Common Threats and Blockchain Security Best Practices BBLC Practice Questions (Page 5)

Questions 21–25

1. 21application · medium

   A consortium blockchain for cross-border trade finance uses a delegated proof-of-stake (DPoS) consensus with only 21 elected validators. A security analyst warns that an attacker who acquires a significant stake could influence validator elections and eventually control the network. Which combination of measures would most directly reduce this risk?

   • AImplement a formal verification process for the consensus protocol code.
   • BIncrease the number of validators to 101 and introduce a rotating validator schedule with random selection.
   • CDeploy a firewall that only allows validator traffic from whitelisted IP addresses.
   • DRequire all validators to run hardware security modules (HSMs) for their signing keys.
   Reveal Solution Discussion Select an answer first
2. 22application · medium

   A blockchain-based supply chain company stores the private keys for its signing accounts on a single laptop that is connected to the internet. The company wants to improve key security without sacrificing the ability to sign transactions quickly. Which approach is the most secure and practical?

   • AMove the keys to a hardware security module (HSM) that requires physical access for signing operations.
   • BPrint the keys on paper and store them in a safe, using a new key for each transaction.
   • CShare the keys among multiple employees so that no single person has the full key.
   • DStore the keys in an encrypted file on the laptop and use a strong password.
   Reveal Solution Discussion Select an answer first
4. 23expert · hard

   A company runs a blockchain node that is critical for its operations. They are experiencing a DDoS attack that is overwhelming the node's network connection. They also need to ensure that legitimate peers can still connect. Which strategy is the most effective?

   • AIncrease the node's bandwidth by upgrading the internet connection.
   • BDisable the node's network interface to stop the attack.
   • CChange the node's IP address and hope the attacker does not find it.
   • DUse a DDoS protection service that can absorb the attack and filter traffic based on peer reputation.
   Reveal Solution Discussion Select an answer first
5. 24expert · hard

   A blockchain-based supply chain platform has experienced a security incident where an attacker exploited a vulnerability in a smart contract to mint counterfeit tokens. The team has identified the vulnerability and is planning the incident response. They need to decide the order of actions. Which sequence is the MOST appropriate?

   • AConduct a forensic analysis first, then pause the contract, then deploy a patched version.
   • BNotify all users and ask them to stop using the platform, then deploy a patched version, then pause the contract.
   • CDeploy a patched version immediately, then pause the contract, then conduct a forensic analysis.
   • DContain the vulnerability by pausing the contract, then conduct a forensic analysis, then deploy a patched version.
   Reveal Solution Discussion Select an answer first
6. 25application · medium

   A user wants to create a backup of their cryptocurrency wallet's private key. Which method is the most secure and practical?

   • AStore the private key in a text file on a cloud drive.
   • BTake a photo of the private key and store it in your phone's photo gallery.
   • CWrite the mnemonic seed phrase on paper and store it in a fireproof safe.
   • DEmail the private key to yourself for safekeeping.
   Reveal Solution Discussion Select an answer first