Topic: Cryptography and Network Security
Which of the following does not use key(s)?
- A. Symmetric Ciphers
- B. Generation of Message Digest
- C. Generation of Message Authentication Code
- D. Key exchange algorithms
Answer: B. Generation of Message Digest
Explanation: A Message Digest (like SHA-256 or MD5) is a one-way cryptographic hash function that takes an arbitrary amount of data and generates a fixed-size hash. It solely depends on the input data and operates without any secret keys. In contrast, symmetric ciphers, MACs, and key exchange algorithms explicitly require keys.