i'm working on a project and need your ideas, advices.

First of all, let me tell my problem.

There is power button and some other keys of a machine and there is only one user has authentication to use this machine.There are no other authentication methods, the machine is in public area in a company.

the machine is working with the combination of pressing power button and some other keys. The order of pressing keys is secret but we don't trust it, anybody can learn the password and can access the machine.

i have the capability of managing the key hold time and also some other metrics to measure the time differences between the key such as horizantal or vertical key press times (differences). and also i can measure the hold time etc.

These all means i have some inputs,

Now i'm trying to get a user profile by analysing these inputs.

My idea is to get the authenticated user to press the password n times and create a threshold or something similar to that.

This method also can be said BIOMETRICS, anyone else who knows the machine button combination, can try the password but if he is out of this range can not get access it.

How can i adapt these into my algorithms? where should i start ?

i don't want to delve deep into machine learning, and also i can see the in my first try i can get false positive and false negative values really high, but i can manage it by changing my inputs.

thanks.