Tags: morse audacity frequency-analysis stego
Rating:
The challenge text reads:
A raging Real Wild Child!
Flag is the STRING you end up with after solving challenge, case insensitive.
With an attached ```rage.wav``` file.
When playing the audio we hear a distinct rythmic beeping in the background.
A quick frequency analysis with [audacity](https://en.wikipedia.org/wiki/Audacity_(audio_editor)) shows us, that the beeping noise centers around the 500Hz range on the Frequency spectrum:

After applying a frequency filter, which blocks everything except the 500Hz signals the morse code becomes the dominant element in the sound file.

We export the 'clean' sound file as ```reage_morse.wav```.
Trying to decode the morse code by hand was too slow and tedious and was errorprone due to lack of training:
```
Morse code:
R: .-.
A: .-
G: --.
E: .
R: .-.
G: --.
T: -
O: ---
W: .--
E: .
I: ..
R: .-.
D: -..
.-..
..
-...
..
-..
---
```
But there is an app for that:
https://morsecode.world/international/decoder/audio-decoder-adaptive.html

With a bit of manual tweaking the clear decoded message is displayed and can be entered as a flag.