In the encryption explanation, which statement correctly describes the relationship between plaintext and ciphertext?

• A. The ciphertext is decrypted back to plaintext using the key.
• B. The plaintext is never stored.
• C. The encryption process converts plaintext to ciphertext using a key.
• D. Encryption makes data larger but not secure.

Answer: (C)

Encryption is the process of turning readable data (plaintext) into an unreadable form (ciphertext) using a key. The essential idea is that the plaintext is transformed into ciphertext with the key, and this ciphertext can later be turned back into plaintext by applying the decryption process with the same or a related key. This makes the statement describing the transformation from plaintext to ciphertext the best fit, because it directly captures what encryption does. The other ideas describe the reverse process, or make claims about storage or data size that aren’t defining features of how encryption relates plaintext and ciphertext.