---
# System prepended metadata

title: BITSCTF 2024

---

# BITSCTF 2024
## Forensics
### III) Convert Communications

> Player : TMQrX
> Description : rskbansal hacked into nasa mainframe and intercepted a radio signal from deep space along with a very SUS image. He tried using data representation but soon realised that he seems to be missing something...Help him figure out the secret!!!
> Hint : rskbansal asked Huffman for help, he suggested to maybe try messing around with histograms.
> 
![image](https://hackmd.io/_uploads/HyLXbUkn6.png)

First, I will analyze the WAV file first. Using deep sound, I obtained a secret.zip file. But this file requires a password to decompress. So I use sstv to extract the audio and get the password

![image](https://hackmd.io/_uploads/S1Rz781hp.png)

Unzip the file and I get two files: enc_data.pkl and tempo.pkl

![image](https://hackmd.io/_uploads/HkfLXUyh6.png)

Next I will process the image file. Based on the hint, I can know that it has used the huffman and histo-shift method. After some research, I came across a video that could solve this problem

https://www.youtube.com/watch?v=BuLFBSFdZBw

Build the script and process it with Histogram Shift then have a decoded binary file and use it to decode the Huffman algorithm and i got the flag : 

![image](https://hackmd.io/_uploads/BJu848yn6.png)

*FLAG : bitsctf{s73g4n06r4phy_15_n07_45_345y_45_17_533m5}*