What best describes the difference between hashing and encryption?

• A. Hashing is reversible; encryption is not.
• B. Hashing uses keys; encryption does not.
• C. Hashing is a one-way fixed-size digest; encryption is reversible with a key.
• D. Hashing provides confidentiality; encryption provides integrity.

Answer: (C)

Hashing and encryption serve different security goals. Hashing takes input data and produces a fixed-length digest that cannot be practically reversed to reveal the original data. This one-way nature makes hashing ideal for integrity checks and safe password storage. Encryption, on the other hand, converts plaintext into ciphertext in a way that can be reversed using a key, allowing the original data to be recovered by someone with the correct key. So the best description is that hashing yields a one-way, fixed-size digest, while encryption is reversible with a key. The other statements mischaracterize one or both aspects: hashing is not reversible, hashing does not use keys, and hashing is about integrity (not confidentiality) whereas encryption protects confidentiality.