Steganography

Steganography Workshop

1. Download S-Tools. An alternative product if you are using Mac OS X is iSteg (iSteg supports JPG files only), and the instructions below are only for the Windows tools.

2. Create a folder in the "My Documents" Folder - You may wish to call it stego exercise or something similar 3. Open the S-Tools.zip file 4. Drag all of the files into the folder in the "My Documents" folder you created in step 1. 5. Run the program by double-clicking on the s-tools.exe icon.

1. This will open the s-tools program window. 2. In the next step you will navigate away from this window, but leave the window open, as you will need to switch back to it in a

few minutes. 6. Find a .GIF image file using Google's Image search, selecting a .GIF image of your own or use this picture of Tux. (Only .GIF files,

please) 1. Save the image to your folder in the "My Documents" folder

7. Create a text file called cgs3559-YOURNAME.txt - ONLY USE Notepad DO NOT use Word or another word processing program. Notepad can be found under Start | All Programs | Accessories

1. In the text file, place your name, your Panther ID, and some message like your favorite quote or saying. 2. Be sure to save the file.

8. Download WinMD5Sum. It should save as winMd5Sum-install.exe. Mac OS X users, please use the command-line tool md5 (a guide is available here).

9. Install WinMD5Sum by double-clicking on the winMd5Sum-install.exe icon. Accept the default installation options. 10. Run WinMD5Sum.

1. Click on the Start menu 2. Click on All Programs 3. Highlight the WinMD5Sum Folder 4. Click on the WinMD5Sum Program Icon.

11. Calculate the MD5 sum of your image 1. To calculate a sum

1. Run winMD5Sum 2. Open the file explorer window (Right click on Start and select Open) and navigate to your folder in "My Documents" 3. Drag the filename of the image you selected in step 6 and drop it on the WinMD5Sum Program window 4. The second box, MD5 Sum will then display a long alphanumeric sum

2. Open a new Notepad or Word file and save it as "YOURNAME SUM.txt". 3. Highlight and copy the calculated sum from the program window (the number in the 2nd box) and put it in the new document.

12. Now, hide your text file in your graphic, calling the new file YOURNAME.IMAGEFILENAME.gif, e.g. TimWalker.tux-hidden.gif 1. Go back to the s-tools windows that you left open in step 5 2. Drag the image you want to hide information in, from the folder you created and drop it onto the S-Tools program window. 3. Drag your text file onto the S-Tools Program Window, dropping it on the already open image.

DO NOT drop the text file into the S-Tools Program window, you must let go on the window containing your image. 4. You should then see a dialog box asking for a passphrase and encryption algorithm. Use your PANTHER-ID as the passphrase.

(This is a password/key for the encryption taking place behind the scenes) NOTE: If you use the image of Tux from this page, you may get another dialog warning about color depth changes, take the default (just say ok).

5. When the text is hidden a new window will open showing your image, called "Hidden". To save it, right-click on the "hidden" window and save the file as YOURNAME.IMAGEFILENAME.gif, e.g. TimWalker.tux-hidden.gif

6. You should now have two image files in your "My Documents" stego exercise folder. One is your original image and the other is your image with the hidden message.

13. Calculate the MD5 sum of your new file 1. To calculate the sum of the hidden image, run winMD5Sum, drag a file and drop it on the WinMD5Sum Program window 2. You can highlight and copy the calculated sum from the program window. 3. Put this sum on another line in the file that created in step 11

14. Look at the two graphic files in your Web brower or an image editing program. Can you tell that the file has been altered? You might notice a slight change in file size. The image size may increase by 1 or 2 KB.

15. Create a ZIP file containing your two graphics files, the sum file, and your text file, and put them in the drop box. 1. Right-click in the folder you created, select New, then "Compressed (zipped) folder" 2. Give the file a name and press enter, such as YOURNAME-stego.zip. 3. Drag your four files onto the compressed file and drop to add them