Securing Blockchain Transactions with Cryptographic Techniques BFC Practice Questions (Page 6)

Questions 26–30

1. 26foundation · easy

   What is the first step in signing a blockchain transaction with a private key?

   • AVerify the recipient's digital signature
   • BEncrypt the transaction data with the recipient's public key
   • CCreate a hash of the transaction data
   • DBroadcast the transaction to the network
   Reveal Solution Discussion Select an answer first
2. 27foundation · easy

   In public-key cryptography used in blockchain, what is the role of the private key?

   • AIt is derived from the public key and used for address generation
   • BIt is shared publicly to allow others to verify transactions
   • CIt is used to encrypt data that only the public key can decrypt
   • DIt is kept secret and used to create digital signatures
   Reveal Solution Discussion Select an answer first
4. 28foundation · easy

   After a transaction is signed with a private key, what is typically done with the signature?

   • AIt is attached to the transaction and broadcast to the network
   • BIt is kept secret and never shared
   • CIt is used to encrypt the transaction data
   • DIt is stored only on the sender's device
   Reveal Solution Discussion Select an answer first
5. 29foundation · easy

   What does a digital signature on a blockchain transaction primarily authenticate?

   • AThe identity of the recipient of the transaction
   • BThat the transaction was authorized by the owner of the private key
   • CThat the transaction has been confirmed by the network
   • DThe amount of cryptocurrency being transferred
   Reveal Solution Discussion Select an answer first
6. 30application · hard

   A logistics company uses a blockchain to share shipment data with partners. They need to ensure that only authorized partners can read the shipment details, but they also need to prove that a specific partner submitted a particular update. Which approach should they use?

   • AHash the shipment data and store the hash on the blockchain; store the plaintext off-chain.
   • BEncrypt the shipment data with the submitting partner's public key and sign the ciphertext with the same partner's private key.
   • CEncrypt the shipment data with a symmetric key and share that key with all partners; sign the encrypted data with the submitting partner's private key.
   • DUse a hybrid scheme: encrypt the data with a symmetric key, encrypt that key with each authorized partner's public key, and sign the encrypted data with the submitter's private key.
   Reveal Solution Discussion Select an answer first