Hopscotch Capture the Flag (HopscotchCTF)

Hello Hopscotchers!

As you know, Hopscotch has historically never had a shortage of competitions. Even now, we have numerous competitions occurring simultaneously. This has made it very hard for people’s competitions to gain traction and to actually happen. I hope that this competition will be different.
(Sorry for that terrible introduction, I couldn’t think of a better one)

I will be attempting to create and manage a type of competition called a “Capture the Flag”! CTFs are common computer competitions, and I thought it was about time that Hopscotch had one.

What is a CTF?

Great question, me! A CTF is a type of competition where participants attempt to find “flags” in puzzles. Here are a couple of examples of puzzles:

Finding flags in encrypted messages: participants may have to crack a cipher to find a flag. Example: 8 9- the flag here is ‘hi’

Finding flags in source code:
Participants may have to find the flag in a given program. The following program is written in C:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main(){
char * user_input = NULL;
char thing[6] = {104, 101, 108, 108, 111, 0};
size_t size = 0;
int equal;

printf("Input: ");
getline(&user_input, &size, stdin);

equal = strncmp(user_input, thing, 5);
if(0 == equal){
printf(“Aw, manners are always worth it. Hey to you too!\n”
“The flag is hopscotchCTF{< your input >}\n”);
The flag here is ‘hello’ (I’ll get to that formatting later)

Finding flags in binary files:
Participants may be given a binary file and will have to find the flag in it using some special binary editor (or using ‘strings’ or ‘hexdump’ in the Linux terminal for example)

These are just a couple of examples of puzzles. For obvious reasons, I can’t use all of them and will have to create a few that are unique to Hopscotch.

What types of puzzles will I find in this CTF?

This CTF will have similar puzzles to other CTFs, along with some other puzzles, and without some types of puzzles (I don’t think file-sharing is allowed, so no binary file analysis)

The most important type of puzzle will be cracking some given Hopscotch project and looking for a flag in it. That flag could be hidden in the code, or when played, or hidden across multiple projects, or even somewhere else on the Hopscotch app entirely!

That won’t mean that all of the puzzles will be Hopscotch-related. ALL PUZZLES WILL BE COMPUTERS-RELATED and some other types of puzzles that I intend to add include:

Trivia about computers, analyzing source code written in a variety of programming languages, cracking ciphers, and some others (that I haven’t thought about yet)


Flag format (Not important):

As you may have seen in my example about analyzing a C program, the flag was structured like so: ‘hopscotchCTF{< flag >}’ this was taken from picoCTF, and it won’t be necessarily implemented in this CTF.

CTF structure IMPORTANT:

The CTF will be split in two: the general CTF with all of the puzzles, and the Hopscotch-related CTF with only the hopscotch-related puzzles. This means there will be two winners, one that got the highest score throughout the entire CTF, and one who got the highest score with the hopscotch-related puzzles.

CTF point system IMPORTANT:

The point system is quite simple: every puzzle will have a certain amount of points associated with it. The harder the puzzle, the more points it is worth.

How do you submit your solution to a puzzle IMPORTANT:

I’m not sure right now. I’ll have to think about it, and if you have suggestions, feel free to give them! The issue with just submitting your solution on the forum is that other people can see it and take it. So I’m trying to figure out ways around that.

Where will the puzzles be posted?

Probably somewhere on this topic.

Information regarding the rules and other related stuffs

Can I team up with other people?

I’m not sure right now, but I’m leaning towards “no.”

Unless leaders want to give some prize, I don’t think there will be any. (This May change though)

I’m not sure when the CTF will start, but hopefully before August ends. The CTF itself will be quite short, a couple of days at most.


For this CTF to work, I need help. That’s why I need people to volunteer as “managers” to create puzzles and judge how hard they are. Hopefully we’ll have an unlisted topic for them.

If you want to participate in this CTF or be a manager, please fill out this poll:

  • I want to participate
  • I want to be a manger
  • I don’t want to partake

0 voters

I think that’s everything. If you have any questions, feel free to ask! Thanks!

People that asked to be tagged

@ExplodingDucks @ArcadeGrounds @FearlessPhoenix @Grizzlygoat1 @Petrichor @GweTV @SilverStar



So there will be one with coding languages and one with Hopscotch?


what’s a manger lol


One will be general and Hopscotch, one will just be Hopscotch.


Look at “jobs”
(Sorry everything’s so long)


I mean you made a typo lol
no need to sorry


Oh, poop. My bad.


This is sic.
I’d love to help out, but I’m not completely sure if I’ll be able to code some of the puzzles (my hs is still completely broken and I’m also pretty busy,). If that’s alright, then I’ll help out. If not, I’ll participate. This’ll be super fun either way :))


Thanks! It’d be amazing if you could help make puzzles, but it’ll also be awesome if you participate!


I could probably help design the puzzles, maybe just not code them. That alright or would you rather I participate? Either is cool with me


@Albus_Dumbledore I’m a bit confused, do you want to not participate or do you want to be a manager? Also, how did you vote twice?


I’m pretty busy these days so I’m not completely sure to be really active on this
is that okay?


I did? I don’t want to partake that’s all


If I don’t have enough people helping, it’d really help if you could helped design puzzles. But it’s all up to what you want to do!


Oh, okay. Thanks for clarifying!

That’s fine! You can join the CTF at any point, even during the competition! (Just not afterwards…)


Ok sic. I’ll stay as a participant for now, but if you don’t have enough helpers, I’ll switch over and help


Cool, thanks so much!


Yeah no prob :))


Will we be playing or making


If you are participating, you will be “playing”. It’s not really playing, it’s looking at the code and finding hidden flags.
If you are a manager, you make that code.

(There are also other puzzles that don’t involve code at all, like decrypting messages)