Too many Layers

gkkab://bgrsktsq.vk/NWPVF

Hey there, fellow code-cracker! Today, my brother, who’s fond of ciphers and steganography, sent me a mysterious link to a file filled with secrets! 🕵️‍♂️🗝️ He hinted that I need to use an algorithm but was delierious from all the attempts. I couldn't tell what code to use but it sounded like cAFFINE and the magical code word is “today.”

Can you help me unravel this enigma and uncover the elusive flag hidden within? Let’s put our detective hats on and decrypt this together! 🔍✨

We are given a link that seems to be encrypted. Based on the clue, the algorithm would most likely be "Affine cipher" and the key "today" which would be "9/21", the date of the CTF. I used dcode.fr's tool for this.

Now we can visil the link at https://shorturl.at/CDIAE and we get an image.

I tried to do many steganoghraphy techniques on this image, such as exiftool, binwalk, basic lsb, etc. Then, as any desparate steganographer would do, I finally ran zsteg -a on the image to check for all bit plane possibilites and got this:

I assumed that the phrase is likely to be a question for the flag. The answer to the question is Alan Turing, who created a machine to crack the Enigma and helped the Allies won the war.

Flag: flag{Alan Turing}