Steganography

Hide the existence of a message rather than its content. No key, so no security service, but it denies the adversary traffic knowledge.

Hidingdemo

Objectives

Hide and recover a secret inside an innocent-looking cover text.
Contrast hiding existence with hiding content.
Explain why steganography complements encryption and never replaces it.

50%

Cryptography hides the content. Steganography hides the existence.

Cover text (looks innocent)

Secret

carrier: select it, copy it, paste it anywhere

what came back out

The secret is carried in zero-width characters between the visible ones. Character count: n/a

No key, so no security service. Once the trick is known, everyone reads it. What it denies the adversary is traffic knowledge, so encrypt first and hide the ciphertext.

step 1/2

CPE 645 / CS 685

Steganography

Product Ciphers

Where Each One Breaks