Is it possible to hide a variable so that people who look in the "Variables" tab of the forms instance can't see what the value was? For instance: an IT group fills in a form with a secret code for a user, which nobody else in the organization should know. The process uses the variable to send an email to the user, but if someone checks that process instance later, they should not be able to see that code in the variables anywhere.
Hope that makes sense.