Hai all,
Please help me to solve the following problem…
My requirement is like this.
I have an application(container) which embbed Mocrosoft word. I want to encrypt the files when it is saved by word, and should be able to decrypt it back when the MSword reads it back. (ie, in the disk, the file should be in the encrypted form).
- Which method will u suggest? A UserMode API hooking or an encryption Filter Driver?
In both the methods, I want to identify the file which should be encrypted and which should not be. will filename alone will do ? can u suggest a good method?
- can u suggest some links or resources from where i can read more about this (encryption filter drivers and the issues that should be considered while writing an encryption filter driver) ?
Thanks,
Deepu.L.R,M2
As I haven’t worked much OLE containers with Word, I am not aware if
you can directly interact with the saving or loading process.
So, I think a filter will be required.
I was unable to find virtually any documentation that is specific to
encryption filters or that helps writing one, aside from having the
basic filter issues explained. You may want to check the OSR IFS Kit FAQ
list, since it does have a question or two that are helpful.
–
Kind regards, Dejan M. www.alfasp.com
E-mail: xxxxx@alfasp.com ICQ#: 56570367
Alfa File Monitor - File monitoring library for Win32 developers.
Alfa File Protector - File protection and hiding library for Win32
developers.
Alfa Registry Monitor - Registry monitoring library for Win32
developers.
Alfa Registry Protector - Registry protection library for Win32
developers.
hai Dejan…and others
Thanks for the suggesion,
leave the OLE containers part, in my problem there is not much
importance for it.
ok, in case of a filter, it will be placed just above the FileSystem
driver, and all the filesystem calls will go through my driver… right. so
in my filter i should identify the filename which should be encrypted
(during IRP_MJ_CREATE).
suppose, i want to encrypt the file 'x.txt ’ from the Application ‘A’.
so my filter driver should know that, encryption should be applied only if
it is from application ‘A’ and provided that, the filename should be ‘x.txt’
right. ie, i should pass some parameter to the filter (like process ID or
some other value) that can be used to uniquely identify the process ‘A’. if
am in the right direction i have following doubts…
-
what are the values that can be used uniquely identify a particular file
from a particular process inside the filter?
-
Will it be good to use IRP_MJ_DEVICE_CONTROL to pass the above said
values to the filter dirver.
Thanks in advace,
Deepu.L.R,M2
----- Original Message -----
From: “Dejan Maksimovic”
To: “File Systems Developers”
Sent: Friday, July 05, 2002 3:40 PM
Subject: [ntfsd] Re: Encryption Method
>
> As I haven’t worked much OLE containers with Word, I am not aware if
> you can directly interact with the saving or loading process.
> So, I think a filter will be required.
> I was unable to find virtually any documentation that is specific to
> encryption filters or that helps writing one, aside from having the
> basic filter issues explained. You may want to check the OSR IFS Kit FAQ
> list, since it does have a question or two that are helpful.
>
> –
> Kind regards, Dejan M. www.alfasp.com
> E-mail: xxxxx@alfasp.com ICQ#: 56570367
> Alfa File Monitor - File monitoring library for Win32 developers.
> Alfa File Protector - File protection and hiding library for Win32
> developers.
> Alfa Registry Monitor - Registry monitoring library for Win32
> developers.
> Alfa Registry Protector - Registry protection library for Win32
> developers.
>
>
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@m2comsys.com
> To unsubscribe send a blank email to %%email.unsub%%
>
I expect Word to use Stgxxx functions from OLE32.DLL to work with DOC files.
Hook them (in Word’s IAT, for instance). This is much simpler then kernel-mode development.
Max
----- Original Message -----
From: Deepu.L.R
To: File Systems Developers
Sent: Friday, July 05, 2002 1:25 PM
Subject: [ntfsd] Encryption Method
Hai all,
Please help me to solve the following problem…
My requirement is like this.
I have an application(container) which embbed Mocrosoft word. I want to encrypt the files when it is saved by word, and should be able to decrypt it back when the MSword reads it back. (ie, in the disk, the file should be in the encrypted form).
- Which method will u suggest? A UserMode API hooking or an encryption Filter Driver?
In both the methods, I want to identify the file which should be encrypted and which should not be. will filename alone will do ? can u suggest a good method?
- can u suggest some links or resources from where i can read more about this (encryption filter drivers and the issues that should be considered while writing an encryption filter driver) ?
