README.md

picoCTF 2022: basic-mod1

Author: Will Hong

Description

We found this weird message being passed around on the servers, we think we have a working decrpytion scheme.

Download the message here.

Take each number mod 37 and map it to the following character set: 0-25 is the alphabet (uppercase), 26-35 are the decimal digits, and 36 is an underscore.

Wrap your decrypted message in the picoCTF flag format (i.e. picoCTF{decrypted_message})

Hints

Hint 1

Do you know what mod 37 means?

Hint 2

mod 37 means modulo 37. It gives the remainder of a number after being divided by 37.

Summary

Performing the modulo 37 operation on every number gives a new set of numbers. Syntax in most common languages:

number % 37

You can either substitute the new numbers by hand or write a script for it. Example is given in the solve subfolder.

Flag

Show flag

picoCTF{}