Consensus and Scalability Innovations BDC Practice Questions (Page 2)

Questions 6–10

1. 6expert · hard

   A consortium of 15 banks is designing a permissioned blockchain for cross-border payments. They need high throughput and low latency, but they also want to avoid a single point of failure and ensure that no small group can control the network. They are considering DPoS and PBFT. Which choice best meets their requirements?

   • AA DAG-based consensus, because it allows all banks to process transactions in parallel without any coordination.
   • BPBFT, because it allows all 15 banks to participate in consensus and provides immediate finality without elected delegates.
   • CDPoS, because it elects a few delegates to improve throughput, and the banks can vote to replace them.
   • DPoW, because it is the most decentralized and does not require a known validator set.
   Reveal Solution Discussion Select an answer first
2. 7expert · hard

   A decentralized exchange wants to offer near-instant trades with low fees. They are considering a Layer 2 solution. They need to ensure that users can withdraw funds to the main chain at any time, even if the Layer 2 operator is malicious. Which solution provides this guarantee?

   • AA state channel, because it allows users to close the channel unilaterally with the latest signed state.
   • BA sidechain, because it has its own consensus and does not rely on the main chain for security.
   • CAn optimistic rollup, because it allows users to submit fraud proofs to challenge invalid state transitions and withdraw funds.
   • DA plasma chain, because it uses fraud proofs and allows users to exit within a challenge period.
   Reveal Solution Discussion Select an answer first
4. 8foundation · easy

   What is a primary scalability benefit of DAG-based consensus?

   • AIt reduces the number of nodes needed to secure the network
   • BIt allows transaction throughput to increase as more users join
   • CIt requires less storage per node
   • DIt eliminates the need for transaction fees
   Reveal Solution Discussion Select an answer first
5. 9application · medium

   A DeFi protocol wants to allow users to move assets between a public chain and a sidechain. They need to ensure that the bridge is secure and does not introduce a single point of failure. Which approach should they take?

   • AUse a bridge with a decentralized set of validators that sign off on lock and mint events, with a threshold signature scheme.
   • BUse a sidechain that is pegged to the main chain but controlled by the protocol team.
   • CUse a single trusted custodian to hold the assets on the main chain.
   • DUse a simple hash-locking atomic swap for every asset transfer.
   Reveal Solution Discussion Select an answer first
6. 10application · medium

   A startup is building a lightweight IoT payment system where devices need to validate micro-transactions quickly without waiting for block confirmations. They are considering a DAG-based structure instead of a traditional blockchain. Which benefit of DAG-based consensus most directly addresses their need?

   • AA single global ordering of all transactions, simplifying the consensus process.
   • BParallel transaction processing, allowing multiple transactions to be confirmed concurrently.
   • CLower energy consumption because no mining is required.
   • DBuilt-in cross-chain interoperability protocols.
   Reveal Solution Discussion Select an answer first