This one’s a short but sweet writeup for future reference: this 100-point (?) challenge came in the form of a FLAC audio file. We threw around some ideas for a bit, and then someone hit upon the realization that we could simply open the file in Audacity and take a look around. Sure enough, there was a noticeable spike:
A little bit of zooming in later:
After trying to convert this into some manner of binary string, it dawned upon us that this was frequency-modulated morse code. 5-minutes later, and we had the flag: “morse_is_fun”.
Well played, TUCTF, well played.