Fundamental Concepts and Working Principles of Blockchain Technology BBLC Practice Questions (Page 8)

Questions 36–40

1. 36foundation · easy

   Why is a hash function considered 'one-way'?

   • AIt is computationally infeasible to derive the original input from the hash.
   • BIt can be reversed only with a secret key.
   • CIt can only be used once in a blockchain.
   • DIt produces the same output for different inputs.
   Reveal Solution Discussion Select an answer first
2. 37expert · hard

   A new cryptocurrency project wants to achieve decentralization but also needs to be energy-efficient and allow token holders to influence governance. They are considering Proof of Stake (PoS). What is a key trade-off they must address?

   • APoS is slower than PoW, making it unsuitable for most applications.
   • BPoS allows anyone to participate without any stake, making it more inclusive.
   • CPoS reduces energy consumption compared to PoW, but it can lead to concentration of power among large token holders.
   • DPoS is more secure than PoW because it requires physical hardware.
   Reveal Solution Discussion Select an answer first
4. 38expert · hard

   A startup is building a decentralized application (dApp) for peer-to-peer energy trading. They want to avoid a single point of failure and ensure that no central authority can censor transactions. However, they also need to comply with local regulations that require them to be able to freeze the account of a user who is found to be trading illegally. Which blockchain architecture best reconciles these conflicting requirements?

   • AA hybrid blockchain where transactions are public but a central authority can override any transaction.
   • BA private blockchain controlled by the startup, allowing them to freeze accounts at will.
   • CA permissioned blockchain with a governance framework that allows a consortium of regulators and stakeholders to vote on freezing accounts, while the network remains decentralized among multiple nodes.
   • DA public blockchain with no built-in governance, because decentralization is the top priority.
   Reveal Solution Discussion Select an answer first
5. 39foundation · easy

   What makes blockchain transactions auditable?

   • ATransactions are recorded in a log file that can be edited by administrators.
   • BTransactions are stored in a separate database that can be deleted after audits.
   • CEach transaction is permanently recorded with a timestamp and linked to previous transactions.
   • DOnly auditors have access to the transaction history.
   Reveal Solution Discussion Select an answer first
6. 40expert · hard

   A government agency is considering a blockchain for land registry records. They need to ensure data integrity and public trust, but they also have legal requirements to correct erroneous records. Which approach best balances immutability with the need for corrections?

   • AUse a blockchain that allows authorized administrators to delete incorrect records.
   • BUse a public blockchain and rely on the community to vote on corrections.
   • CUse a centralized database instead, because blockchain cannot handle corrections.
   • DUse an append-only blockchain where corrections are recorded as new transactions that supersede the old ones.
   Reveal Solution Discussion Select an answer first