Cyber Explorers Escape Room: Cryptography
By: Citlalin Galvan
Tags: Quick Reads, Cybersecurity, Cryptography, Escape Room, Security

A quick look into cryptography, the history, and the process of encrypting and decrypting codes. Read before or after trying out our escape room!

Sending secret notes to your friends can make you feel like a spy on an important mission. What happens when the enemy spy gets a hold of your secret notes? They can ruin all your plans! But what if I told you, you could send a message that only your partner understands and even if the enemy tries to read it, they will be confused. Let me introduce to you Cryptography, the art of encrypting or decrypting secret codes with a shared key.

Cryptography and secret messages have been used throughout history by kingdoms and militaries. In 449 BC Histiaeus shaved a loyal blind slave’s head and tattooed a plan for a revolt to Aristagoras. He then had the slave grow out his hair to cover the message and instructed the slave that only Aristagoras could shave him which would miraculously give him his sight back. Unfortunately, he did not get his sight back, but the message got to Aristagoras safely without anyone knowing about the plan, and the revolt began! In England, Queen Elizabeth sent a type of cryptography called Steganography disguised as a greetings letter to help Sir John Trevanion escape from execution. The hidden message is Panel at the end of chapel slides when you use the third letter after any punctuation. Check it out below.

“Worthie Sir John:­ Hope, that is ye beste comfort of ye afflicted, cannot much, I fear me, help you now. That I would saye to you, is this only: if ever I may be able to requite that I do owe you, stand not upon asking me. ’Tis not much that I can do: but what I can do, bee ye verie sure I wille. I knowe that, if dethe comes, if ordinary men fear it, it frights not you, accounting it for a high honor, to have such a rewarde of your loyalty. Pray yet that you may be spared this soe bitter, cup. I fear not that you will grudge any sufferings; only if bie submission you can turn them away, ’tis the part of a wise man. Tell me, an if you can, to do for you anythinge that you wolde have done. The general goes back on Wednesday. Restinge your servant to command. ­ R.T.”

Cryptography Methods

Cryptography is the process of making easy to read plain text into intelligible, difficult to understand to an outside source. The are plenty of methods to encode your messages, some common ones are:

Transposition Cipher — a method of encrypting where the positions held by units of the plain text are shifted according to a regular system so that the ciphertext creates a transformation of the plaintext.

Steganography — the practice of hiding a message, which can be an image, file, or video inside a different file, message, image, or video. (Example: letter directed to Sir John Trevanion)

Substitution — a method of encrypting where the parts of the plain text are replaced with ciphertext, according to a fixed system or formula. The parts that are substituted can be single letters, pairs of letters, and so forth. Two common substitution ciphers:

Caesar Cypher

Freemason Cypher

Computer Assisted Cryptography — Developed tool-assisted methodologies for helping design, analyze, and implement cryptography into computer languages.

Binary Numbers

XOR

Hexadecimal Numbers

XOR

C

AES ECB

Encrypt vs Decrypt

- The Process of Encrypting and Decrypting -

When you encrypt a message, you are converting the message into a code to prevent unauthorized access. We encrypt data when we send it through the internet. This is why when you try to open a website’s source code, you might understand the format, but not the words much less the overall program. When someone wants to read the secure message, they decrypt the message by solving the code. To encrypt a message, you use a formula called a key. This key has to stay constant throughout the whole message so when it is time to decrypt it will give an accurate result. The key can be as complicated as you would like it to be. The more complex the key is, the more difficult it is to brute force solve it and get unauthorized access.

Caesar Cipher Practice.

Now that you have an understanding of cryptography, let's try a substitution cipher. The Caesar Cipher is a method where each letter in the alphabet is replaced by a different letter depending on the shift key. This method is named after Julius Caesar, who used it for his secret messages.

Let's encrypt “Cryptography is fun!” with the key being shift=3.

As you can see, A becomes encrypted to D, B to E, C to F and so forth. “Cryptography is fun!” becomes “Fubswrjudskb lv ixq!”

When using a Caesar Cipher Wheel, you use the outer alphabet as plaintext and the inside alphabet as the encrypted text. When you encrypt text, you will turn the inside alphabet clockwise, but when you decrypt, you turn the inner alphabet counter-clockwise.

Resources

Check out these pages to get more information!