@Borbosch lead you the correct way on how to test your cypher strength.
Simply create the file and run it using the text he gave you.
This will show you about the status of the key length supported on your installation.
If it’s to short it won’t work.
As mentioned before I’m not a docker expert, but there is at least an environment variable to be set. Some more info in this post.
To be honest: If you are missing the very basic Linux knowledge it will be hard to maintain your OH installation.
Maybe start with a Windows based setup first and learn how to handle OH itself would be the better way to start.
Or, as an alternative, run OH on a Raspberry PI based on the openhabian setup routines. This will install everything you need without first learning to handle Linux in detail.
