The Ol’ Switcheroo – Substitution Ciphers Old and New (for kids)

A Roman general paces in his tent after another long day of battle. A messenger from Rome has finally arrived with word about reinforcements, but the messenger himself knows nothing. In case he was waylaid, it was important for him to have no information—a wise precaution, it turns out, as this was the third messenger to set out with the message and the only one to arrive.

The general waits impatiently as his scribe decodes the message. Finally the scribe reads it aloud. “Help is on the way.” The general sighs in relief and dictates a reply to Caesar.

Secret codes and ciphers have been in use for thousands of years. There are many different kinds of codes and ciphers. A substitution cipher is a type of secret code that exchanges each letter in the alphabet for another letter or for a symbol. That way, if the message gets into the wrong hands, it won’t mean anything to the enemy.

Roman Emperor Julius Caesar, who lived from 100 to 44 B.C., was known for using a simple alphabetical substitution cipher to communicate with his generals during war.

The encryption key to Julius Caesar’s cipher is made by writing the alphabet twice. First, write out the whole alphabet and then repeat A-F after Z. Directly underneath the first alphabet, write another alphabet, but move it over by six spaces like this:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
U V W X Y Z A B C D E F G H I J K L M N O P Q R S T

 

To put a message into code, find each letter in the top row and substitute it with the letter directly beneath it. To decode a message, find the letter on the bottom row and substitute it with the letter directly above.

Now see if you can decode the general’s reply written in Caesar’s cipher.

QY MBUFF UNNUWE UN XUQH

 

That wasn’t too hard, was it? But Caesar’s cipher can be a pretty easy code for someone to break because the key keeps the alphabet in the same order and just shifts it over. It is easy to use to encode and decode messages, but unfortunately, it also makes the code easy to break. It’s a little too straightforward.

So let’s try something harder but still pretty simple for a busy, or embattled, general and his scribe to remember and encode. We’ll mix up the letters but in an organized way.

A name cipher begins with a name and then adds the letters of the alphabet that aren’t in the name in alphabetical order. When you choose a name for a name cipher, it’s easiest if it doesn’t have any letters that repeat. A long name is good, too, unless it has a lot of repeats. For example, if you choose the name Amanda, the seven letter name only really counts as four letters for the cipher key because three of the seven letters are ‘a.’

For this example let’s start with James since it has no repeating letters.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
J A M E S B C D F G H I K L N O P Q R T U V W X Y Z

 

If you look at the end of the alphabet in the key, you’ll see that a lot of the letters stay the same. This might be a flaw in the code, but it might just turn out okay. We’ll see. Before you start decoding, take a good look at the message. Are there any words that you think you can guess without the key?

You can try to solve the whole message without the key, or use the cipher key above to decode the message below.

QNRSR JQS QSE

VFNISTR JQS AIUS

YNU DJVS RNIVSE TDFR MNES WSII

CNNE BNQ YNU

Did you notice that you could use the length of the words to help you decode them even without the key? In this message the word “you” was spelled YNU, so it was pretty easy to guess if you were trying to break the code.

One way to make breaking the code harder is to take the spaces out of the encoded message, so the words all run together. Code makers often transmit messages in groups of five letters with a space between. This makes it harder to guess the words.

This last substitution cipher uses symbols instead of letters, and it’s broken up into blocks of five letters. Can you solve it?

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
~ ` ! $ # % & ^ * ( ) _ + = ? / { ] [ } | \ : ;

 

;-}~{  #~$#!  -$*=&  !^~+?  *-==-  \*[*]  [*+#[  -+~)#  ;-}{-  \=]}`  ][*[}  [*-=!  *?^#{

 

Now you can use what you’ve learned about substitution ciphers to make your own. Will you make it with letters or symbols? Make two copies of the key and start exchanging secret messages with a friend!

“Star Wars” on the Reservation (for kids)

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Photo by Colin Bedson used under a creative commons license.

A kids’ article, part of this week’s repost series.

There’s a new version of Star Wars in select theaters, and it’s on a mission to keep the Navajo language alive.

The Navajo are a Native American people who live in the southwest United States. Recently, the elders of the Navajo people became concerned because thousands of Navajo children and young adults are learning English as their primary language instead of learning the Navajo language, Diné (DEE- nay). Many Navajo children speak and understand little Diné. The elders decided to act to keep Diné alive.

Manuelito Wheeler and the elders of the Navajo people picked George Lucas’ 1977 movie Star Wars Episode IV: A New Hope to help teach the ancient language of the Navajo people. They knew that both adults and children would enjoy watching Star Wars over and over, and they’d have to watch a lot to learn Diné.

Diné uses both words and tonal change to convey meaning. It is extremely hard to learn if you haven’t grown up hearing and speaking it.

What is tonal change?

English doesn’t have many examples of tonal change, but here’s one. Think about how you ask a question in English. At the end of the question your voice goes up. That tells your listener you are asking a question instead of making a statement.  (In a statement, your tone goes down at the end.) Unlike English, in Diné, there are tonal changes throughout the sentences that have meaning, too.

The elders figured that if the English-language voices in the movie could be replaced by voices in Diné using a process called dubbing both children and adults could enjoy watching the movie, and kids who didn’t speak Diné  would begin to understand the words and tones. Wheeler contacted the makers of the film to see if they would be willing to help, and they were.

Once it started, the project was completed very quickly. A team of five translators worked together on the script, and the whole translation was finished in about thirty-six hours. They had to work hard, though. A lot of the words in the original film simply don’t exist in Navajo, so the translators substituted other words.

Translator Jennifer Wheeler gave one example of a word important to the movie that couldn’t be easily replaced in Diné. “Droid” is a technological word, and there’s no word for it in Diné.  So the translation for “droid” might be “the short metal thing that’s alive.” That makes talking about R2-D2 and C3P0 a mouthful!

Dubbing is the process of putting new voice sounds in place of the original voices in the movie. In dubbed movies the movements of the actor’s lips don’t match the words viewers hear. The original words also limit the amount of time you have to say things. The Navajo translators had to make some changes so that the Diné words matched the movements of the actors’ lips a little better.

The dubbing process was easiest for the battle scenes where there’s a lot of action. When the action is intense, viewers are not focused on the actors’ lips the way they are in a quieter scene. Darth Vader was also easy to dub because his mask hides his lips.

Manuelito Wheeler, director of the Navajo Nation Museum, had the great idea to use Star Wars to help preserve Diné. And it seems to be working. Young people at the first viewing of the film told James Junes, the Navajo actor who dubbed Han Solo’s part, that they planned to speak more Diné now that they had watched the movie.

What movie would you choose to help preserve an ancient language?