Introduction for Parents and Educators:

There is much discussion around cyber security skills and talent shortages approaching. However, just like the learn2code effort, teaching STEM to kids is not exactly an easy task. Many concepts and hands-on skills are difficult for adults, let alone kids. Cyber and information security has a vast array of knowledge you must master. Cryptography and Signaling is among these skills. Why teach children these skills as opposed to deploying a firewall first? It’s because these skills are used everyday and we see it in movies. This article will briefly cover the use of ciphers for encrypting plain text and decryption as well as the mechanisms (signaling) on delivering plain or cipher encoded messages. For parents that want to provide this information in an hands-on approach using my PowerShell script, please follow along and refer to my github for a copy of the material. The language used in this article have also been simplified so that children can also read along. The recommended grade level to teach this lesson to is 4th grade or higher. Are you ready to take your child’s STEM skills to the next level? Follow the links as well for complementary reading. Read on!

Introduction for Cyber Security / Technical Professionals:

Some of these sections are meant for parents to have meaningful activities teaching their kids signaling/ciphers. So there’s theory and the use of PowerShell through a 2D array ingestion of for the word search. You can skip over some of the theory and go straight to my Github and review the comments for more usage and ideas. You can go directly to the signaling sections for ideas on how to communicate in an obfuscated manner that would be difficult for SIGINT analysis while combining linguistic crypto.

What are Ciphers and why use them?

Ciphers are functions either through a form of math formulas or some other form of methods that can be repeated through steps. Ciphers are a small part of the world of cryptography where the primary goal is to hide messages or communications from people you don’t want to know what you’re saying. It also means you only want your messages to only be understood by your intended friend. Ciphers also reveal or unlock hidden messages through a key, something only you and your friend know. Someone without he key cannot unlock the hidden message. As illustrated below, you take the method or steps you want to use to hide or encrypt the message and combine it with as secret (your key). Now the message becomes unreadable until your friend uses that same key to unlock or decrypt that the message:

To further explain for example, you wish to send your friend a message saying: “Are you online?” but you don’t want your other friends to know. You use a cipher and a secret key to encrypt your message that prevents it from view; equivalent to a lock box. Your other friends can’t open the lock box of containing the real message because they don’t have the key. The friend you sent the message to, will have your same key and then unlock the box to reveal the secret message you have sent. This is known symmetric encryption because you both use the same key to encrypt and decrypt the message.

Parents: Ask your child the difference between an encrypted message and a decrypted message?

Tip: Re-enforce the concept of the message in a lock box concept.

What is signaling and how are signals used?

Signals are any representation that “means” something to you or someone. For instance, speaking to someone; the set of noises and gestures you may make with face and hands all form one or more signals to your friend you’re speaking to. When you write a message on a piece of paper and hand it to your friend, you are sending a signal, and your friend is receiving a signal. The signal is the piece of paper that transfers your message to your friend. You could send a different signal for the next message you want to send through by saying your message to your friend. If you write a letter to your friend, that’s one signal. If you want to walk up to your friend and tell your friend something else or the same thing, that’s another signal. Two distinct signals.

Parents: Ask your child to give you a 3rd example of a signal

A Solution: You can also signal “YES” by nodding your head, or signal “NO” by shaking your head.

Putting it together: Using Word Search Puzzles for Crypto and Communicating Signals

Let’s get hands-on with using ciphers and signals to communicate those hidden messages to our friend(s). Do you remember how a word-search puzzle works? You find words in a scrambled set of letters to reveal the messages someone wants you to solve. The following illustration is an example of a 15x15 square of letters with the followings that I may want to send to my friends! But before you go “solving” the word search puzzle; I want to communicate the phrase “change security” to my friend. But how do I hide it from anyone else seeing it but my friend?

OK I want to send the message “change security” to my friend without it easily been seen by other friends? Well we have to first use a cipher, as series of steps or math that will take “change security” and turn it into something not readable by anyone else but my friend.

Parents: Ask your child what components are needed to encrypt the message “change security” when I send it to my friend?

Solution: I will need the following components: my plaintext message = “change security”, the cipher (steps to encrypt the message), and the secret key (to unlock the lockbox) for message decryption.

The Encryption Cipher of the Word Search Puzzle

Great! We have our components identified of what to use to send our message but how do we convert a word search puzzle into a cipher? We don’t. The word search puzzle is an array of 2-dimensions (2D) is actually is the key you’re going to give to your friend so they also have a copy to decode the message. We’re also not going to “solve” the word search puzzle by circling the words. We’re going to use what’s called substitution and transposition as our cipher. Substitution is when you replace a character (letter) or word with something else in its place. A transposition is when you “shift” or “move” a character or word based on a specific offset interval.

A combined example of substitution and transposition cipher method is when you replace the letter “A” with the number “0” or the letter “B” with the number “1” and “C” with the number “2”. We start with 0 because it’s the offset, or position, of the English alphabet letter (26 letters total, but we start from position 0 that ends at 25). The substitution happens because A is no longer “A”, it’s represented by a number. The transposition happens because we’re basing “A” based on its offset position of “0” because it’s the start of the alphabet. Remember an offset means a start from a position, not the “next step” like we do with counting “1,2,3…etc” This is also known as a variant of the Caesar cipher; our example is specifically (ROT-0) which means rotation of 0. The original Caesar cipher was ROT-13.

How do we apply substitution and transposition as a cipher to the word search puzzle?

If we look at the word search puzzle as a 15x15 square, we can think of it as quadrant (Quadrant 4 specifically) from a math plane and assign each letter within as coordinate pairs. So the first letter in our puzzle, which appears to be “F” we can think of it as the pair, x=0, y=0 (0,0) because it starts at the first position (0 offset) for both the row and the column in the square. This is illustrated below:

Now what would we do if we wanted to encrypt the word “fun” using our word search as the _key _and our coordinate method (substitution and transposition) as our cipher? Let’s start off with the anywhere letter “F” appears.

Parents: Be sure to remind your child that it isn’t important the “solve” the cross word puzzle with specific words, we’re just using it as a shared secret key. If you were to have the child solve the puzzle by just finding words out of it, it defeats the purpose because it provides easy-plaintext readable messages that isn’t obfuscated or encoded. Tip: If your child is wanting to focus on solving the word search, let them solve it. Then when they ask if it’s encrypted or insist that it’s encrypted; you refer back to the prior section on symmetric encryption and explain how another friend or parent could easily read their circled words on the page. Also remind them on the point of encryption (using ciphers) was meant for.

So we know one position of the letter “F” is (0,0) at the top left corner. Let’s find and determine a position for the letter “U” and “N”. Pick anywhere you wish!

#cryptography #cybersecurity #education #encryption #learning #deep learning