Which of the following is cited as an example of technical steganography?

• A. Public-key Cryptography
• B. Invisible Ink
• C. Hashing
• D. Color depth reduction

Answer: (B)

Steganography is about hiding a message inside something that looks ordinary so others don’t even realize a secret is there. Invisible ink fits this idea perfectly: the writing on the page appears normal, but the hidden message only becomes visible when you apply a specific reveal method (like heat, a chemical, or UV light). It showcases concealing the existence of information rather than just scrambling its content.

By comparison, public-key cryptography focuses on disguising the content itself, not its presence, which is why it isn’t an example of steganography. Hashing protects integrity and doesn’t carry hidden payloads. Color depth reduction is a digital technique that can be used to alter data but isn’t the classic, widely cited example of hiding a message in a carrier the way invisible ink is.