Encryption and Codes: What You Should Know

Learn about encryption and how you use it every day.

Have you ever seen an old spy movie and wondered how they got information passed around before computers and cellphones and the internet? It took a lot of planning and commitment! Those messages had to be coded if the spy was captured. Early encryption was simple, but as time passed, people caught on and learned the codes. Now encryption is a part of everyday life—codes are mixed together with computer algorithms to make them almost impossible to decipher. Keep reading if you want to learn more about codes and code-breaking!kid

The early days

One of the earliest ways to pass a coded message between people was to write a normal letter. But that letter would contain a secret message. Sometimes the words on the edge might say something when read together or every few letters could spell out a code. Another way was to wrap a strip of cloth or paper around an object and then write your message in a line going down, then fill in the blank spots. The person receiving the message would know what you used to encrypt the code and would decipher it by wrapping it around a similar object.

The problem with these early codes is that they could be deciphered with a little hard work. You could put together different patterns until they started to make sense. Even if the words themselves were a code, you at least learned what your enemies were saying to each other.


Not like the kind you use to open a door, but ones used to base your code on. During the Renaissance era, Leon Battista Alberti invented code wheels. He was a Renaissance Man in the truest sense of the word. He was an architect, a poet, and a cryptographer. A cryptographer is someone who designs a code and helps break codes made by other people. With his code wheels, you could set one letter to represent a different letter. The more rings, the more complicated the code could be. But unless you knew the key, you would have a hard time putting the code together.


By World War II, code encryption and deciphering were up to computers. Not the kind we think of today—these were mechanical computers. Coded messages were being sent over radios, so they had to be very hard to crack since everyone could listen to them. The Germans used the Enigma machine to write their codes. The machine had rotors that were set to a specific key. The machine would spit out a different letter every time you typed it so there was no obvious pattern. The English, led by Alan Turing, built a computer that could crack the Enigma. Their efforts saved countless lives as the Allies were able to maneuver around Germans and outsmart them.

No code

Another code used during WWII wasn’t a code at all. While the United States was fighting the Japanese in the Pacific, the U.S. codes kept getting broken by the Japanese. The solution was to use the Navajo language, spoken by the Navajo Nation people. It was a rare language that people outside the tribe didn’t know it, but codes could be sent and deciphered almost instantly by native Navajo speakers in America! These brave Navajo Code Talkers fought in every major battle in the Pacific, and their code was never broken.


Codes and encryption are used all the time today. From the messages you send on your phone to your parent’s credit card. A cell phone is basically a very fancy two-way radio. But the signal from the phone is encrypted so only someone with the right key can decode it. That means it’s impossible for someone other than you or the person you’re calling to listen in. The same for credit cards. When someone buys something with a card, there are multiple keys involved that help encrypt the numbers so the company knows the card is real.


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