Cryptography Concepts EHE Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   Which key is used to create a digital signature?

   • AThe sender's private key
   • BThe sender's public key
   • CA symmetric session key
   • DThe recipient's public key
   Reveal Solution Discussion Select an answer first
2. 17application · medium

   A security analyst is investigating a suspected attack where an attacker positioned between two communicating parties intercepts the public key exchange and substitutes their own key. The attacker then relays messages between the parties, who believe they are communicating directly. Which attack is this?

   • ABrute-force attack
   • BMan-in-the-middle attack
   • CSide-channel attack
   • DReplay attack
   Reveal Solution Discussion Select an answer first
4. 18expert · hard

   A company is implementing a secure messaging system. They need to ensure that messages are confidential and that the sender cannot deny sending them. The system currently uses only symmetric encryption with a shared key. What is the most important addition to achieve non-repudiation?

   • AAdd a timestamp to each message.
   • BAdd digital signatures using the sender's private key.
   • CUse a hash of the message for integrity.
   • DUse a longer symmetric key.
   Reveal Solution Discussion Select an answer first
5. 19foundation · easy

   Which of the following is a common symmetric encryption algorithm?

   • AAES
   • BRSA
   • CSHA-256
   • DECC
   Reveal Solution Discussion Select an answer first
6. 20expert · hard

   A security auditor is reviewing a system that stores user passwords. The system currently uses unsalted MD5 hashes. The auditor warns that this is vulnerable to rainbow table attacks. What is the most effective remediation?

   • AUse SHA-256 without a salt.
   • BMigrate to salted hashes using a strong algorithm like bcrypt or Argon2.
   • CAdd a static salt to all passwords and keep using MD5.
   • DEncrypt the MD5 hashes with AES.
   Reveal Solution Discussion Select an answer first