The Khatrimaza-org-mkv -

Challenge category: Forensics / Steganography Difficulty: Medium‑Hard Points: 500 (on a typical 500‑point line) 1. Overview The challenge provides a single file: khatrimaza-org.mkv . The file is a regular‑looking Matroska video container (MKV) – the kind you would normally see on the infamous “Khatrimaza” piracy site.

$ mediainfo khatrimaza-org.mkv General Complete name : khatrimaza-org.mkv Format : Matroska File size : 84.3 MiB Duration : 00:03:45.000 Overall bit rate : 2 028 kb/s The Khatrimaza-org-mkv

def xor(data, key): return bytes(b ^ k for b, k in zip(data, itertools.cycle(key))) $ mediainfo khatrimaza-org

$ binwalk hidden.bin

Audio ID : 2 Format : AAC Channel(s) : 2 channels Sampling rate : 44.1 kHz Bit rate : 128 kb/s k in zip(data

#!/usr/bin/env python3 import sys

inp, key, outp = sys.argv[1], sys.argv[2].encode(), sys.argv[3] data = open(inp, 'rb').read() open(outp, 'wb').write(xor(data, key)) print(f'Decrypted inp → outp using key "key.decode()"') Run: