Secret Code 

A written code that only u know, or a few people know, that usually hides something.

I have to write a secret code to u so no 1 knows how to read it.

Secret Code by (h453 December 18, 2008

Secret code 

a code usually used between friends to say something that they don’t want others to hear

jhti hpfehompglge, vhni nmgafrgrvifa hygoju hagrce gdjohghgbi kphogo hpgodo.
this is an example of secret code

Secret code by Luv the alpaca May 21, 2020