Privacy and Zero-Knowledge Innovations BDC Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard

   A blockchain platform must support private smart contract execution for a high-throughput enterprise application. The team is choosing between zk-SNARKs and zk-STARKs. The application requires low on-chain verification gas costs, but the team is concerned about the long-term security of a trusted setup. They have a short deployment deadline. Which choice best balances these constraints?

   • AUse a hybrid approach: zk-SNARKs for some transactions and zk-STARKs for others
   • BUse Bulletproofs, which have no trusted setup and moderate verification costs
   • CUse zk-SNARKs with a one-time trusted setup ceremony, accepting the setup risk to achieve low verification costs
   • DUse zk-STARKs with a transparent setup, accepting higher verification gas costs
   Reveal Solution Discussion Select an answer first
2. 27foundation · easy

   Which of the following is a key difference between zk-SNARKs and zk-STARKs?

   • Azk-SNARKs require a trusted setup, while zk-STARKs do not.
   • Bzk-SNARKs are quantum-resistant, while zk-STARKs are not.
   • Czk-SNARKs produce larger proofs than zk-STARKs.
   • Dzk-SNARKs are slower to verify than zk-STARKs.
   Reveal Solution Discussion Select an answer first
4. 28application · medium

   A blockchain gaming company wants to allow players to prove they have completed a level without revealing their exact score. The game runs on a mobile device with limited battery and CPU. The team is choosing between zk-SNARKs and zk-STARKs. Which factor is most likely to influence their decision?

   • AThe need for a trusted setup
   • BProving time and computational overhead on the client device
   • CThe availability of open-source libraries
   • DThe size of the on-chain proof storage
   Reveal Solution Discussion Select an answer first
5. 29expert · hard

   A developer is building a private voting smart contract. The contract must count votes without revealing individual votes, and the final tally must be publicly verifiable. The developer is considering using homomorphic encryption or zero-knowledge proofs. Which approach is more appropriate for this use case?

   • AUse a trusted third party to count votes and publish the result
   • BUse only zero-knowledge proofs to prove each vote is valid, and publish the votes in plaintext
   • CUse only homomorphic encryption and publish the encrypted tally
   • DUse homomorphic encryption to aggregate votes, then generate a zero-knowledge proof that the tally is correct
   Reveal Solution Discussion Select an answer first
6. 30expert · hard

   A company is developing a private smart contract that computes a credit score based on multiple financial inputs. The inputs are sensitive, and the output must be verifiable by a third party. The team is considering using zk-SNARKs. Which limitation of zk-SNARKs is most likely to impact the design?

   • AThe circuit must be fixed at setup time, making it difficult to update the credit scoring logic.
   • BThe prover must be a trusted party.
   • CThe proof size is too large for on-chain storage.
   • DThe verification time is too slow for real-time applications.
   Reveal Solution Discussion Select an answer first