intercept.md

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Intercept (2021)	HackTheBox Cyber Apocalypse CTF 2021	Rev	Writeup for Intercept (Rev) - HackTheBox Cyber Apocalypse CTF (2021) 💜	title description tableOfContents outline pagination visible true visible true visible true visible true visible true

Intercept

Video Walkthrough

Challenge Description

Intercept We managed to covertly spy on some of the elves' communications, as well as obtain partial code for their experimental encryption algorithm. Can you find where they're planning their next meeting?

Solution

{% code overflow="wrap" %}

from pwn import *

enc = unhex(b'5b2fedd4801914e7eb765119d4fe6223f1d1984638a9816b5419dac07b27eed9d35e09fdef65521ac5877a24eed19b0c0ae9f16d4c02cc86773bfaa8924a2ae9a12a2f1dd7923d39eea78d5909f9f57b2a16ddc87d33ada58f1208d4f737755283da1168a3e6cc075e8ce920774ef88d483fb1bb8a440884af7d69e2c5874b3bb3be695d4fd5a97b27e7d7d0572cf0bf665405dbfe4225e19b824813e4b96a4e178a95776fe1d8800b0bf7f0705719c0c37834a8f7a26f1febbe3d7119dad66427d5f58b4259eabc3f3626ded46621d3b0ca441afce552274bd6da1f2a')

dec = b''

for i, byte in enumerate(enc):
    dec += xor(chr((55 * i + 19) % 256), byte)

success(dec.decode())

{% endcode %}

Flag: HTB{pl41nt3xt_4sm?wh4t_n3xt_s0urc3_c0d3?}