Mitigating Blockchain Attacks and Security Practices BFC Practice Questions (Page 8)

Questions 36–40

1. 36application · medium

   A public blockchain network has seen a rise in spam transactions that fill blocks and delay legitimate transactions. The governance team wants to mitigate this without centralizing control. Which measure is most aligned with decentralized network security?

   • AHave a central operator manually approve each transaction before it is included in a block.
   • BIncrease the block size limit to accommodate all transactions.
   • CAllow miners to prioritize transactions from whitelisted addresses only.
   • DIntroduce a minimum transaction fee and dynamic fee adjustment based on network congestion.
   Reveal Solution Discussion Select an answer first
2. 37expert · hard

   A blockchain-based voting platform has just discovered that an attacker exploited a smart contract vulnerability to cast thousands of fraudulent votes. The platform must maintain the integrity of the election results while also complying with data protection regulations that require timely breach notification. What is the most appropriate incident response approach?

   • APause the voting contract, preserve all evidence, analyze the exploit, and then notify affected parties and regulators as required.
   • BImmediately notify all affected users and regulators before taking any technical action.
   • CAttempt to fork the blockchain to remove the fraudulent votes without notifying anyone.
   • DIgnore the incident because the blockchain is immutable and the votes cannot be changed.
   Reveal Solution Discussion Select an answer first
4. 38application · medium

   A blockchain-based payment company has just experienced a smart contract exploit that drained user funds. The incident response team needs to act quickly. Which first step is most appropriate for a blockchain-specific incident response plan?

   • ADelete the smart contract code from the blockchain to prevent further attacks.
   • BContact all users and ask them to stop using the platform immediately, but take no technical action.
   • CImmediately attempt to reverse the blockchain to a pre-exploit state.
   • DPause the affected smart contract if it has a kill switch, and then analyze the exploit to determine the root cause.
   Reveal Solution Discussion Select an answer first
5. 39application · medium

   A small consortium runs a permissioned blockchain with only 7 validating nodes, each operated by a different member. A governance review notes that a malicious actor could potentially overwhelm the network with fake identities to gain disproportionate influence. Which combination of measures would most directly address this risk?

   • AImplement strong identity verification for node operators and require multi-factor authentication for all administrative actions.
   • BSwitch to a proof-of-work consensus algorithm to make node creation computationally expensive.
   • CIncrease the block size and reduce the block interval to speed up transaction processing.
   • DDeploy a hardware security module (HSM) at each node to store private keys.
   Reveal Solution Discussion Select an answer first
6. 40foundation · easy

   Which cryptographic security practice is most important for protecting a user's private key in a blockchain system?

   • APrinting the private key on paper and storing it in a desk drawer
   • BUsing a simple password to encrypt the private key
   • CSharing the private key with a trusted third party
   • DStoring the private key in a hardware security module (HSM)
   Reveal Solution Discussion Select an answer first