Ever
wondered to know how to hide secret messages in images, audio and video
files? Well, in this post I will take you through a concept called steganography using
which, it is possible to hide your secret information in image
files, songs or any other file of your choice. At the end of this post,
you can also download free stegnographic tools and start hiding your
data.What is Steganography?
Steganography is a means of obscuring
data where secret messages are hidden inside computer files such as
images, sound files, videos and even executable files so that, no one
except the sender and the receiver will suspect the existence of stealth
information in it. Steganography may also involve the usage of
cryptography where the message is first encrypted before it is concealed
in another file. Generally, the messages appear to be something else
such as an image, sound or video so that the transfer of secret data
remains unsuspected.
The main advantage of steganography
over other methods such as cryptography is that, it will not arose
suspicion even if the files fall in the hands of a third party. Unlike
cryptographic messages, stegnographic messages will no way attract the
attention of a third party by themselves. Thus stegnanography has an
upper hand over cryptography as it involves both encryption and
obscurity.
What are the Applications of Steganography?
Steganography is mainly used to obscure
confidential information/data during storage or transmission. For
example, one can hide a secret message in an audio file and send this to
another party via email instead of sending the message in the textual
format. The receiver on the other end will decrypt the hidden message
using the private decryption key. In a worst case scenario, even if
a third party does manage to gain access to the email, all he can find
is the audio file and not the hidden data inside it. Other usage of
steganography include digital watermarking of images for reasons such as
copyright protection.
Eventhough steganography has many useful
applications, some may use this technique for illegitimate purposes
such as hiding a pornographic content in other large files.
Roumors about terrorists using steganography for hiding and
communicating their secret information and instructions are also
reported. An article claiming that, al-Queda had used steganography to
encode messages in images and transported them via e-mails, was reported
by New York Times, in October 2001.
How do Steganography Tools Work?
Stegnography tools implement intelligent
algorithms to carefully embed the encrypted text messages or
data inside other larger files such as an image, audio, video or an
executable file. Some tools will embed the encrypted data at the end
of another file so that there will be enough room for storing larger
data.
There are many steganography tools
available online but only a few are able to work flawlessly. I did not
find any tool that worked perfectly on both small and large
data. However I have managed to develop my own tool that can work
perfectly on all types of files and all size of data. The tool is called
“Stego Magic“. You can download it from the following link.
The zip file contains two versions of Stego Magic: One for encrypting the text messages and the other for encrypting binary files. StegoMagic_TXT can be used to hide text messages in other files such as an image or a sound file. StegoMagic_BIN can be used to hide one binary file in another such as an executable file inside an image or an image inside a video file.
With Stego Magic, there is no
limitation on the size and type of the file that you are intending to
hide. For example, you can hide a video of size 1 GB in an image of size
1 MB or hide an executable file inside a WORD document. The tool is
pretty straightforward to use and requires no special understanding of
the concept.
At the end of the encryption process, a
secret decryption key will be generated and the same is required during
the decryption process.
How to Use Stego Magic?
Suppose you want to hide a text message inside a JPG file:
1. Place the JPG and the text file (.txt) in the same folder as that of StegoMagic_TXT.exe
2. Run StegoMagic_TXT.exe and follow the screen instructions to embed the text message inside the JPG image.
3. Note down the secret decryption key.
Now you can send this image to your
friend via email. To decrypt the hidden message, your friend should load
this JPG file onto the Stego Magic tool and use the secret decryption key.
I hope you enjoy this post 
. For queries and feedback, please pass your comments 
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