Steganography is a means to hide data where secret messages are hidden within computer files such as images, sound files, videos and even executable files so that no one but the sender and receiver suspect the existence of sensitive information in it . Steganography may also involve the use of cryptography where the message is first encrypted before it is hidden in another file. Generally, messages appear to be something else, such as an image, sound or video, so the transfer of secret data remains unsuspected.
The main advantage of steganography over other methods like cryptography is that, there will be no suspicion even if the files fall into the hands of a third party. Unlike cryptographic messages, stegnographic messages do not attract the attention of a third party by themselves. Therefore, stegnanography has an advantage over cryptography, since it involves encryption and darkness.
What are the applications of steganography?
Steganography is mainly used to hide sensitive information / data during storage or transmission. For example, you can hide a secret message in an audio file and send it to another person by email instead of sending the message in textual format. The receiver at the other end will decrypt the hidden message using the private decryption key. In the worst case, even if a third party manages to access e-mail, all you can find is the audio file and not the hidden data inside it. Another use of steganography includes digital image watermarks for reasons such as copyright protection.
Although steganography has many useful applications, some may use this technique for illegitimate purposes, such as hiding pornographic content in other large files. Rumors are also reported about terrorists using steganography to hide and communicate their secret information and instructions. An article claiming that Al Queda had used steganography to encode image messages and transport them by email was reported by the New York Times in October 2001.
How do steganography tools work?
Stegnography tools implement intelligent algorithms to carefully embed encrypted text messages or data into larger files such as an image, audio, video, or executable file. Some tools will incorporate the encrypted data at the end of another file so that there is enough space to store larger data.