2Warm.md

2Warm

• Challenge information
• Solution
• References

Challenge information

Points: 50
Tags: picoCTF 2019, General Skills
Author: SANJAY C/DANNY TUNITIS
 
Description:
Can you convert the number 42 (base 10) to binary (base 2)?

Hints:
1. Submit your answer in our competition's flag format. For example, if your answer was '11111', 
   you would submit 'picoCTF{11111}' as the flag.

Challenge link: https://play.picoctf.org/practice/challenge/86

Solution

Convert in Python

We can use an interactive Python session to do the work for us with the bin function

┌──(kali㉿kali)-[/mnt/…/picoCTF/picoCTF_2019/General_Skills/2Warm]
└─$ python
Python 3.11.4 (main, Jun  7 2023, 10:13:09) [GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> print('picoCTF{' + bin(42)[2:] + '}')
picoCTF{101010}
>>> exit()

Convert with bc

Alternatively, we can use the tool bc to do the convertion. Install it with sudo apt install bc if it isn't installed already.

┌──(kali㉿kali)-[/mnt/…/picoCTF/picoCTF_2019/General_Skills/2Warm]
└─$ echo "obase=2; 42" | bc                                              
101010

In this case you need to construct the complete flag manually.

For additional information, please see the references below.

References

• Wikipedia - Binary number
• Python - Slicing Strings