Advanced Cryptographic Mechanisms BDC Practice Questions (Page 1)

Questions 1–5

1. 1application · hard

   A developer is implementing a multi-signature wallet that requires 2-of-3 signatures to authorize a transaction. The wallet uses Schnorr signatures. What is a key advantage of using Schnorr signatures in this multi-signature scenario?

   • ASchnorr signatures are quantum-resistant
   • BSchnorr signatures are faster to generate than ECDSA
   • CSchnorr signatures allow recovery of the private key from the signature
   • DMultiple signatures can be aggregated into a single signature
   Reveal Solution Discussion Select an answer first
2. 2application · medium

   A decentralized identity platform needs to let users authenticate to a service without the service learning any personal attributes, only that the user is over 18 and a citizen of a specific country. Which cryptographic mechanism should be used?

   • AA digital signature from the user's identity provider over the user's birth date and nationality.
   • BA zero-knowledge proof of the required attributes, issued as a verifiable credential.
   • CA hash of the user's birth date and nationality, sent to the service.
   • DA symmetric encryption of the user's attributes, with the key shared with the service.
   Reveal Solution Discussion Select an answer first
4. 3foundation · easy

   In the context of blockchain security, what is the primary purpose of advanced cryptographic mechanisms?

   • ATo provide a framework for smart contract execution and business logic automation
   • BTo encrypt all transaction data so that no one can read it, including authorized parties
   • CTo replace the need for consensus algorithms in distributed networks
   • DTo ensure data integrity, authenticate participants, and enable non-repudiation of transactions
   Reveal Solution Discussion Select an answer first
5. 4expert · hard

   A consortium blockchain for intellectual property rights needs to allow creators to prove they owned a work at a certain time, while also allowing them to license the work without revealing the full content to potential licensees. The system must also prevent the creator from falsely claiming a later work was created earlier. Which combination of mechanisms is most appropriate?

   • AUse a ring signature to sign the work, hiding the creator's identity.
   • BStore a hash of the work on-chain with a timestamp, and use zero-knowledge proofs to prove ownership and licensing terms.
   • CUse a homomorphic encryption of the work, allowing licensees to compute on it without seeing it.
   • DStore the full work on-chain encrypted, and use a digital signature for licensing.
   Reveal Solution Discussion Select an answer first
6. 5application · hard

   A developer is building a decentralized identity system where users must prove they own a private key corresponding to a public identifier without revealing the key. The system also needs to allow selective disclosure of attributes (e.g., prove age > 18 without revealing birthdate). Which advanced cryptographic mechanism is most appropriate?

   • AZero-knowledge proofs
   • BHash-based commitment schemes
   • CSymmetric encryption of the private key
   • DDigital signatures with a public key certificate
   Reveal Solution Discussion Select an answer first