ICS3UC Challenges

In the spirit of the CTF challenges around the Internet, I will post a few challenges on this page. Any challenges that students complete successfully are considered extra credit. These challenges are optional. Several can be found on picoCTF as well.

The Rules (click to expand)

  • Challenges are to be completed individually. Collaboration is always recommended in terms of assisting and generating ideas for projects, creating solutions to the world's problems, and in most things we do in life... these challenges are not that. You are to work individually.

  • Do not share solutions. Be proud of figuring out the correct solution and move on. Sharing solutions could exempt you from future extra-credit.

  • No bragging. Part of keeping solutions secret and safe is learning to be humble. Feel free to express that you successfully completed a challenge and then move on.

  • Telling someone "that one's easy" could exempt you from future extra-credit. Nobody wants to hear "that's easy" when they find something difficult. Instead, ask them what about it is difficult or how you might be able to help without giving away the answer.

  • In order to submit the solution to a challenge, you are to email your teacher directly.

      • The subject line of your email must be in the format <title>: solution
        For example, if the challenge was called "Fancy Feast", your subject line should read "
        Fancy Feast: solution"

  • Solutions are always secret text (the flag). You are to submit the flag in the following format as the body of your email: CTF{the flag}
    For example, if the flag was "
    is delicious" your email would have the subject "Fancy Feast: solution" and the body would read "CTF{is delicious}"
    Other text in your email is fine (saying hello, commenting on the difficulty of the challenge, etc). Please sign your email as discussed in class.

C.00 - "Inspector Gadget"

Can you find the flag? Click here to see if you can!

C.01 - "The Numbers"

What do the numbers mean? Click here for the file

C.02 - "The Garden"

This garden contains more than meets the eye. Click here for the file

C.03 - "Too Easy"

Cryptography can be easy, do you know what ROT13 is? PGS{abg_gbb_onq_bs_n_ceboyrz}

C.04 - "Caesar"

There are SO many types of cryptography, some just require a bit of brute force.

Some caesar dressing was applied to the key. Can you figure it out? CTF{gvswwcvsehwsvjpettcfmvh}

C.05 - "Huh?"

-- ----- .-. ... ...-- -.-. ----- -.. ...-- .---- ... ..-. ..- -. ..... - ----- .--.

C.06 - "2^6"

In the tech industry, standards are established to facilitate information interchanges among computers. How does a Mac talk to a Windows device? Unfortunately, I've made communication a little bit more difficult. Can you figure this one out?

43 54 46 7b 63 6f 6d 70 75 74 69 6e 67 5f 70 6c 75 73 5f 6d 61 74 68 5f 65 71 75 61 6c 73 5f 73 63 69 65 6e 63 65 7d

C.07 - "Time Machine"

Let's go back in time to December 31st, 1996. The flag for this challenge is the email address listed on nasa.gov on that date (Dec. 31st, 1996). The format for submission would be CTF{email} where "email" is the email address posted on that date.

C.08 - "QR"

Did you know that the QR in "QR Code" stands for Quick Response?

Here's one.

Learn Linux

For now I do not have any more challenges for you to complete. Soon I will be giving you a website on which to practice your skillz but first you must learn, young padawans!

There are so many tools in behind your operating system (yes, even on a Chromebook). I think it's important that you start to learn some of the more complicated tools out there. For that, you should start learning Unix commands (well, Linux but that's a lesson for another day).



Free online virtual machines with Linux:


Setup Linux on your Chromebook (newer models):


Setup Linux on your Windows 10/11 computer:


Tips & Tricks

  • Never be afraid to inspect a file or website in various ways!

  • Highly recommend the tools available online like CyberChef and Boxentriq

  • Files are written to the disk in binary and viewable in various forms. One very popular form is Hexadecimal. Opening a file in that format can reveal some interesting details.