Encryption

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Definitions

Plain text - The data in human readable form.

Cipher - An encryption method or algorithm.

Key - The data used to encrypt or decrypt the plain text.

Cipher text - The encrypted data which can only be understood if decrypted.

Caesar Cipher

The creator was Julius Caesar. It is a substitution cipher which works by shifting letters by a number. The easiest way to look at a caesar cipher is to think of an inner and outer wheel, each wheel has the letters of the alphabet on its edge. When the letter A on both wheels are aligned the shift is 0 as in the image below:

The shift turns the outer wheel a specific number of spaces. The image below shows a shift of 7: