picoCTF - The Numbers

• URL: https://play.picoctf.org/practice/challenge/68
• Title: RED
• Tags: Easy, Cryptography, picoCTF 2019,
• Author: Danny
• Started: 20 July 2025
• Solved: 20 July 2025
• Description: The numbers… what do they mean? numbers.png

Opening numbers.png, it showed this

I noticed the curly brackets and the 4 starting numbers: 16, 9, 3, 15. If you align it with alphabet order. I could just use pen and paper or even code about it but in this case I used CyberChef, the algorithm is called A1Z16

The flag is picoCTF{thenumbersmason}