What
is the difference between a CODE and a CIPHER?
A CODE
is based on COMPLETE WORDS or phrases. It is like a dictionary
where all the words are replaced by codewords or numbers. You
need a CODEBOOK to send or read a code.
A CIPHER
uses SINGLE LETTERS. These are either jumbled up or replaced by
other letters, numbers or symbols. Complicated ciphers involve
both. Ciphers can be memorised so a codebook may not be needed.
Here we sometimes use the more familiar word CODE to mean either
a code or a cipher.
