthcare provider, with the smart contract recording consent on-chain.
   • DA smart contract that stores the full medical records on-chain.
   Reveal Solution Discussion Select an answer first
4. 28application · medium

   A crowdfunding platform wants to use a smart contract to hold funds until a project reaches its funding goal. If the goal is not met, contributors should be able to get their money back. Which design pattern is most appropriate?

   • AA withdrawal pattern where each contributor can withdraw their own funds if the goal is not met.
   • BA time-locked contract that releases funds to the project owner after a fixed period.
   • CA push payment pattern where the contract automatically sends refunds to all contributors.
   • DA multi-signature wallet where the project owner approves refunds.
   Reveal Solution Discussion Select an answer first
5. 29expert · hard

   A supply chain consortium is deploying a dApp for tracking goods. The business users expect fast transaction finality and low costs. The consortium members are known and trusted. Which deployment approach best balances these needs?

   • ADeploy on a private permissioned Ethereum network with a small set of known validators.
   • BDeploy on a sidechain with no connection to the mainnet, ignoring security risks.
   • CDeploy on the Ethereum mainnet to ensure maximum decentralization and security.
   • DDeploy on a public testnet to avoid costs, but with no guarantee of availability.
   Reveal Solution Discussion Select an answer first
6. 30expert · hard

   A startup is building a dApp for decentralized identity management. The team wants to minimize gas costs for users while maintaining high security. They are considering using a layer-2 solution. Which trade-off should they prioritize in their decision?

   • AHigher gas costs and lower security, which is acceptable for a startup.
   • BLower gas costs but potentially higher centralization and reliance on the layer-2 operator.
   • CLower gas costs and higher security with no trade-offs.
   • DHigher gas costs but complete decentralization and no reliance on any third party.
   Reveal Solution Discussion Select an answer first