Define \[\textit{plaintext}\]\[\textit{ciphertext}\]

Method of cryptography Caesar employed?

Define \[\textit{simple substitution cipher}\]

Convenient way to describe the encryption and decryption function of a simple substitution cipher

How many simple substitution ciphers exist for the alphabet?

Define \[\textit{key}\] for a simple substitution cipher

Define \[\texit{cryptanalysis}\]

Define \[\textit{symmetric ciphers}\]