Steganography is the practice of hiding a message in a place where nobody would think to look. Generally, a steganographic message will appear to be something unassuming, like a picture, an article, a shopping list, or some other message. If you don't know where to look, you will not even know that a secret message has been hidden.
It may be hidden by using invisible ink between the visible lines of innocuous documents, or even written onto clothing. Another method simply pin pricking of individual letters in a newspaper article, thus forming a message. It may even be a few words written underneath a postage stamp.
The advantage of steganography over cryptography alone is that messages do not attract attention to themselves, to messengers, or to recipients. An unhidden coded message, no matter how unbreakable it is, will arouse suspicion and may in itself be incriminating.
Examples of Steganography
Invisible InkConcealing messages within the lowest bits of a digital image.Chaffing and Winnowing - Sending multiple conflicting messages, where the recipient has some method of identifying the true message.Tattoo a message on someone's head and then let their hair grow back. Used in ancient Greece.Microdots - Text is written so small that a microscope is required to read it.
