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Introduction to Steganography

Art by Pat Simpson

Two secret messages are hidden in this image.

How do you decode them? With steganography—the use of advanced mathematics, statistics, and computer science to embed or decode encrypted messages in images, texts, or sounds.

So, what are the embedded messages? Here’s a way to reveal them:

Basic Decoding

Every color is a combination of different levels of red, green, and blue. Each pixel in a digital color image has three values corresponding to these three levels.

To decode the first message, take the red level of every pixel from the image with the hidden message and then subtract the red level of every pixel from the original image. You’ll get the following 0 & 1 sequence:


Next, group them into 7 bits and look in the ASCII code table to find out which character each binary number represents.

Want to find out for yourself? You need both the original image and the image with hidden messages, and a software package that can disclose detail information of a jpeg file, such as Matlab.

We bet you have some questions now. Like, how do you know which color was used to hide the messages? What if ASCII code wasn’t used? What if the message is scattered through all three colors?

These are the interesting questions steganographers love to resolve.

What background do you need to become a steganographer?

Find out how to earn up to $10,000 in scholarship funds for IUP's M.S. in Applied Mathematics degree program.

M.S. in Applied Mathematics

In the M.S. in Applied Math program at IUP, you’ll get a background in applied mathematics, statistics, and operations research, and use state-of-the-art software. You’ll be prepared to work in scientific and quantitative fields or pursue a Ph.D. program in applied math, statistics, or operations research.

Get more information on the M.S. in Applied Math.

Apply for $10,000 scholarship.

Apply to the program.

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