Steganography: What Is It and How Does Steganography Work?
Steganography is the practice of hiding an image, message, or file within something that isn't a secret.
Kids even dabble in steganography. If you ever played with magic ink to bring secret notes to life, you've used it. And if you ever wrote your love a coded message inside something like a homework assignment, you've used a stenographic trick too.
But plenty of adults use steganography too. And sometimes, hackers use the technique to shield their attacks from your detection.
How Does Steganography Work?
There are literally dozens of ways to hide messages, and each one works differently. But most steganography experts rely on the same principles to do their work.
Steganography relies on several pieces, including:
- Payloads. What do you want to embed or hide?
- Carriers. What file or asset will hide your payload?
- Channels. What type of carrier will you use?
- Package. How will the carrier look or respond when buried with the payload?
- Key. How will the recipient decode your message and find the payload?
Without all of these elements, you can't execute any kind of steganography. But with them, you're ready to get started.
Steganography Past and Present
Modern technology takes steganography to new heights. But the practice is ancient.
The word steganographia was coined in 1499 in a book deemed so dangerous that it wasn't published until 1606. It offered plenty of ancient methods used to hide messages.
Even without a published manual, people figured out how to hide messages. Ancient methods involved:
- Wax. Notes were buried under multiple layers of material that could be melted away.
- Wordplay. The second or third letter in each word could be strung together to form secret messages.
- Pictography. Tiny animals or leaves represented family crests, and they could outline upcoming alliances.
- Ink. Notes were painted on soldiers’ bodies and could be revealed with juice or fluids.
Modern steganographers add or replace bits in files with secret data. For example, they might alter the file header of a document, attaching a few bits that only the recipient would look for.
Where Is Steganography Used?
Imagine that you have a secret note you must get to a colleague or enemy. What kind of channel can you use?
Steganography is used in almost every type of file you can imagine, including: