You must be asking "what the heck is Steganography?" Well it's not a dinosaur on Jurassic Park. It's the art and science of hiding messages so that nobody even knows the messages are there. It's kind of like the disappearing ink we all played with when we were kids. You write a message and it disappears, anyone seeing the paper doesn't notice a message since it disappeared, and the intended recipient uses the appropriate reagent to make the message appear again.

Today's Steganography hides information in computer files. The payload is the information that's hidden, while the carrier is the data file into which the payload is hidden.

Hiding a message is even better than cryptography because the very existence of the message is hidden. Nobody will use a supercomputer to crack the message since it's not apparent that there is a message. Of course, you can encrypt the message before you hide it to add an additional level of security.

Uses for Steganography

There are two categories for using Steganography: legitimate and non-legitimate. I'll mention both right now.

Legitimate Uses for Steganography

One of the most common legitimate uses of Steganography is to watermark images. The watermarks aren't the ones you see in many copyrighted photographs. They're hidden, and therefore not visible. That means that they can be used without those bothersome visible logos, or watermarks. Images are watermarked so that their source can be identified. So if someone makes generous use of a copyrighted image, it's an easy matter for the copyright owner to use special software to check for the implanted watermark. And these watermarks usually stay intact, even if the image is edited and resaved.

Another use for Steganography is when confidential information is hidden in a carrier file before it's transmitted. In this way, there's a reduced risk of the information being compromised if the carrier file is intercepted.

Non-Legitimate Uses for Steganography

Of course, for almost every technology there's a dark side. There have been a number of cases where confidential information was hidden within a carrier file and sent to a competitor. In spite of how hard companies try to prevent corporate espionage, the use of Steganography makes it extremely difficult.

Contraband can be hidden in a carrier image. This might include plans for bombs, illicit pictures, or terrorist documents.