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:

img1

img2

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

both

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.

Comments

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)” 😉