Codes & Other Spy Stuff

Ciphers and Codes—What’s the Difference?

A cipher is a way of hiding the meaning of a sentence by using a different symbol for each letter of the alphabet. When a spy translates a message into a cipher, she is enciphering the message. When another spy who has received that message figures out its meaning, he is deciphering the message. A code is a way of hiding the meaning of a sentence, phrase or word by using another sentence, phrase or word that has been agreed upon ahead of time. When a spy translates a message into code, he is encoding the message. When another spy who has received that message figures out its meaning, she is decoding the message.

Pig Latin

Pig Latin is a kind of code. Each word is substituted by another word. To encode a word into Pig Latin, take the first letter or letter sound (th, pl, wr, sl, str, cr, etc.) of that word and move it to the end of the word, and then add “ay.” (For vowels, use “way” instead of  “ay.”) So, “Here is the secret message” would be: “Ere-hay is-way e-thay ecret-say essage-may.” 

Substitution Cipher

Each letter in a substitution cipher is replaced by another symbol. In an alphabetical substitution cipher, each letter is replaced by another letter of the alphabet. Sometimes the substitution is simple. For instance: you can use the next letter in the alphabet as a replacement: “a” would become “b”;  “b” would become “c”; and so on (and “z” would become “a”). Sometimes the substitution is more complex. For instance: in the first word, use the next letter in the alphabet as a replacement, but in the second word, use the second letter in the alphabet after that letter, and in the third word, use the third letter in the alphabet after that letter, and so on. For instance, in the first word, “a” would be “b” and “b” would be “c” but in the second word, “a” would be “c” and “b” would be “d” and so on. Or you could use a completely random substitution. In that case, the person deciphering the message would need a key to the code, so he would know what those random substitute letters are. You could also use other symbols, in addition to letters of the alphabet. In that case, too, you would need a key to decipher the message. Unless both people have the key, it would be much more difficult to figure out what the message says!