Solution to Bornhack 2020 CTF challenge nc3

16/08/20 — capitol

tent_island

Name:

nc3

Category:

crypto

Points:

25

Writeup

This was the first challenge in the crypto category, just a couple of different encodings.

Challenge text:

base64:cmV2ZXJzZTo5UldZaTkxYno5RmR1TlhZMzlGZGhoR2Q3WkVWRGhrUTo0NmVzYWI=

We solved it with bash:

#!/bin/bash

cat nc3 | awk '{ print(substr($0, 8, length($0)))}'|base64 -d |\
    awk '{ print(substr($0, 9, length($0)))}'|rev|\
    awk '{ print(substr($0, 8, length($0)))}'|base64 -d
echo

Flag was BHCTF{that_wasnt_so_bad}.