CALEB WALTER 7/14/2013 Audio Stego – A Brief How To.

CALEB WALTER7/14 /2013

Audio Stego – A Brief How To

What is Audio Steganography?

Hiding Data inside Audio files (WAV, MP3, WMA, etc)

Digital Audio differs from Analog Audio Continuous Signal vs Discrete Signal Sampled at a continuous rate (CD: 44Khz)

Data is hidden by slightly changing the discrete signal to remain inaudible

Encoding Data in Audio

Multiple Tools to encode audio into MP3 file and format MP3Stego – Takes a .TXT file and .WAV File and

Encodes and formats into a MP3 File Coagula – Encodes an Image into an MP3 or .WAV File

Encoding with MP3Stego

Create a sample .TXT file with your desired encoded message

Save this Desired Message into the Same Folder as your .WAV

MP3Stego Encoding Cont.

Find Desired .WAV File (I chose Classic Mr.T) Make Sure it is in the same Directory as the

Earlier .TXT FileLoad up MP3Stego GUI

Select “Encode TXT file in an MP3 File”

Encoding with MP3Stego Cont.

Select your Desired Encoded Message in “Select Original TXT File” box

Select your chosen WAV file to encode in “Select Original Sound File” box

Type the desired name of your newly encoded MP3 in the “Output File” box

MP3Stego Encoding Cont.

Press “Encode File!!!” Button to begin Encoding

To enter a password to protect against random decoding, type desired Password into box You will not see the text you type, so make sure you

get it right!

Encoding with MP3Stego

After Pressing Enter and confirming any desired passphrase, an Encoded MP3 File will be saved into the same directory as the .WAV and .TXT

Encoding with Coagula

Create an Image with your preferred Image Creation/Modulation Software I chose Paint A Small Image without much empty space will work

best

Encoding with Coagula

Open up Coagula and go to File: Open ImageFind your created image in the directory and

press Open

Encoding with Coagula

Either go to the Sound Drop down Menu and press “Render without Blue” or Press the button with Green and Red gears to render the image as sound

Newly Encoded .WAV file will be saved as Coagula.wav in Coagula Directory

Decoding with MP3Stego

Open Up MP3Stego and Select “Decode TXT File from an MP3 File”

Select your Encoded MP3 File from before and in “Select MP3 to Decode:” box

Decoding with MP3Stego

Enter in any established passphrase for your file within the Passphrase box

Press Enter and a .TXT file bearing the name of the encoded MP3 file will appear in the directory

Decoding with Sonic Visualizer

Open Up Sonic Visualizer and open the encoded .WAV File into the Visualizer You will only see Audio Spectrum for now

Go to Menu and press “Add Spectogram” For this application any and all submenu options will

have no effect

Future Methods for Audio Steganography

Echo Hidden – Echo Inside Audio File, hiding data within the echo so that it is undeterminable to the human ear

Song Filtering – Running multiple FIR filters over a song to encode data into it, without changing the sound or file size

Sources

http://www.findsounds.com/ISAPI/search.dll?keywords=boing+spring+springy

http://lifehacker.com/5807289/how-to-hide-secret-messages-and-codes-in-audio-files

http://www.abc.se/~re/Coagula/Coagula.html?Download=Latest