Cryptographic Principles BDC Practice Questions (Page 5)

Questions 21–25

1. 21application · medium

   A developer notices that a smart contract's execution time varies significantly depending on the private key used to sign the transaction. An attacker could potentially exploit this to recover the private key. Which type of attack is this?

   • ASide-channel attack
   • BMan-in-the-middle attack
   • CBrute-force attack
   • DReplay attack
   Reveal Solution Discussion Select an answer first
2. 22expert · hard

   A security team is evaluating a potential vulnerability in a smart contract that uses a digital signature for authorization. They discover that the contract does not check the timestamp of the signature. Which attack is most likely to succeed?

   • ASide-channel attack
   • BBrute-force attack
   • CMan-in-the-middle attack
   • DReplay attack
   Reveal Solution Discussion Select an answer first
4. 23foundation · easy

   In the process of creating a digital signature, what is typically hashed before encryption with the private key?

   • AThe public key
   • BThe private key
   • CThe timestamp
   • DThe message content
   Reveal Solution Discussion Select an answer first
5. 24application · medium

   A developer is implementing a document signing feature. The requirement is that any recipient can verify the document's origin and integrity without needing a shared secret. Which process should the developer implement?

   • AHash the document, encrypt the hash with the sender's private key, and attach it to the document.
   • BHash the document and encrypt the entire document with the sender's public key.
   • CEncrypt the document with a symmetric key and share the key via a secure channel.
   • DCompute a MAC using a shared secret and append it to the document.
   Reveal Solution Discussion Select an answer first
6. 25application · medium

   A security auditor is reviewing a system that stores user passwords as SHA-256 hashes without salt. Which vulnerability is most directly associated with this practice?

   • AMan-in-the-middle attacks, because SHA-256 is not a keyed hash.
   • BSide-channel attacks, because SHA-256 is fast.
   • CNon-repudiation issues, because SHA-256 is not a signature.
   • DRainbow table attacks, because identical passwords produce identical hashes.
   Reveal Solution Discussion Select an answer first