Mini filter and encryption related query (Not a core mini filter issue)

NTFSD
1

Hi,

I have written a simple mini filter (using Microsoft IFS kit) which
encrypts the data using a trivial encryption algorithm. Now I would like to
use an industry standard algorithm e.g. RSA, MD5, BlowFish etc. I had
following questions.

  1. Where should I place the functions that will perform the crypt
    logic?

  • In the driver itself. (Don’t think this is good).

  • Create a C library and link the driver with this library. (Can
    this be done? What are the constraints on the library so that it can be used
    by the driver?).

  • Put the crypt functions in the user mode service. (Simple. But
    overhead involved in moving data back and forth from the driver and user
    mode service.).

  1. Are there any 3rd party libraries available (free or licensed)?

  • OpenSSL.

  • BeeCrypt (not been tested for Windows 2003).

  • Fips.sys (not officially supported).

  • Any other that you know of.

What is the kind of effort involved out here?

Please let me know if I am missing out on anything here.

Thanks,

Vishal

2

Hi,

Could anybody help me on this?

Thanks in advance,

Vishal

From: Vishal Pai [mailto:xxxxx@persistent.co.in]
Sent: Thursday, April 06, 2006 8:22 PM
To: ‘xxxxx@lists.osr.com’
Subject: Mini filter and encryption related query (Not a core mini filter
issue)

Hi,

I have written a simple mini filter (using Microsoft IFS kit) which
encrypts the data using a trivial encryption algorithm. Now I would like to
use an industry standard algorithm e.g. RSA, MD5, BlowFish etc. I had
following questions.

  1. Where should I place the functions that will perform the crypt
    logic?

  • In the driver itself. (Don’t think this is good).

  • Create a C library and link the driver with this library. (Can
    this be done? What are the constraints on the library so that it can be used
    by the driver?).

  • Put the crypt functions in the user mode service. (Simple. But
    overhead involved in moving data back and forth from the driver and user
    mode service.).

  1. Are there any 3rd party libraries available (free or licensed)?

  • OpenSSL.

  • BeeCrypt (not been tested for Windows 2003).

  • Fips.sys (not officially supported).

  • Any other that you know of.

What is the kind of effort involved out here?

Please let me know if I am missing out on anything here.

Thanks,

Vishal

3

> Where should I place the functions that will perform the crypt logic?

For every crypt algorithm you can create separate driver and load this drivers from your main driver.

Best regards,
Victor Fisyuk
EMail/MSN: xxxxx@rambler.ru
Web: http://rockdbg.siteburg.com
“Vishal Pai” wrote in message news:xxxxx@ntfsd…
Hi,

I have written a simple mini filter (using Microsoft IFS kit) which encrypts the data using a trivial encryption algorithm. Now I would like to use an industry standard algorithm e.g. RSA, MD5, BlowFish etc. I had following questions.

1… Where should I place the functions that will perform the crypt logic?
- In the driver itself. (Don’t think this is good).

- Create a C library and link the driver with this library. (Can this be done? What are the constraints on the library so that it can be used by the driver?).

- Put the crypt functions in the user mode service. (Simple. But overhead involved in moving data back and forth from the driver and user mode service.).

2… Are there any 3rd party libraries available (free or licensed)?
- OpenSSL.

- BeeCrypt (not been tested for Windows 2003).

- Fips.sys (not officially supported).

- Any other that you know of.

What is the kind of effort involved out here?

Please let me know if I am missing out on anything here.

Thanks,

Vishal

4

> For every crypt algorithm you can create separate driver and load this
drivers from your main driver.

The popular name for this kind of approach is, “Export Drivers”

On 4/10/06, Victor Fisyuk wrote:
>
> > Where should I place the functions that will perform the crypt logic?
>
> For every crypt algorithm you can create separate driver and load this
> drivers from your main driver.
>
> Best regards,
> Victor Fisyuk
> EMail/MSN: xxxxx@rambler.ru
> Web: http://rockdbg.siteburg.com
>
> “Vishal Pai” wrote in message
> news:xxxxx@ntfsd…
>
> Hi,
>
>
>
> I have written a simple mini filter (using Microsoft IFS kit) which
> encrypts the data using a trivial encryption algorithm. Now I would like to
> use an industry standard algorithm e.g. RSA, MD5, BlowFish etc. I had
> following questions.
>
>
>
> 1. Where should I place the functions that will perform the crypt
> logic?
>
> - In the driver itself. (Don’t think this is good).
>
> - Create a C library and link the driver with this library. (Can
> this be done? What are the constraints on the library so that it can be used
> by the driver?).
>
> - Put the crypt functions in the user mode service. (Simple. But
> overhead involved in moving data back and forth from the driver and user
> mode service.).
>
>
>
> 1. Are there any 3rd party libraries available (free or licensed)?
>
>
> - OpenSSL.
>
> - BeeCrypt (not been tested for Windows 2003).
>
> - Fips.sys (not officially supported).
>
> - Any other that you know of.
>
>
>
> What is the kind of effort involved out here?
>
>
>
> Please let me know if I am missing out on anything here.
>
>
>
> Thanks,
>
> Vishal
>
>
> —
> Questions? First check the IFS FAQ at
> https://www.osronline.com/article.cfm?id=17
>
> You are currently subscribed to ntfsd as: unknown lmsubst tag argument: ‘’
>
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>

5

> - In the driver itself. (Don’t think this is good).

I would go this way. The lesser binaries in the project, the better, the
simpler is the support.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

6

Hi,

Thanks to all for your suggestions (I looked at this post just today.).

I tried both the approaches (i.e. having crypt in the filter as well as
in other driver). The first approach seemed to be simpler for my
requirements as suggested by Maxim. I am using the reasonably secure crypt
algorithm called Blow-Fish for my current implementation.

Thanks again,

Vishal

From: Vishal Pai [mailto:xxxxx@persistent.co.in]
Sent: Thursday, April 06, 2006 8:22 PM
To: ‘xxxxx@lists.osr.com’
Subject: Mini filter and encryption related query (Not a core mini filter
issue)

Hi,

I have written a simple mini filter (using Microsoft IFS kit) which
encrypts the data using a trivial encryption algorithm. Now I would like to
use an industry standard algorithm e.g. RSA, MD5, BlowFish etc. I had
following questions.

  1. Where should I place the functions that will perform the crypt
    logic?

  • In the driver itself. (Don’t think this is good).

  • Create a C library and link the driver with this library. (Can
    this be done? What are the constraints on the library so that it can be used
    by the driver?).

  • Put the crypt functions in the user mode service. (Simple. But
    overhead involved in moving data back and forth from the driver and user
    mode service.).

  1. Are there any 3rd party libraries available (free or licensed)?

  • OpenSSL.

  • BeeCrypt (not been tested for Windows 2003).

  • Fips.sys (not officially supported).

  • Any other that you know of.

What is the kind of effort involved out here?

Please let me know if I am missing out on anything here.

Thanks,

Vishal