If you ask any person, what is the difference between a cipher and a code, you will probably get the same answer I hear all the time. Both ciphers and code refer to the same thing. However, this is very much incorrect. Ciphers and codes refer to two completely different things.
In this article, I will be comparing codes vs ciphers so that you clearly see the actual difference between the two.
Read: What is cryptography.
A code is a mapping from something like a word, sentence, or a phrase into something else, usually a shorter group of symbols. For example, I could come up with a code where the word “kifanga” is written as 25.
Codes are used for saving on time when sending messages around the world. A code also requires a codebook that lists out all the mappings.
To put it simply, a code is a way of changing the message by replacing each word with another word or number that has a different meaning. For this reason, are hard to break, since even if an attacker manages to intercept the message, the code is completely unrelated to the original message.
On the other hand, ciphers are mechanical operations known as algorithms that are performed on individual small chunks of letters.
For example, the famous Caesar Cipher shifts every letter of the alphabet based on a key (usually from 1 to 25) thus mapping each letter in the alphabet to a different letter. For example, with a shift of 3, letter A is mapped to letter C, letter B to D, and so on.
Ciphers do not need a codebook but rather an algorithm that defines the set of steps to be followed to encode the information. Each algorithm also needs a key that is kept a secret and only shared between the communicating parties.
To put it simply, ciphers convert the message by a rule, known only to the sender and recipient which changes each individual letter or groups of letters. Ciphers are easier to use than codes since you only have to remember a specific algorithm to encrypt the message and not a whole dictionary of codewords.
The only problem with ciphers compared to codes is that if someone finds a message that has been encrypted using a cipher, the output is always going to be a random string of letters or symbols, and, and with that, the interceptor will know straight away there is a message hidden.
A general rule is that a good cryptographic system should be easy to use, both in encryption and decryption, but should remain secure against attempts to break it.
Here are the main differences between codes and ciphers
- Codes operate on semantics and meaning while as ciphers operate on syntax and codes.
- A code is stored as a mapping in a codebook while ciphers transform individual symbols according to an algorithm.
Now I want to hear from you.
What do you think is the best distinction between codes and ciphers?
Or maybe I missed an important aspect between these two terms.
Either way, let me know by leaving a comment below.