Niels Horn's Blog

Hidden name in the Linux logo

October 19th, 2008 by Niels Horn in Linux, Tux, gimp, steganography

This is what makes computing fun - you learn something new every day.

Today there was a post on LinuxQuestions.org by w1k0, who reported something strange with the Linux logo on his ThinkPad T60. The colors were all wrong (Tux had a green belly, blue background) and… to the left-side there was an inscription saying "Simon".

I suggested checking the vga-setting in lilo, but was intrigued by this mysterious inscription.
I am familiar with the history of the Linux logo created by Larry Ewing and the vectorized version by Simon Budig, so I thought of the possibility of a hidden text in the bitmap.

I opened the logo (the standard 224-color version is called logo_linux_clut224.ppm), which can normally be found in /usr/src/linux/drivers/video/logo/, in the gimp.

And I found nothing. So I already started thinking that someone was pulling a joke on w1k0 and had messed with his kernel. But that seemed weird… This someone would have to compile a new kernel, just to get a green-bellied penguin with the name Simon at boot-time.

Then I thought of steganography and how this inscription could be hidden. Since it showed up (with the wrong color) on w1k0's screen, it must be of a color almost equal to the background.

So I opened the logo in the gimp again, clicked on the color-selection tool and changed the 'limit'-setting to 0,0. Then I clicked on a random spot on the black background and Bingo!
There really is a hidden inscription in the Linux logo!

To make it visible, I painted the pixels red and enlarged the bitmap.
The result is here, but do check it out on your own file!