You can do as much customization as you like, there is no encryption which would prevent you from doing so. You can see some great examples in the
AppThemes customer showcase of sites that have been modified from the default theme. So yes, technically it is possible to carry out the changes you describe, and in doing so we recommend the use of a
child theme in order to save from losing all the changes you have made in the process of an update. Child themes can only be used one at a time. Thanks.
