Project #5 Anti-Surveillance Tool

Description

The first time I knew about Steganography is when I was at primary school and the book Tiger Team Series was very popular back then. One special thing about Tiger Team is that every chapter ends with one question and a hiding secret answer. Readers can use a particular detective card to read the secret message. I thought it was amazing, and I realized now this was made with Moiré pattern. Moiré pattern is the visual result of interference between two lines or two objects at a constant angle and frequency. When the human eye cannot distinguish these two lines or two objects, only the interference pattern can be seen.

And my assignment is tribute to the Tiger Team! I used their classic way to hide the message with Moiré pattern.

Strategy

I used the nested for loop to cread 4 parts. Atually I only hided 2 messages in this sketch, because my computer somehow sounds like it will soon explode when I run the code. For the first message, I put a bunch of lines and cover the original information. Then I created the "detective card" with lines vary with the mouse, everytime it coincide with the cover, the message can be seen more clearly.

For the second message, I used the technique I learned from the tutorial 5.2.2 blendMode() + Loops - Anaglyph Illusion. When the whole page is covered by the blue lines, the blendmode(MUTIPLY) will reveal the second message.