Make app secure

[JoachimDunkel]

Currently credentials are stored in a plane txt file.

On solution would be on first startup to ask for su - password to start the app.
This password can be used to encrypt and decrypt the credentials file. (still not 100 secure because the password lives then in memory in plane text but much better).

But then how to check if the sudo password was correct ?
Password in -> hash it -> salt and pepper it and compare to the stored hash?