Information is only held for as long as there is a legitimate reason to do so, information that is no longer required is destroyed in such a way that it cannot be reconstructed.
Caiff gwybodaeth ond ei chadw cyhyd â bod rheswm cyfreithiol i wneud hynny, a chaiff gwybodaeth nad oes ei hangen mwyach ei dinistrio mewn ffordd na ellir ei hail-greu.