Network Communication and Protocol Layers BDC Practice Questions (Page 2)

Questions 6–10

1. 6application · medium

   A blockchain network is concerned about Sybil attacks where an attacker creates many fake identities to gain disproportionate influence. Which mechanism is most effective in a permissioned blockchain?

   • AAllow any node to join without verification to promote decentralization.
   • BRequire nodes to authenticate with a certificate authority (CA) before joining the network.
   • CUse a proof-of-work algorithm with a low difficulty target.
   • DIncrease the block size to allow more transactions per block.
   Reveal Solution Discussion Select an answer first
2. 7application · medium

   A blockchain developer is designing a custom blockchain protocol. They want to separate the concerns of data transmission, block validation, and application-level smart contract execution. Which architectural approach best achieves this separation?

   • AUse a monolithic codebase where all functions are tightly coupled for performance.
   • BOutsource all networking to a third-party cloud service.
   • CRely on a single protocol layer that handles both networking and execution.
   • DImplement a layered protocol stack with separate modules for networking, consensus, and execution.
   Reveal Solution Discussion Select an answer first
4. 8application · medium

   A blockchain network uses a block propagation mechanism where a node that receives a new block validates it and then forwards it to its peers. What is the primary purpose of this validation before forwarding?

   • ATo increase the block size limit.
   • BTo allow the node to charge a fee for forwarding.
   • CTo prevent the propagation of invalid blocks and reduce network waste.
   • DTo ensure the node's local time is synchronized.
   Reveal Solution Discussion Select an answer first
5. 9application · medium

   A blockchain developer is concerned about an attacker isolating a node from honest peers to feed it false transactions. Which mitigation is most effective against this specific attack?

   • ADisable inbound connections entirely
   • BIncrease the number of outbound connections and randomly select peers from a diverse set
   • CUse a single, well-known DNS seed to discover peers
   • DRestrict the node to connect only to a fixed list of trusted peers
   Reveal Solution Discussion Select an answer first
6. 10application · medium

   A developer is optimizing a blockchain network to reduce block propagation latency. Which strategy is most effective?

   • AWait for each node to request the block before sending
   • BUse a centralized server to distribute blocks
   • CUse compact block relay that sends only transaction IDs and reconstructs the block from the mempool
   • DSend the full block to every node simultaneously
   Reveal Solution Discussion Select an answer first