The XLT file is a valid Excel spreadsheet that's stored in a temporary directory on your machine. By giving the file an XLT extension, when you open the export and want to save the file, it will force the "Save As" dialog to pop up such that you can save the file to a location of your choice with a name of your choice. This allows us to remove the temporary copy once you close Excel.
If Isonas ID Files are deleted, we can no longer obtain all of the person details for the admission entries in your facility. We have to piece together information based on the badge ID in this situation. To keep reporting accurate, per Isonas recommendations, try and avoid deleting ID Files and instead put them in a 'Inactive' group.
We work with the password and encryption key as .NET SecureString objects in memory.