---
title: AperiCTF 2019 - [Crypto] Simple Basique (50 points)
author: Maltemo
tags: CTF, AperiCTF, Crypto, URLEncode
---

AperiCTF 2019 - [Crypto] Simple Basique (50 points)
===
Written by [Maltemo](https://twitter.com/Maltemo), member of team [SinHack](https://sinhack.blog/)

[TOC]
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## Statement of the challenge

### Description
Un apprenti cryptologue souhaite communiquer avec vous:
%51%56%42%53%53%33%74%43%4e%48%4d%78%63%58%55%7a%58%31%4d%78%62%58%42%73%5a%53%46%39%43%67%3d%3d

## Analysis

This strings look like a URL encoded string, so let's translate it to readable characters with [this site](https://www.urldecoder.org/):

QVBSS3tCNHMxcXUzX1MxbXBsZSF9Cg==

This string looks like a base64 encoded string.

Let's convert it to string from the console :

echo -n "QVBSS3tCNHMxcXUzX1MxbXBsZSF9Cg=="|base64 -d

:::info
**Little tips** :
* When you see a string composed of `%xx` with x being hexadecimal characters think about URL Encoding.

* Also, strings ending by `=` or `==` will often be base64 encoding.
:::

## Flag

And we got the flag : **APRK{B4s1qu3_S1mple!}**
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