If you really want to add some sort of randomness, make it based on the user input. That way your randomness depends on what you send and won't be able to be su

If you really want to add some sort of randomness, make it based on the user input. That way your randomness depends on what you send and won't be able to be subtracted out. Or use constant time things (which is hard for the record!) and not have to deal with it.