Steganographic methods are numerous. We see examples in spy movies and novels like invisible ink, microdots and plain cyphers. It seems only natural then that this covert means of sending messages would migrate into the cyber world of computers.
Computer technology opened up a whole new avenue of hiding messages using the hidden code on a page. In fact using the electronic means of communication as most of us do, messages can be hidden within Web pages, images and online video and audio.
The term Steganography comes to us from the Greek-steganos (covered or protected) and graphei (writing). Cryptography (hidden-writing) is a term we are much more familiar with. But the two terms mean pretty much the same thing…and the terrorist element has learned how to use it.
USA Today reported a while back that (the late) Osama bin Laden and others “are hiding maps and photographs of terrorist targets and posting instructions for terrorist activities on sports chat rooms, pornographic bulletin boards and other websites, U.S. and foreign officials say.”
This technique is a practice of embedding secret messages in other messages — in a way that prevents an observer from learning that anything unusual is taking place. Encryption, on the other hand, relies on ciphers or codes to scramble a message in plain view.
Forensic cyber specialists cite the advantage for the “dark side” employing steganographic techniques. It should be noted that encrypted messages in plain sight-even if they are indecipherable-attract attention. Thus, steganography protects both the encrypted message but also the people sending and receiving them.
Steganography now includes the concealment of information inside of computer files, but in digital steganography, such communications may include coding inside of a carrier, like a Word file, photographic file, and even software programs. Media files present the ideal platform for steganographic encoding mainly because of larger file sizes. As an example, a sender might start with an ordinary downloaded family photograph and manipulate the color of every so many pixels to correspond to a letter in the alphabet. This change is so subtle that someone not specifically trained to look for it is unlikely to see it.
I recently saw a stunning example of encryption that began with an image of a line of treetops, but hidden within this photo was a shot of cat curled up on a colorful blanket. We must never underestimate the abilities of those hell-bent on destroying us. Chances are that the very cryptographers plying this trade were educated right here in some of our finest U.S. universities.
Steganography is a really an interesting subject and it is outside of the common cryptography and system administration that most of us deal with day after day. But it is also quite real; this is not just something that’s played with in the lab or some off-the-wall subject of study in academia. This threat may, in fact, be all too real – there have been unconfirmed reports that the terrorist’s behind the September 11 attacks used steganography as one of their means of communication.