Steganography – SY0-601 CompTIA Security+ : 2.8

It’s sometimes easier to transfer secret information through the use of a concealment. In this video, you’ll learn about obfuscation, steganography, and how to hide data inside of image, audio, and video files.

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Obfuscation is the process of taking something that would commonly be relatively easy to understand and make it very difficult to understand. This doesn’t make it impossible to understand. But it does make it a lot more difficult for humans to be able to look at or read through some information and be able to understand exactly what that information is saying.

We commonly see things like obfuscation being done with source code. This means the programming language that we’re using is able to work properly. But we, as humans, aren’t able to read through the code and understand exactly what’s happening with the logic of that program.

Another type of obfuscation is used to hide information within an image. We refer to this as steganography. Steganography has a basis in Greek that means concealed writing. And it’s a way of storing information that doesn’t necessarily make it more secure, but it certainly makes it more difficult to know that that information is there. If someone knew the process that was in place to be able to hide this information, they would very easily be able to retrieve that information that was obfuscated.

And because of that, we refer to this as security through obscurity, because this is not a true secure method. Although this message is invisible to the human eye, there really is a message inside of the image. We refer to the container that has this message inside of it as the cover text.

So in this example, the graphic that’s used on this particular view is the cover text. And inside of that graphic is some additional details. And if you knew how to extract that information from the file, you would be able to gather a list of IP addresses, names, and MAC addresses that are hidden from the human eye but do exist inside of that image file.

There are a number of steganography tools that you can download and use as open source that are able to store information in images. You can then send that image to someone else. And they can use a similar steganography program on their side to extract this information from the image.

There are a number of different ways to hide information using steganography. One is based on the packets going across the network. If you can add some additional bits of information to these network packets, you can collect those bits on the other side. And now you can put together information that no one had any idea was being transmitted that way.

As we’ve also mentioned, you can use an image to be able to transfer this information– and the larger the image, the more information you’re able to transfer. And if you examine the output from a laser printer, you’ll notice there are watermarks on every single page that provide information on the laser printer and where it may be located. If I reverse the image, you can see the dots are a little bit easier to read. And the structure and makeup of these dots provide other people with information about this particular printout and which printer this came from.

Steganography, of course, is not limited to just images. You can store information within audio files. So you could put documents, spreadsheets and other types of data within an audio file, send that audio file to someone else, and they could extract all of that information on their side. Very similarly, you can do the same thing with a video file– the larger the file, the more information you can store. And so video steganography allows you to store quite a bit of information– send that entire video to someone to transfer all of that information at once.