SteganoGraphy--The Art Of Hiding Data Within Files..!!

What does Steganography mean?

                        Steganography is the practice of concealing a file, message, image, or video within another file, message, image, or video. The word steganography combines the Greek words steganos  meaning "covered, concealed, or protected", and graphein meaning "writing".

so what?

Steganography is data hidden within data. Steganography is an encryption technique that can be used along with cryptography as an extra-secure method in which to protect data.

Historical Methods of Steganography:-

                                           In ancient Greece, people used to write on wax-covered tablets. The first documented occurrence of steganography was in the document The Histories of Herodotus, when Demeratus sent a secret message past guards by removing the wax from the tablet, writing on the tablet itself, and covering the tablet with wax again to disguise the message. Invisible ink is a form of steganography used in recent centuries.

                                                     Another form of steganography is in null ciphers, or unencrypted text messages. For example, one could hide a text message within a paragraph of words, so that by isolating every 10th word, the secret message can be detected .The paragraph itself would sound innocent to escape detection. This form of steganography was often used in wars among spies.

                                                 Recently, computerized steganography has become popular.Using different methods of encoding, secret messages can be hidden in digital data, such as .bmp or .jpg images, .wav audio files, or e-mail messages. These methods are described below. Authors are able to watermark their property in this manner. Unfortunately, steganography is also suspected to play a role in the communication among terrorist groups around the world.In the past year, several suspected that Osama Bin Laden may have been posting images on Ebay with hidden messages inside to send to different terrorist groups. Recent attempts to detect the presence of such images on Ebay have not uncovered anything, though.

Uses:-

                             Steganography techniques can be applied to images, a video file or an audio file. Typically, however, steganography is written in characters including hash marking, but its usage within images is also common. At any rate, steganography protects from pirating copyrighted materials as well as aiding in unauthorized viewing.