Thread: Spy Stoper

Spy Stopper

Privacy in the workplace is very iffy. Most offices have a network computer system, and it might be that your colleague in the next cubicle has enough know-how
to sneak in through an open port in your PC. Well, stopping this sort of activity
is easy. If the PC has the Windows Firewall enabled, access it from 'Start I Run' and type 'firewall.cpl' in the Open field. Switch to the 'Exceptions' tab and check which ports are unblocked under the Programs and Services list. Delete those entries which are not absolutely necessary, close the window and press 'OK'. If your machine runs a third-party firewall, it can be used to blocked open ports too.

Another simple method to hide your documents is to set Windows to stop displaying recently opened documents in the Start menu. Simply right click on-the Start button and choose Properties from the context menu. Switch to the 'Start Menu' tab and click 'Customize'. Under the Advanced Start menu options, check the boxes under Recent Documents menu. Thrs will ensure that people who stop by your workstation to take a quick look around won't stumble across some sensitive information.

MASK YOUR FILE

Just pick an innocuous photo from your previous vacation trips, and we will show you how to hide your personal file in it. The casual observer won't see beyond the palm trees and ocean, and notice that there is something hidden in the image. Only someone who knows that there is, say a PowerPoint presentation, hiding in there will be able to access it using a combination of decryption and password. This method
of hiding information in multimedia files is called steganography, where the data
is stored in the multimedia file in such a way that the file still appears and works
as a normal multimedia file. The trick used here is that only the last bit of a
byte block is modified, leaving the rest of the block unchanged, and this is exactly how the secret file can be hidden in the multimedia file, bit by bit.

There are plenty of applications out there that do this, the most famous of which is Steganos Privacy Suite. Home users may turn to freeware. We found the program 'wbSteg04' downloadable. It hides data in bitmap images, ASCII and ANSI text files, HTML PDF files and runs in two modes-Flowchart, which is for advanced users, and the default Wizard mode for beginners. Install it on your machine, and pick the secret file and an image. Press the 'Continue' button from the first step of the wizard, and then select 'Encode'. Next, enter the folder path and filename of the data file, click 'Continue' and specify the carrier file name and folder path and move on the fifth step. Now, press 'Cryptography settings' and set an encryption method, for instance, 'Blowfish' and specify a password and press 'OK'. Then, enter the
filename and folder path for the target file and finish the wizard. The output bitmap image, in our case, was no different than the original. It was the same size, 154
KB, and could be viewed in the Windows Picture Viewer without any problems, thereby leaving no room for suspicion.

To retrieve the hidden file, choose 'Decode' from the main application window, specify the encoded file and its password, and enter the target filename and folder path. After decryption, you should be able to view the hidden file.

Though 'wbSteg04' doesn't support ZIP files, there are many other choices
in the freeware market that can be used, such as OpenStego available on openstego.sourceforge.net. Download the program (ZIP file) from the official website, extract it to a folder, and double click on 'openstego.bat' to run the application. Set the Message file as the compressed file, and specify the Cover file and Output Stego file.



CONCEAL A ZIP

The main drawback of 'wbSteg04' is that you require it to decode the hidden data. So, even if a user sends the masked file over the Internet
to another user, the recipient will need to have the same program installed on his machine to read the data in its original form. To avoid this pitfall, it is better to cache the secret file using. a compression tool like 7-Zip into a standard Windows compressed format ZIP.

The advantage of using a compressed ZIP file is that it is widespread and can be opened by any compression program, be it a shareware application like WinZip or a freeware tool, such as PeaZip. And here's how it is done: install the compression tool 7-Zip on your PC from this issue's DVD. This is where the command line comes into the picture. Open up the command prompt from 'Start Run. Now, pick out the secret file and a BMP image file, and enter the following command at the prompt.

Here, 'image.bmp' and 'secretfile.txt' refer to the message file and cover file respectively. Windows creates the 'new. bmp' file and stores it in the same folder as its input files. Later, when this resultant image is viewed, users will see just a normal photo.

Normally, the size of the file doesn't matter; you can hide a 100 MB video in
a 30 KB image. However, the new file requires a s'torage space equal to that of the JPG and the hidden file combined. So, if an image file is unusually large, then it will immediately strike strangers that the image may contain hidden information.

Right click the masked fi.le and choose 'Add to archive' from the context menu. Set the compression format to ZIP, input a password and encryption method, and finish the compression process. Thus, the recipient can uncompress the file using any tool, and when the masked file has been extracted, change the file extension to 'txt'. When this 'new.txt' file is open in Notepad, the original text will be visible at the latter end of the file.

NOTE

If Windows does not show file extensions, open Windows Explorer,
go to 'Tools I Folder options I View' and uncheck the box for the option 'Hide extension of known file types' and click 'Apply'. You can always restore default settings after changing the file extension.

CACHE WITH NOTEPAD

If you can't install programs on the PC, Windows provides a standard tool to hide text and information in a normal file. All you need is Notepad. Open the command prompt and enter.

An error box will inform you that this file does not exist as yet and ask if you want to create it. Confirm by clicking the 'Yes' button. Enter some random text and save the file. Here's a trick go back to the command prompt and enter.

The error message reappears, so press the 'Yes' button and enter random text again. When you browse to the folder location using Windows Explorer, the file will not appear in the window.

So, if you need to reopen the file, you will have to use the same command line prompt again. The only hitch to this method is that if you forget the path and the file name, the file is lost-it can neither be moved nor mailed.