Based on what NetScan can do, achieve, and keep inside its layout and config, is there any possibility to implement some kind of an optional security method to guard access to its GUI? Can, for example, config files can be encrypted?
I may not be quite sure what exactly you want to achieve, but encrypting config files would require some kind of master password to be entered every time the application is used. This is not something we'd like to add due to the difficulty of implementing encryption correctly and its effect on software export restrictions between jurisdictions.
If the security of config files is a concern for you, I would recommend creating an encrypted container using a proven solution, for example VeraCrypt, and placing a portable edition of the NetScan application together with its config files into it. Then, any sensitive data in the container would only be accessible when it's mounted with a correct password.