For those of you who want to give love letters without getting caught_^
Caesar Cipher was invented by Julius Caesar around 58 BC. Caesar cipher is a type of substitution cipher that forms a cipher by exchanging characters in plaintext into exactly one character in chipertext. The way to use it is also quite easy, namely exchanging one character replaced with a character that is in a number of digits to the right or left, depending on the direction of the shift.