Advanced Cryptographic Mechanisms in Blockchain Security BBLC Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   Why do quantum computers pose a threat to current blockchain cryptographic mechanisms?

   • AThey can break the mathematical problems underlying public-key cryptography, such as ECC and RSA
   • BThey can intercept and decrypt all network traffic
   • CThey can reverse SHA-256 hashes to recover original data
   • DThey can mine blocks faster than classical computers
   Reveal Solution Discussion Select an answer first
2. 2application · medium

   A blockchain startup is designing a private permissioned ledger for supply-chain traceability. They need to prove to auditors that a historical block has not been altered, but they do not want to reveal the entire block's transaction data. Which combination of cryptographic mechanisms best meets this requirement?

   • AEncrypt each transaction with the auditor's public key and store the ciphertext in the block.
   • BStore the block header hash in an external audit log and use Merkle proofs to verify individual transactions.
   • CReplace the block hash with a digital signature from the previous block's miner.
   • DStore the entire block in a public cloud bucket and share read-only access with auditors.
   Reveal Solution Discussion Select an answer first
4. 3application · medium

   A voting blockchain stores encrypted ballots. The election authority needs to tally the votes without decrypting individual ballots. Which cryptographic technique should they use?

   • AHash each ballot and count the hashes.
   • BDigital signatures to authenticate each ballot, then decrypt all ballots.
   • CHomomorphic encryption to add encrypted votes and decrypt only the final tally.
   • DZero-knowledge proofs to prove each vote is valid without tallying.
   Reveal Solution Discussion Select an answer first
5. 4foundation · easy

   What is the core idea of a zero-knowledge proof?

   • ATo create a digital signature that hides the signer's identity
   • BTo encrypt data so that only the intended recipient can read it
   • CTo prove knowledge of a secret without revealing the secret itself
   • DTo compress transaction data to save space
   Reveal Solution Discussion Select an answer first
6. 5foundation · easy

   What is the primary purpose of using SHA-256 in a blockchain's Merkle tree?

   • ATo generate the private keys for users
   • BTo compress the block to reduce storage
   • CTo create fixed-size digests of transaction data for efficient verification
   • DTo encrypt the transaction data
   Reveal Solution Discussion Select an answer first