Proof of Stake (PoS) and Derivative Protocols BDC Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard

   A developer is evaluating Proof of Importance (PoI) for a social media token. They want to reward active users, not just wealthy ones. Which trade-off should they consider?

   • APoI is more energy-efficient than Proof of Work
   • BPoI requires users to lock up tokens for a long period
   • CPoI is less secure than Proof of Stake because it does not use slashing
   • DPoI can be gamed by users creating fake activity to boost their importance score
   Reveal Solution Discussion Select an answer first
2. 27application · medium

   A developer is explaining to a client why a Proof of Stake blockchain can achieve consensus without the massive electricity consumption of Proof of Work. Which statement is accurate?

   • APoS replaces computational work with an economic stake, so validators are selected based on the amount they lock up
   • BPoS consumes less energy because it uses a simpler cryptographic hash function
   • CPoS achieves consensus by allowing any user to create a block without any cost
   • DPoS uses a central authority to validate transactions, eliminating the need for mining
   Reveal Solution Discussion Select an answer first
4. 28expert · hard

   A security auditor is evaluating a Proof of Stake network that has been running for three years. They are concerned about a long-range attack where an attacker tries to rewrite history from a point in the past. Which mitigation is most effective?

   • AShorten the block time to make history longer
   • BRequire validators to lock stake for a longer period
   • CUse periodic checkpointing where finalized blocks are signed by a trusted committee
   • DIncrease the block reward to attract more validators
   Reveal Solution Discussion Select an answer first
5. 29application · medium

   A startup is building a permissioned blockchain for inter-bank settlements. They want to avoid the energy costs of Proof of Work and need fast finality with known participants. They plan to use a Proof of Stake model where only approved banks can become validators. Which additional mechanism is most critical to enforce accountability and prevent misbehavior?

   • AA longer block interval to give validators more time to verify transactions
   • BA public transaction ledger to allow external auditors to monitor validator activity
   • CSlashing conditions that penalize validators for equivocation or signing conflicting blocks
   • DA higher minimum stake requirement to ensure only wealthy banks participate
   Reveal Solution Discussion Select an answer first
6. 30foundation · easy

   What is a common characteristic of staking lock-up periods in Proof of Stake systems?

   • AStaked tokens can be withdrawn at any time without any delay
   • BStaked tokens are transferred to a central authority
   • CStaked tokens are burned and permanently removed from circulation
   • DStaked tokens are typically locked for a period and cannot be transferred or sold immediately
   Reveal Solution Discussion Select an answer first