Rating:
# picoCTF Pixelated Write Up
## Details:
Points: 200
Jeopardy style CTF
Category: Cryptography
Comments: I have these 2 images, can you make a flag out of them? scrambled1.png scrambled2.png
## Write up:
I decided to open these files up using PIL to play around a little. Xor'ing the various pixels together I noticed that most of the xor values ended up being 255,255,255.
I then wrote a python script to xor all the values together but the photo was mostly white with a little but of blue in it. I then decided that everything that was pure white should be turned black:
```python
# import Image
from PIL import Image
# open both photos
i1 = Image.open('scrambled1.png')
i2 = Image.open('scrambled2.png')
# get width and height
width1, height1 = i1.size
# open new image
i3 = Image.new('RGB', (width1, height1))
# load the pixels
pixels = i3.load()
# loop through all pixels
for i in range(width1):
for j in range(height1):
# xor the values
x = i1.getpixel((i,j))[0] ^ i2.getpixel((i,j))[0]
y = i1.getpixel((i,j))[1] ^ i2.getpixel((i,j))[1]
z = i1.getpixel((i,j))[2] ^ i2.getpixel((i,j))[2]
# if all white then convert to black
if (x,y,z) == (255,255,255):
(x,y,z) = (0,0,0)
# put the new pixels in place
i3.putpixel((i,j), (x,y,z))
# save the image
i3.save("test.png", "PNG")
```
This resulted in the following image:
