Introduction
This Project Titled “Data Hiding in Audio, Image and Video files” is the software developed for hiding information which uses the technology called as Steganography –derived from the Greek words meaning, “Covered writing”, is the art of hiding information in ways that prevent its detection.
It is a method akin to covert channels, and invisible links, which add another step in security. A message in cipher text may arouse suspicion while an invisible message is not. Digital stenography uses a host data or message known as a “Container” or “Cover” to hide another data or message in it. The conventional way of protecting information was to use a standard symmetric or asymmetric key system in encryption. Steganography can also be used to place a hidden “trademark” in images, music, and software, a technique referred to as watermarking.
To ensure the privacy of the communication between two parties, various new methods are being developed. Cryptography being the mother to all those projects. However, cryptography is like a tool, it can do as well as it is programmed to do. Also, there are various different techniques that can be implemented to attain a certain level of security. Here we implement a technique for data hiding in audio images, known as Audio file Steganography.
First the audio file which behaves as carrier file is selected. Then a message or a text file to be embedded in audio is selected. Then a key file is selected. The key file contains characters whose ASCII values are taken for encryption. Then the file is embedded in audio using low bit encoding mechanism and extraction of embedded message is being done vice-versa.
We are of the belief that the easiest way to keep something from prying eyes is to place it right in front of the person looking for it and make it look as innocuous as possible.
Everyone has a taste for a certain kind of music. Hence, it is more than likely that the person will have that kind of music on the storage device of his computer. Also, it is quite common case where people share and transfer different music files to one another. If one were able to hide the message can be. Also, transfer of this message can be done quite conveniently without raising any eyebrows.
Our aim is to come up with a technique of hiding the message in the audio file in such a way, that there would be no perceivable changes in the in the audio file after the message insertion. At the same time, if the message that is to be hidden were encrypted, the level of security would be raised to quite a satisfactory level. Now, even if the hidden message were to be discovered the person trying to get the message would only be able to lay his hands on the encrypted message with no way of being able to decrypt it.
STEGANOGRAPHY IN MP3
Data hiding in audio signals is especially challenging, because the Human Auditory System (HAS) operates over a wide dynamic range. The HAS perceives over a range of power greater than one billion to one and a range of frequencies greater than thousand to one. Sensitivity to additive random noise is also acute.
The perturbations in a sound file can be detected as low as one part in ten million which is 80dB below ambient level. However there are some ‘holes’ available. While the HAS has a large dynamic range, it has a fairly small differential range. As a result, loud sounds tend to mask out the quieter sounds.
Additionally, the HAS is unable to perceive absolute phase, only relative phase. Finally there are some environmental distortions so common as to be ignored by the listener in most cases.
