（ ）is the science of hiding information. Whereas the goal of cryptography is to make data unreadable by a third party. the goal of steganography is to hide the data from a third party. In this article, I will discuss what steganography is, what purposes it serves, and will provide an example using available software.
There are a large number of steganographic （ ）that most of us are familiar with (especially if you watch a lot of spy movies), ranging from invisible ink and microdots to secreting a hidden message in the second letter of each word of a large body of text and spread spectrum radio communication. With computers and networks, there are many other ways of hiding informations, such as:
Covert channels (c,g, Loki and some distributed denial-of-service tools use the Internet Control （ ）Protocol, or ICMP, as the communication channel between the “bad guy”and a compromicyed system)
Hidden text within Web pages
Hiding files in “plain sight”(c,g. what better place to “hide”a file than with an important sounding name in the c:\winnt system32 directory)
Null ciphers(c,g, using the first letter of each word to form a hidden message in an otherwise innocuous text)
steganography today, however, is significantly more （ ）than the example about suggest, allowing a user to hide large amounts of information within image and audio. These forms of steganography often are used in conjunction with cryptography so the information is double protected; first it is encrypted and then hidden so that an advertisement first. find the information ( an often difficult task in and of itself) and the decrypted it.
The simplest approach to hiding data within an image file is called （ ）signature insertion. In this method, we can take the binary representation of the hidden data and the bit of each byte within the covert image. If we are using 24-bit color the amount and will be minimum and indiscriminate to the human eye.
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