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Challenge Description

As the challenge description suggests, we must be equipped with basic knowledge of different data encodings in order to solve this challenge.

However, there are many types of numerical encodings or data encodings used to represent data in different formats. We will need to know which are used for this challenge.

To do this, we run the command given in the challenge:

nc jupiter.challenges.picoctf.org 15130

What do we need to do?

How does the challenge work?

We are first tasked to convert a binary (base-2) representation of a word to the original word. There is a time limit of 45 seconds for us to submit to correct answer.

If the answer is correct, we will then be given an octal (base-8) representation of another word. Our task is basically the same; we have to decode the octal representation and submit the correct word.

The final stage will require us to decode the base64 representation of a word. After which, the answer submitted is correct, we will be awarded with the flag.

Conversion

I created a couple of python scripts to aid me in the conversion:

Python scripts used for conversions

Stage 1: Binary Conversion

# Binary conversion
 
word = ""
binary = input("Enter binary representation: ")
 
for octet in binary.split():
   char = chr(int(octet,2))
   word += char
 
print(f"The word is '{word}'.")

Stage 2: Octal Conversion

# Octal conversion
 
word = ""
octal = input("Enter octal representation: ")
 
for num in octal.split():
   char = chr(int(num,8))
   word += char
 
print(f"The word is '{word}'.")

Stage 3: Hex Conversion

# Hex conversion
 
word = ""
hex = input("Enter hex representation: ")
 
for i in range(0,len(hex),2):
   hex_char = hex[i] + hex[i+1]
   char = chr(int(hex_char,16))
   word += char
 
print(f"The word is '{word}'.")

Solving the challenge

I proceeded to run the above command to connect to the server once again, and used the scripts shown above to convert the values accordingly. I used a separate terminal to do the conversions.

After submitting the right input, I was awarded with the flag for this challenge.

Flag

picoCTF{learning_about_converting_values_02167de8}