Hamilton

Description

This challenge is from the internal BYU End-of-Semester CTF (Fall 2022).

https://www.youtube.com/watch?v=ua5bg06gLIQ

Writeup

Only two pieces of information are given for this challenge: a link to this YouTube video and a file with an assortment of numbers.

Part 1

The YouTube video is a clip of another video that’s become a meme, involving a grandma trying to name different Pokemon. Even if you don’t know the context behind the clip, the important thing to understand from it is that this challenge involves Pokemon.

Part 2

Looking at the provided file, you can see that it’s a series of numbers separated by periods. Since this is a cryptography challenge, it’s clear that these numbers must stand for something else, and from the video we know it must have something to do with Pokemon. Each of these numbers is below 1000, and if you are familiar with the Pokemon franchise, you might recognize that these numbers fit within the range of the National Pokedex numbers (a unique number given to each Pokemon). Therefore, by searching the web for something along the lines of “national pokedex”, you can find a site that provides a list of all Pokemon and their National Pokedex numbers (here’s what I used). By searching the page for the numbers in the file with Control+F (Command+F on Mac), I found that the first three numbers represented Bulbasaur, Yanma, and Unown. The first letters of each of these names spell out BYU, revealing that stringing together the first letter of each Pokemon’s name (corresponding to each number in the file) would return the flag.

FLAG: BYUCTF{THATSABEAUTIFULANIMALMYG}