Hi,
I need some advice on storing file encryption attribute. Currently my
filter driver stores the encryption attribute in the file header with fixed
bytes. When I query a dir (e.g. from DOS ‘dir’ command), all the file sizes
show the encrypted sizes which are not correct, since I simply pass through
the dir request to the lower file system. However, in order to differentiate
whether the file is encrypted, the driver needs to open each file in
sequence and read the header information. This is very inefficient if the
dir contains many files. I am developing the driver in Win 2k and XP, and
the driver should attach to all type of devices including removable media,
local disks (FAT and NTFS) and network drives. So the approach should be
generic enough and not tied to particular file system. I am thinking of
changing the filename to differentiate the encrypted attribute, is there any
potential problem? Please give some advices on any better approach to store
the attribute. Thanks for any information!
Regards,
Sin-Lam