Learn About Caesar Ciphers to Help Crack This Week’s Easy Code
Caesar ciphers may sound complicated, but once you understand them, they’re simple and easy! The word “cipher” is another word for code, and people use Caesar ciphers to create and decode coded messages.
The Caesar cipher gets its name from Julius Caesar, a famous Roman general. Whenever he wanted to send secret messages to other military officers, he would use this type of cipher. That way, if the message fell into enemy hands or was intercepted, it wouldn’t betray any of his secrets or plans.
The cipher works like this. Say you have two sets of alphabets, like this:
The letters in the top set represent the letters in the coded message, and the letters in the bottom set are those in the decoded message. In other words, the letters on top are found in the scrambled message, and the letters on the bottom are part of the real unscrambled message.
This would mean that the letter A in the coded message would signify A in the decoded message. If I had put the letter B underneath the letter A, an A in the coded message would signify the letter B in the decoded message.
In order to create a Caesar cipher, all you have to do is shift the letters in the bottom set over any number of times. For example, if I shift the letters twice, the alphabet sets now look 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
Y Z A B C D E F G H I J K L M N O P Q R S T U V W X
Now, instead of A in the coded message signifying A in the decoded message, A in the coded message is really the letter Y, and the letter C in the coded message is now the letter A.
If I wanted to spell the word “CODE” with this new cipher, I would spell “EQFG.”
The way that Caesar’s generals knew how to decode his messages was that he would tell them how many times to shift the bottom alphabet set. However, in the easy code provided last week, I didn’t tell you this key piece of information. It’s up to you to figure out how many times I shifted the bottom set– shift it around until you find a cipher that works!