Log /Id- in to a Blynk App

Hello, I'm new here.
I have the following problem:
I implemented a garage door control with Blynk and ESP32.
The app only has one push button with which I can open / close / stop the garage door.
Everything works fine.

Now the problem:
We have several mobiles in the house, and to get the app on them,
I have to publish the app.
Once the app is published, anyone can download it and
then can control my garage door with it.
Question: How can I solve it that, whenever you start the app,
you have to authenticate yourself first. As I said, only when you start the app.
I don't want to have to enter a PIN code before each time I push the button.
Its too cumbersome and annoying.

is there something unique on your phone (i.e. name, phone number) that can be sent and the esp32 code only responds when a command is prefixed by it?