Encryption Algorithms (Symmetric/Asymmetric) CEH Practice Questions (Page 7)

Questions 31–35

1. 31application · medium

   A company is deploying a new IoT device with limited CPU and memory. The device must perform secure key exchange with a central server. Which algorithm is most suitable for this constrained environment?

   • ABlowfish
   • BECC (Elliptic Curve Cryptography)
   • CRSA with a 4096-bit key
   • D3DES
   Reveal Solution Discussion Select an answer first
2. 32application · medium

   A security engineer must design a secure file-transfer solution for a small team. The team members do not have a pre-shared secret, and the engineer wants to avoid manually exchanging keys. The solution must encrypt the file contents efficiently and also ensure that only the intended recipient can decrypt them. Which approach best meets these requirements?

   • AEncrypt the file with the recipient's RSA public key and send it without a session key.
   • BEncrypt the file with a static AES-256 key that all team members share and distribute it over email.
   • CGenerate a random AES-256 session key, encrypt the file with it, and encrypt the session key with the recipient's RSA public key.
   • DEncrypt the file with the sender's RSA private key and send it directly to the recipient.
   Reveal Solution Discussion Select an answer first
4. 33application · medium

   A system administrator needs to rotate encryption keys for a database that uses symmetric encryption. The database contains sensitive customer data. What is the most important consideration when rotating the keys?

   • ARe-encrypt all data with the new key and securely distribute the new key to authorized systems.
   • BUse the same key for all databases to simplify management.
   • CKeep the old key in use for all data to avoid downtime.
   • DEnsure the new key is longer than the old key.
   Reveal Solution Discussion Select an answer first
5. 34expert · hard

   A security engineer is implementing end-to-end encryption for a chat application. The application must support multiple devices per user and allow a user to read messages on any device. The engineer wants to avoid storing a single shared symmetric key on a central server. Which approach is most appropriate?

   • AUse a single symmetric key stored on the server and distribute it to all devices.
   • BGenerate a symmetric session key for each message, encrypt the message with it, and encrypt the session key with each recipient device's public key.
   • CUse Diffie-Hellman to establish a shared key between the sender and each device.
   • DUse RSA to encrypt the entire message for each device.
   Reveal Solution Discussion Select an answer first
6. 35application · medium

   A certificate authority is issuing digital certificates for a high-security government application. They need an asymmetric algorithm that provides the strongest security with the smallest key size to reduce storage and transmission overhead. Which algorithm should they choose?

   • ABlowfish
   • BECC with a 384-bit key
   • CRSA-2048
   • DDiffie-Hellman with a 2048-bit key
   Reveal Solution Discussion Select an answer first