Encryption in Minifilter

NTFSD
1

Hello,

I am doing Encryption(AES Algorithm) in minifilter and its perfectly working
for
MS Office 2007 and wordpad. But it is not working for MS Office 2003 and
Notepad
why?

2

Notepad uses memory-mapped files.

–
Maxim S. Shatskih
Windows DDK MVP
xxxxx@storagecraft.com
http://www.storagecraft.com

“Nisha Mudra Patel” wrote in message news:xxxxx@ntfsd…
Hello,

I am doing Encryption(AES Algorithm) in minifilter and its perfectly working for
MS Office 2007 and wordpad. But it is not working for MS Office 2003 and Notepad
why?

3

It sounds like your mini-filter is broken. I suspect you will find it doesn’t work with any application that uses memory mapped files. I bet it doesn’t work when you connect to network drives, either.

Tony
OSR

4

Thanks Tony, you are right it doesn’t work with network drives (but don’t want it to work
for n/w drives).

Could you pass me some pointers on what I should read up on to address Notepad and Word 2003.
Thanks,
…

5

A search on “memory mapped files” or just “encryption” on this list will answer your question.
If you didn’t find a search for the list, go to www.osronline.com, there is a search for NTFSD on the left side.
It’s very easy to miss - if you don’t want to spend time but ask others to spend time for you :wink:

xxxxx@gmail.com wrote:

Thanks Tony, you are right it doesn’t work with network drives (but don’t want it to work
for n/w drives).

Could you pass me some pointers on what I should read up on to address Notepad and Word 2003.
Thanks,
…

NTFSD is sponsored by OSR

For our schedule of debugging and file system seminars visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer

–
Kind regards, Dejan (MSN support: xxxxx@alfasp.com)
http://www.alfasp.com
File system audit, security and encryption kits.

6

You should only transform data buffers (encryption/decryption) for non-cached IO and Paged IO paths,
to ensure cache is always clear.

That way memory mapping applications work.

On Mar 19, 2011, at 1:19 AM, xxxxx@gmail.com wrote:

Thanks Tony, you are right it doesn’t work with network drives (but don’t want it to work
for n/w drives).

Could you pass me some pointers on what I should read up on to address Notepad and Word 2003.
Thanks,
…

NTFSD is sponsored by OSR

For our schedule of debugging and file system seminars visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer

7

The details of why and how’s are discussed in this forum extensively. Please use a search.

On Mar 19, 2011, at 10:00 AM, sridhar uyyala wrote:

You should only transform data buffers (encryption/decryption) for non-cached IO and Paged IO paths,
to ensure cache is always clear.

That way memory mapping applications work.

On Mar 19, 2011, at 1:19 AM, xxxxx@gmail.com wrote:

> Thanks Tony, you are right it doesn’t work with network drives (but don’t want it to work
> for n/w drives).
>
> Could you pass me some pointers on what I should read up on to address Notepad and Word 2003.
> Thanks,
> …
>
> —
> NTFSD is sponsored by OSR
>
> For our schedule of debugging and file system seminars visit:
> http://www.osr.com/seminars
>
> To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer