Which process converts plaintext into ciphertext to protect confidentiality?

• A. Encoding
• B. Signing
• C. Encryption
• D. Hashing

Answer: (C)

Encrypting data protects confidentiality by converting plaintext into ciphertext using a cryptographic algorithm and a key. This transformation makes the information unreadable to anyone who doesn’t possess the appropriate key, so the content remains confidential even if intercepted. Decryption with the key reverses the process to recover the original plaintext.

Other options don’t provide confidentiality in the same way. Encoding changes data into a different representation for compatibility or transmission (like base64) and is easily reversible, not aimed at security. Signing creates a digital signature to verify origin and integrity, not to hide content. Hashing produces a fixed-length digest to detect tampering and is not reversible, so it isn’t used to conceal data.