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Stego PNG

Software to Encrypt and Hide a Data File
in a PNG or a BMP Image File

Hermetic Systems

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Compatible with Windows 7
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Graphic images are contained in files using various file formats, the most common being GIF, JPG, BMP and PNG (an acronym of "Portable Network Graphics"). Stego PNG is a Windows program for hiding a data file in a single PNG or BMP image file and for extracting a data file hidden in this way. The file may be of any kind, not just a text file, and thus may be a file such as an MS Word document, an Excel spreadsheet or another image file.

This steganography software inserts data in the image file in a random way depending on a key (which is also used to encrypt the data), and changes other bits of the image file to compensate for the modifications induced by the hidden data so as to avoid modifying statistical properties of the image file. It is thus more secure than most steganography programs.

Stego PNG has a simple user interface and is easy to use. Here is a typical screenshot, after hiding a file:

Stego PNG screenshot

The original and stego images will be displayed after the hiding operation if the checkbox for this is checked.

You can toggle between green and gray by double-clicking on any part of the window which is not a control.



The art or science of hiding information is named steganography. In one form or another steganography has been practiced since ancient times. With the development of computers it has become possible to hide the contents of a computer file (the data) in another file (the container file) so that the insertion of the data file into the container file will not noticeably change the properties of that file (or the appearance of the image, if the file is an image file). If the file which has been hidden is deleted (preferably using a secure deletion program such as Data Destroyer) then there is no indication that it even exists, but it can still be recovered when you need to get at it.

Good candidates for container files are graphics images, since it is possible to make small changes to the bytes specifying pixel color values in such a way that the "stego" image (containing the hidden data) does not look any different from the original image (the one which does not contain the hidden data).

Stego PNG allows you to hide a file of any type in a PNG or a BMP image file, with the use of a user-specified stego key (an encryption key), so that (i) the presence of the hidden file is undetectable (even by forensic software using statistical methods) and (ii) that data can be extracted only by someone who knows that stego key.

A stego image (that is, an image containing hidden data) can be displayed in a web page (from where it can be saved by any viewer to disk) or sent to another person as an email attachment. If one simply wishes to hide sensitive data (such as a file containing passwords, bank account details, etc.) on one's computer, there are normally plenty of BMP files to be found there, and often also plenty of PNG images from web pages which have been saved. (Note that not all web browsers can display all PNG images correctly; Firefox, Chrome and Opera can, but Internet Explorer up to Version 8 cannot.)

Two more uses for Stego PNG are: (i) To add a 'watermark' to an image file. (ii) To transport sensitive data (e.g., information in an Excel spreadsheet) without detection. You can hide the data in a PNG or BMP image and put that image on a memory stick (a.k.a. flash drive or pen drive); having safely reached your destination you can then extract the data from the image.

A BMP file containing a particular image is significantly larger than the PNG file containing the same image. For this reason BMP files are not normally included in web pages (which usually have GIF, JPG or PNG images). If sending an image file as an email attachment the file can first be ZIPped up to reduce its size.

Stego PNG differs from some or all other steganograpy software in two respects: (i) A stego/encryption key is required to ensure that only someone who knows the key can extract data hidden with the use of that key.  (ii) The bits of the data are inserted into the bytes of the image files randomly (based on the stego key) and in such a way as to defeat the use of statistical tests to reveal the presence of hidden data.


Stego PNG User Manual



Virus-free Trial version: A copy of the Stego PNG installation program is available for free download from this website for the purpose of installing a trial version for evaluation. Click on the following link for further information:

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Price and ordering: The price for a single-user license is given at Purchase a User License. (A multiple-user license is available for this program.) An activation key is required in order to make the trial version permanently fully functional. An activation key can be obtained immediately if you purchase a user license either via PayPal or via Share-it.

Refund: A refund will be provided promptly up to 30 days after purchase if the software does not perform satisfactorily.

Updates: Purchasers of a user license for this software are entitled to an update to any later version at no additional cost.

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