Posted on by and filed under CSAW Quals 2016.

With this challenge, they gave us an encrypted png. After a bit of trial and error I realized all I had to do was xor the first few bytes of the encrypted file with the standard header of a png. I just downloaded a sample file. Here is my get_key.py

Which gave me the key: Here is my decrypt.py Which gave me the image with the flag: View the original post here.