Common Threats and Blockchain Security Best Practices BBLC Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   Which step in an incident response plan involves identifying that a security breach has occurred?

   • AEradication
   • BDetection
   • CRecovery
   • DContainment
   Reveal Solution Discussion Select an answer first
2. 17application · medium

   A blockchain-based identity management system allows users to sign documents with their private keys. The system is vulnerable to a replay attack, where an attacker captures a signed document and resubmits it to trick the system into accepting it again. Which cryptographic technique would best prevent this?

   • AHash the document before signing it.
   • BInclude a timestamp and a unique nonce in the signed message.
   • CEncrypt the signed document with the recipient's public key.
   • DUse a longer private key for signing.
   Reveal Solution Discussion Select an answer first
4. 18expert · hard

   A new blockchain project wants to prevent Sybil attacks and 51% attacks while keeping the network decentralized. They are considering three consensus mechanisms: Proof of Work (PoW), Proof of Stake (PoS), and Delegated Proof of Stake (DPoS). Which mechanism offers the best balance of security and decentralization for this project?

   • AProof of Stake (PoS) with a large number of validators and a high staking requirement.
   • BDelegated Proof of Stake (DPoS) with only 3 block producers.
   • CProof of Work (PoW) with a high mining difficulty but a small network.
   • DProof of Work (PoW) with a low mining difficulty.
   Reveal Solution Discussion Select an answer first
5. 19foundation · easy

   What is the main objective of a regular security audit of a blockchain system?

   • ATo create a backup of the blockchain data.
   • BTo identify and remediate vulnerabilities before they can be exploited.
   • CTo promote the blockchain to new users.
   • DTo increase the transaction speed of the blockchain.
   Reveal Solution Discussion Select an answer first
6. 20application · medium

   A blockchain network uses a proof-of-work consensus. An attacker has accumulated more than 50% of the network's hash rate. Which of the following is the MOST likely immediate consequence?

   • AThe attacker can decrypt encrypted transactions on the blockchain.
   • BThe attacker can steal private keys of other users.
   • CThe attacker can change the consensus algorithm.
   • DThe attacker can reverse transactions they have made, allowing double-spending.
   Reveal Solution Discussion Select an answer first