WinterCTF 2025

I participated this ctf with a team of four, ddos andrew, and we got 3rd!

Challenge: Double Vision
Category: Forensics
Author: william
Flag: winterctf{jsxt_align_the_images}
Description: Line art yields easy readable secrets.

The chall provided two very simmilar images, pixels.png, and more_pixels.png

The two images were very simmilar, so my first thought was to compare them. I used this image comparer, which I previously used for another challenge in a different ctf.

The results look very promising! From what I can see, the text read “bnsyjwhyk{oxcy_fqnls_ymj_nrfljx}”. After running Dcode’s cipher identifier and using Caesar Cipher to shift it five positions, I got “winterctf{jsxt_align_the_images}”, which was the flag! My team ended up being the first team to complete this challenge, nice!

Thank you for reading this writeup!