Unimportant 60 points

Forensics - Solved (100 solves)

Written by KyleForkBomb

It's probably at least a bit important? Like maybe not the least significant, but still unimportant...

unimportant.png

source

A python script and a PNG picture

Look though the script, it just put the flag in the second bit of green channel of the unimportant.png

pixel = (pixel[0],                     Red
         pixel[1]&~0b10|(bits[i]<<1),  Green
         pixel[2],                     Blue
         pixel[3])                     Alpha

Wrote a python script to extract the flag:

from PIL import Image
from Crypto.Util.number import long_to_bytes
import re
img = Image.open('unimportant.png')
pixels = img.load()
w,h = img.size
def findFlag():
	flag = 0
	for i in range(w):
		for j in range(h):
			flag |= (pixels[i,j][1] & 0b10)>>1
			flag <<= 1
			if re.findall("tjctf{.*}",long_to_bytes(flag)):
				print(long_to_bytes(flag))
				return
findFlag()

Flag

tjctf{n0t_th3_le4st_si9n1fic4nt}