Certified Ethical Hacker Cryptography Fundamentals 2 — Questions and Answers
Question 1: Which encryption type uses the same key for both encryption and decryption?
- Symmetric encryption (Correct answer)
- Asymmetric encryption
- Hashing
- Steganography
Correct answer: Symmetric encryption
Symmetric encryption uses a single shared secret key for both operations.
Question 2: What is the key size used by the AES algorithm in its strongest standard configuration?
- 56 bits
- 128 bits
- 256 bits (Correct answer)
- 512 bits
Correct answer: 256 bits
AES supports 128, 192, and 256-bit keys, with 256-bit being the strongest.
Question 3: Which of the following is a stream cipher?
- AES
- RC4 (Correct answer)
- Blowfish
- 3DES
Correct answer: RC4
RC4 is a stream cipher that encrypts data one bit or byte at a time.
Question 4: In asymmetric cryptography, which key is used to encrypt a message sent to a recipient?
- The sender's private key
- The recipient's public key (Correct answer)
- The recipient's private key
- A shared symmetric key
Correct answer: The recipient's public key
Messages are encrypted with the recipient's public key so only their private key can decrypt them.
Question 5: What property of a hash function ensures it is computationally infeasible to find two inputs producing the same output?
- Reversibility
- Collision resistance (Correct answer)
- Confidentiality
- Key exchange
Correct answer: Collision resistance
Collision resistance means two different inputs should not produce the same hash value.
Question 6: Which algorithm is primarily used for secure key exchange over an insecure channel?
- Diffie-Hellman (Correct answer)
- MD5
- AES
- SHA-256
Correct answer: Diffie-Hellman
Diffie-Hellman allows two parties to establish a shared secret over an untrusted network.
Question 7: What does a digital signature primarily provide?
- Confidentiality only
- Authentication and integrity (Correct answer)
- Faster encryption
- Key generation
Correct answer: Authentication and integrity
A digital signature verifies the sender's identity and confirms the message was not altered.
Certified Ethical Hacker Cryptography Fundamentals 2
Which encryption type uses the same key for both encryption and decryption?