Things are not always what they seem

The image above is not simply a portrait of David Hume (1711-1776). Strange enough, it also contains one of his most significant essays: "IDEA OF A PERFECT COMMONWEALTH" (7 pages).
The text is hidden in the picture by means of a procedure known as "steganography". Files of any type can be hidden in images and sounds (files of the types *.bmp, *.tif and *.wav).
Your browser possibly displays an empty frame instead of the picture. Some browsers are unable to display images of the type "*.bmp" or require a special plug-in to do so.

To reveal the hidden contents, the following steps are necessary:

• Store the image (file hume.bmp) in any folder (using the right mouse key).
  In the case of your browser being unable to display images of this type, please click here for download.
• Download  "stegane.exe" , best into the same folder. The size of the file is  43 KB. You may take for granted, that the file is free of viruses.
• Start "stegane.exe.
  The program requires Windows 95 or higher.

• Select option "Unload".

• Follow the guidance by the program menu.

If you are going to hide your own data (files of any type) in your own carrier files (type: *.bmp, *.tif or *.wav), please note that the designated carrier file should be at least 8 times as large as the "payload" file to be hidden. The reason is, that the algorithm never toggles more than one bit in a byte of the of the carrier file. The program will recognize a carrier file too small, however, and abort with an error message.

A short test report by eMail would be appreciated!

Yours sincerely
Erwin Schwendike

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