[ntfsd] Re[2]: transparent encryption file system driver enctrypted flag

It’s true,I have consulted lots of references like WDK example.But there’s no way show me to modify data in the driver.
My filter dirver is based on sfilter.All functions have completed exept set encrypted flag.So,I show my methods for some suggestion.Actually,I have generated another as the flag.But when i move the encrypted file to another folder,this flag is no help for me.

发件人: David Craig
收件人: Windows File Systems Devs Interest List
已发送: 2009/5/8(周五), 上午12:48:20
主题: Re:[ntfsd] Re[2]: transparent encryption file system driver enctrypted flag

Any form of data modifying file system filter or minifilter is difficult.
There are no samples in the WDK and AFAIK no really good ones available
anywhere on the Internet. The two most difficult are encryption and
compression with trying to do both bringing another level of complexity to
the design even if not to the code. Most designs for encryption are rather
pathetic and don’t handle key management properly.

If you are paranoid:
1. Use a Smartcard with PKI built into the card.
2. Use an authenticating server to validate the Smartcard and user.
3. Use a different session/symmetric key for each file.
4. Pass the encrypted session/symmetric key to the Smartcard to decrypt it
using the private key.

“Ladislav Zezula” wrote in message news:xxxxx@ntfsd…
> Is fs filter so difficult? :slight_smile:

Depends on what kind of fs filter. If you want to write
an “observation” FS filter, then it’s fairly easy and the examples
are in the WDK. As for any data-modification filter, then yes,
they are pretty complex and hard to do right.


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