If you want to change this in your site, just edit this list https://github.com/moodle/moodle/blob/master/mod/lti/backup/moodle2/backup_lti_stepslib.php#L64 in your copy of the code. Add
'resourcekey',
'password',somewhere. I don't think it is necessary to change the restore code. Please test this yourself before relying on it.