Julius Ceaser would use this cipher to encrypt messages to his generals in the Roman army. It is a simple substitution cipher that shifts the alphabet by a certain amount.

For example if you type 'abd' and shift by 1, the output will be bce. The alphabet is shifted by 1. A becomes B, B becomes C, and C becomes D.

Encrypted Text:

In order for this code to work I targeted values between 65 and 90 for uppercase letters and 97 and 122 for lowercase letters since these are the ASCII values for the alphabet.

ASCII table

You can think of ASCII values as a sort of library or framework the world has adopted so we can agree on what values mean what in terms of bits (binary digits).