Thanks,
Deepu.L.R,M2
You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
To unsubscribe send a blank email to %%email.unsub%%
Deepu.L.R wrote:
Hai all,
Please help me to solve the following problem…
My requirement is like this.
I have an application(container) which embbed Mocrosoft word. I want to
encrypt the files when it is saved by word, and should be able to
decrypt it back when the MSword reads it back. (ie, in the disk, the
file should be in the encrypted form).
- Which method will u suggest? A UserMode API hooking or an encryption
Filter Driver?
In both the methods, I want to identify the file which should be
encrypted and which should not be. will filename alone will do ? can u
suggest a good method?
- can u suggest some links or resources from where i can read more
about this (encryption filter drivers and the issues that should be
considered while writing an encryption filter driver) ?
Thanks,
Deepu.L.R,M2
Deepu,
I don’t know how long you have to write this, but an encrypting filter
driver is several months work, and probably longer to be sure it is
working OK on all platforms and with all the other filters. It’s a bit
of a black art to get the decryption for one app and not the others.
(come to that file systems in general are a black art!)
If it is just WORD, Max’s approach is probably a better bet.
Andy.
max,
thanks for the hint… in that case i think i have to hook IStorage and IStream Interface functions also.
Thanx
Deepu.L.R,M2
----- Original Message -----
From: Maxim S. Shatskih
To: File Systems Developers
Sent: Saturday, July 06, 2002 3:09 PM
Subject: [ntfsd] Re: Encryption Method
I expect Word to use Stgxxx functions from OLE32.DLL to work with DOC files.
Hook them (in Word’s IAT, for instance). This is much simpler then kernel-mode development.
Max
----- Original Message -----
From: Deepu.L.R
To: File Systems Developers
Sent: Friday, July 05, 2002 1:25 PM
Subject: [ntfsd] Encryption Method
Hai all,
Please help me to solve the following problem…
My requirement is like this.
I have an application(container) which embbed Mocrosoft word. I want to encrypt the files when it is saved by word, and should be able to decrypt it back when the MSword reads it back. (ie, in the disk, the file should be in the encrypted form).
- Which method will u suggest? A UserMode API hooking or an encryption Filter Driver?
In both the methods, I want to identify the file which should be encrypted and which should not be. will filename alone will do ? can u suggest a good method?
- can u suggest some links or resources from where i can read more about this (encryption filter drivers and the issues that should be considered while writing an encryption filter driver) ?
Thanks,
Deepu.L.R,M2
You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
To unsubscribe send a blank email to %%email.unsub%%
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----- Original Message -----
From: “Andy Champ”
Newsgroups: ntfsd
To: “File Systems Developers”
Sent: Tuesday, July 09, 2002 2:04 PM
Subject: [ntfsd] Re: Encryption Method
> Deepu.L.R wrote:
>
> > Hai all,
> >
> >
> >
> > Please help me to solve the following problem…
> >
> >
> >
> > My requirement is like this.
> >
> >
> >
> > I have an application(container) which embbed Mocrosoft word. I want to
> > encrypt the files when it is saved by word, and should be able to
> > decrypt it back when the MSword reads it back. (ie, in the disk, the
> > file should be in the encrypted form).
> >
> >
> >
> > 1) Which method will u suggest? A UserMode API hooking or an encryption
> > Filter Driver?
> >
> >
> >
> > In both the methods, I want to identify the file which should be
> > encrypted and which should not be. will filename alone will do ? can u
> > suggest a good method?
> >
> >
> >
> >
> >
> > 2) can u suggest some links or resources from where i can read more
> > about this (encryption filter drivers and the issues that should be
> > considered while writing an encryption filter driver) ?
> >
> >
> >
> >
> >
> >
> > Thanks,
> >
> >
> > Deepu.L.R,M2
> >
>
> Deepu,
> I don’t know how long you have to write this, but an encrypting filter
> driver is several months work, and probably longer to be sure it is
> working OK on all platforms and with all the other filters. It’s a bit
> of a black art to get the decryption for one app and not the others.
> (come to that file systems in general are a black art!)
>
> If it is just WORD, Max’s approach is probably a better bet.
>
> Andy.
>
hai andy,
thanks for the reply
you are right, since, i don’t have several months for this work, i am
trying Max 's approch. I think, i am close to the target.
Thanks,
Deepu.L.R