I think in order to explain the difference between the different types of ciphers, you
should really consider where ciphers came from. I am not trying to pull a Sheldon
Cooper on everyone, but ciphers were used WAY back in history. For example, a
cipher that is still used to date is the Caesar Cipher, which was developed by Julius
Caesar. I always find it interesting when we continue to use designs that were
developed a long time ago.
The character ciphers are what it sounds like. We take a single character and
replace it with another character, known as ciphertext. Character ciphers are not
very hard to crack though. I would honestly not use this for anything, besides writing
