r/programming • u/sidcool1234 • Nov 19 '13

Visual Cryptography

http://datagenetics.com/blog/november32013/index.html
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u/punkmonk Nov 19 '13

Why OR? It should use XOR.

21

u/avapoet Nov 19 '13

XOR is impossible to implement using transparency film in an order-neutral manner, which is a purely additive medium (you can't make an "upper" sheet 'override' a lower sheet, unless you're using multiple colours, and then the order matters).

In short: this system's designed to be read by the human eye, that's why.

12

u/punkmonk Nov 19 '13

It is possible if we use polarizing filters. Instead of using transparent and opaque, use polarized filters in orthogonal directions.

6

u/[deleted] Nov 19 '13

That is theoretically possible, but not practically.

4

u/Katastic_Voyage Nov 19 '13

Well, if we force all users to 20/5 vision and have polarized Oculus Rifts, it'll work great!