G PHYSICS
G06 COMPUTING OR CALCULATING; COUNTING
G06F ELECTRIC DIGITAL DATA PROCESSING
G06F21/00 Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
G06F21/60 Protecting data
G06F21/62 Protecting access to data via a platform, e.g. using keys or access control rules
G06F21/6218 to a system of files or objects, e.g. local or distributed file system or database