Rating: 3.0

# IceCTF 2016 – Pretty Pixels

## Problem

>Don't get me wrong, I love pretty colors as much as the next guy... but what does it mean?

## Solution

If we preview the image, it is just pure multicolored noise.

mathematica
image = Import["https://play.icec.tf/problem-static/pretty_pixels_604e889db44de75ea4541a23e344b80eb315f0faf4136abc6d40e1fff8802c9f.png"]


![pretty pixels](pretty_pixels_604e889db44de75ea4541a23e344b80eb315f0faf4136abc6d40e1fff8802c9f.png)

We want the values for each pixel. We could use ImageData[image,"byte"], or we can specify "Data" when downloading the image to get the byte data of each pixel.

mathematica
imageData =
Import[
"https://play.icec.tf/problem-static/pretty_pixels_604e889db44de75ea4541a23e344b80eb315f0faf4136abc6d40e1fff8802c9f.png",
"Data"];


Lets try to interpret the first 100 pixels (300 RGB values) of the image as ASCII bytes.

mathematica
FromCharacterCode[Flatten[imageData][[;; 300]]]



PNG

IHDR& s(bKGDÿÿÿ ½§ pHYstIMEà"Wÿ0fEiTXtCommentCREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 80
f_-w IDATxÚÌ½yåuy5~ºûÞ¾{ßÞféÙÑP,3FË Á*XI¦"(¸U¢|Q4j¢&Æ1hX¢BXYmgÆÙ^nßýö½}û/ïùüÎ}æùÜnß¼oÅ®¾Ë/ûù~ó


That looks like the PNG header. Let's interpret pixel of the image as bytes and convert it into a string of binary data. Then use ImportString[] to import the data as if it were a file of binary data.

mathematica
ImportString@FromCharacterCode@Flatten@imageData


![flag](flag.png)

Original writeup (https://github.com/bburky/mathematica-ctf-writeups/tree/master/Pixel%20data).