Advanced Cryptographic Mechanisms in Blockchain Security BBLC Practice Questions (Page 3)

Questions 11–15

1. 11foundation · easy

   In a blockchain transaction, which key is used to create a digital signature, and which key is used by others to verify it?

   • ASender's public key to sign; sender's private key to verify
   • BSender's private key to sign; sender's public key to verify
   • CA shared symmetric key to sign and verify
   • DRecipient's public key to sign; recipient's private key to verify
   Reveal Solution Discussion Select an answer first
2. 12foundation · easy

   In a blockchain context, what is a common use of zero-knowledge proofs?

   • ATo replace the need for digital signatures
   • BTo prove that a transaction is valid without revealing the transaction details
   • CTo encrypt the entire blockchain so that only miners can read it
   • DTo speed up block generation by reducing the hash computations
   Reveal Solution Discussion Select an answer first
4. 13application · medium

   A blockchain architect is planning a new enterprise blockchain that must remain secure for the next 20 years. They are concerned about future quantum computers breaking ECDSA signatures. Which approach should they take to mitigate this risk?

   • AAdopt post-quantum cryptographic algorithms that are resistant to quantum attacks.
   • BUse SHA-512 for all hashing operations.
   • CRely on the assumption that quantum computers will not be built.
   • DIncrease the ECC key size to 512 bits.
   Reveal Solution Discussion Select an answer first
5. 14application · medium

   A financial consortium wants to prove that a client meets a regulatory threshold (e.g., balance above $10,000) without revealing the actual balance or any other transaction details. Which cryptographic technique should they implement?

   • AHomomorphic encryption of the balance, allowing the network to compute whether it exceeds the threshold.
   • BA digital signature from the client that includes the balance as part of the signed message.
   • CA zero-knowledge proof that demonstrates the balance is above the threshold without disclosing the exact value.
   • DA hash of the balance that is compared to a public hash of the threshold.
   Reveal Solution Discussion Select an answer first
6. 15application · medium

   A blockchain platform is selecting a cryptographic algorithm for generating key pairs and signing transactions. They need strong security with smaller key sizes and lower computational overhead compared to RSA. Which algorithm should they choose?

   • AAES-256 for digital signatures.
   • BRSA with 2048-bit keys.
   • CElliptic Curve Cryptography (ECC) such as secp256k1.
   • DSHA-256 as a key generation algorithm.
   Reveal Solution Discussion Select an answer first