I will assume that you want to do this for every document type supported by
Microsoft applications include Office 97 onward. This will take at least
three man years of work. I also assume you have the IFS Kit. I also assume
you want to support NT 4.0 SP6a onward including Windows Server 2003. Take
the sfilter example and add code to track file creations/opens, deletions,
reads/writes, renames, cleanups, and closes. Run the various applications
doing a multitude of things. You might hire several users ranging in
experience from novice to expert. Look at how each application handles each
file type and operation from just an open to read, a recovery of a doc where
the computer was rebooted during editing, small changes to major changes.
Turn on and off the storing of changes in doc files especially and see how
it works.
BTW, I have some bad news to follow the good news: Some applications go
through two or more work files that are hard to identify as being the data
from the original file. In fact, one app will close and delete the original
file before the next work file is created. Been there, done that. Might be
easier to implement whole drive encryption - it will be much easier because,
been there, done that.
Anyone know anything about encryption or are you just guessing? Complicated
issues on key management, generation, etc.
“Manav Khanna” wrote in message news:xxxxx@ntfsd…
>
> hi,
>
> I will try to express myself better here. What I am
> trying to implement should work as follows:
>
> 1) A file exists on disk in an encrypted format. Let’s
> say an encrypted word doc.
> 2) When I open the encrypted file, my module should
> decrypt the encrypted file on-the-fly (without storing
> the decrypted bytes in another .doc file on the disk)
> and present the decrypted data to the relevant
> application (Microsoft word in this case).
> 3) That is to say, encryption and decryption is
> performed everytime a file is read from or written to,
> such that what exists on the disk is only the
> encrypted file. The decrypted data is never stored on
> the disk.
>
> I would greatly appreciate pointers and general
> suggestions about articles and other information
> available to help me get started on this.
>
> Thanks in advance,
> Rgds,
> -Manav
>
> — Prokash Sinha wrote:
> > But you will have to have Ur own viewer…
> >
> > -prokash
> > ----- Original Message -----
> > From: “David J. Craig”
> > Newsgroups: ntfsd
> > To: “File Systems Developers”
> > Sent: Monday, August 18, 2003 5:37 PM
> > Subject: [ntfsd] Re: In-memory Decryption of
> > encrypted files
> >
> >
> > > If you meant what you said, the answer is simple.
> > Write your own OS. No
> > > can do with Windows NT, 2000, XP, and 2003.
> > Normally data from a file is
> > > not written to the paging file unless the data has
> > been modified. It is
> > > easier to just reread the source data.
> > >
> > > Quit with the HTML.
> > >
> > > “Manav Khanna” wrote in
> > message
> > news:xxxxx@ntfsd…
> > > Hi all,
> > >
> > > I need to implement a module that decrypts
> > encrypted files in memory and
> > > presents the decrypted data in the viewing
> > application ( for example,
> > > display in Notepad, the data decrypted from an
> > encrypted file without
> > > buffering the decrypted bytes into a file on
> > disk).
> > >
> > > I would greatly appreciate pointers and general
> > suggestions about articles
> > > and other information available to help me get
> > started on this.
> > >
> > > Thanks in advance,
> > > Rgds,
> > > -Manav
> > >
> > >
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