Visual Cryptography

November 20, 2013 | Cryptography, My Projects | By: Mark VandeWettering

I read an interesting article the other day. I’ll skip to the end to show you the result. Check out this pair of binary images:



Not too fascinating, huh? If you print both images out on transparency though, and stack them together, you’ll get this…


Hopefully that worked (with my limited CSS skills, I don’t think I got it exactly right). I couldn’t get the CSS exactly right, so the above image is really just the pairwise minimum of both images above. But how I accomplish this miracle? My own simple python implementation of the ideas cribbed from this page. Script to come later.


Comment from Jim Atkinson
Time 11/23/2013 at 11:34 am

Apparently also the pear wise minimum.

Comment from kiwimonster
Time 12/2/2013 at 9:22 am

looks a lot like some of our early attempts at raytracing (circa late 1980’s) – dithering to a laser printer.

Comment from m0n5t3r
Time 4/17/2014 at 4:33 am

superimposing the images in CSS would be as simple as style=”background: url(img2.png)” 😉