What is the Difference Between a Code and a Cipher?

For many, the words code and cipher often induce the same thought.  However, there is a difference between the two words.  And even though code and cipher get interchanged a lot, even by myself, the actual definitions for the words establishes there should be a precise usage and understanding for each.

For instance, if a person came across the mysterious looking script, like the one shown below, more often than not, they would say, ‘Look! It’s a code.’

Ehvw ri oxfn zlwk doo wkdw brx vhhn! Dozdbv Wuhdvxuh wkh Dgyhqwxuh!

But is this a code? Or is it actually a cipher?

Let’s find out.

A Code is a method of replacing a word or phrase with another word, phrase, or symbol, for an entirely different meaning.  An example of such is that ‘Take out the Trash’ could be code for ‘Meet me in one hour.’  A codebook, listing words/phrases/etc and the codes for them, is essential for both the receiving and dispatching sides.

Another example of a code is where certain unlawful items, like Whiskey during the prohibition years, was replaced with common names, so people talking about the items didn’t alert others around of their illegal activity.   Someone could say, ‘When you get to Harry’s, pick me up some Spice’, when actually they wanted Whiskey.  The codeword of Spice for Whiskey was understood by only the two communicating. They were speaking in Code.

A Cipher, on the other hand, is an encryption system that is used to replace letters of a word. Only the person who is aware of the system used for encryption is able to understand the message.

So let’s look again at the mysterious script above.  The apparent gibberish is most likely a cipher.  To learn its message it must be deciphered by reversing the system that was used to encode it.

That is one of the key factors in determining if it is a code or cipher.  A code is often dispatched as something understandable to others, but it carries a secret message within those words for someone in the know.  A cipher, however, is often readily realized to be hiding a message.  It’s security comes from the system which hides it.

These are only the basic definitions for Code and Cipher.  Lots of times they can even be combined.  But I hope you can see the difference.

But since both codes and ciphers encrypt messages, it doesn’t ‘really’ matter whether a person says Code or Cipher.  There is an understanding a message is being hidden. The difference comes from ‘how’ that message is being concealed from the public eye.

 

Ehvw ri oxfn zlwk doo wkdw brx vhhn! Dozdbv Wuhdvxuh wkh Dgyhqwxuh!

PS- and if you’d like a hint for breaking the above code, or I mean cipher, see the following post: MW Codes, Ciphers, and Puzzle Series: The Caesar Shift