as each write comes into the driver you’d encrypt the data in a new
buffer, then send a write with the new buffer. As each read comes into
the driver you’d let it run then decrypt the data and complete it.
(can you tell me why you should put the encrypted data in a new buffer
raher than encrypting it in place?)
all reads and writes to the disk driver will be in increments of sector
size. You can use IOCTL_DISK_GET_GEOMETRY to find the sector size. The
file system retrieves data from the disk by calling the disk driver - if
you’re a filter in that stack then you’ll be part of that call.
you may want to consider doing sector-wise encryption at the volume
level rather than the partition level. It seems more likely that you
want to encrypt c: and not just one of the disks that makes up the
stripe-volume that c: points to. but i may be wrong.
read the DDK documentation on disk drivers. read some of the other
books out there on driver development. get a feeling for how filters
work, how the disk stack works, and how it interacts with other
components. This may allow you to ask more specific questions then “how
do i design a driver to encrypt the disk”.
good luck,
-p
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of vartika singh
Sent: Wednesday, June 09, 2004 8:38 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Sector wise encryption/decryption
Hi,
Earlier i posted a question regarding capturing data at the disk
partition upper filter driver level.
I need some help to begin with the sector-wise encryption and decryption
of that particular partition and it is not the boot partition.
I know my question sounds quite vague but i myself dnt have any idea as
to how to begin with.
I can do byte level enc-dec.
But how to move it to sector level,i just need some idea as to how to
begin with.
How will the FS retrieve data if the sector is encrypted and what
additional capabilities do i have to add to my filter.
Please do respond
regards
V.S.
http: — Questions?
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