Lock CPU

Hi

I would like to know if there is a way to lock the module so that it can only accept AT commands from a certain application. For instance, a password that has to be sent when the serial connection is made?

Thank you in advance

sure, you can write your own wrapper around the normal AT-commands…
however, what use would it be?
a simple serial port sniffer application would reveal your ‘password’ or wrapper instantly?

So you’d also have to encrypt it…