Nice Encryption

Challenge Description

We managed to steal an encrypted message from the GDC. The problem is, it is encrypted with some unknown encryption. Help us to find the secret message.

Attached files

decrypt_me_plz

Solution

When opened in a text editor, the file seemed like gibberish. Looks like XOR to me!

To decode it, I used CyberChef to XOR brute force it: Screenshot 2021-06-24 at 11-05-35 XOR Brute Force - CyberChef

Lo and behold... the flag.

P.S. After submitting, the hint was revealed:

The first byte on the encrypted message is probably important…

I'm honestly not sure what to do with this information, since the key wasn't the first character. Strange.

Flag

CDDC21{Wh0_wrot3_th!s_Thin6?}