Re: password protect encrypted directory

["Kelly D. Lucas" <lucaskeli () fastmail fm>]

Windows XP support the Encrypted File System [EFS], as you probably 
already know. I think once someone has physical access, most security 
mechanisms will fail. I use OpenSSL to encrypt files, and when used with 
the 3DES algorithm, I think it will provide good security, and require a 
password to decrypt the file.

The problem, is that once the file is decrypted, if it is altered it 
would need to be encrypted again, and the decypted file deleted. This 
would need to happen every time, and by the user of the file.

If a user has physical access, and you cannot assume that the 
authenticated user is actually that user, this becomes a much more 
difficult problem to solve.  It breaks the MicroSoft security model, and 
unless the password is of sufficient length, a brute-force attack would 
break into it soon enough.

Lucas

K.D. Lucas
lucaskeli () fastmail fm



> -----Original Message-----
> From: Dana Rawson [mailto:absolutezero273c () nzoomail com] 
> Sent: Thursday, August 12, 2004 12:38 PM
> To: security-basics () securityfocus com
> Subject: password protect encrypted directory
>
>
>
> G'Day, all.
>
>
>
> Hope this isn't too basic of an issue but I wanted to ask for your direction
> if possible.
>
>
>
> Preface: I have directory which contains sensitive data on a w2k/xp laptop.
> I have the directory and files residing within encrypted. 
>
>
>
> Issue: I would like to password protect this directory so even the user who
> is logged into this profile is prompted for a password prior to gaining
> access to this data.
>
>
>
> Desired outcome: By accomplishing this (if possible) I wish to deny access
> to this data via remote entry/being hacked, and also protect the data should
> the laptop be stolen, or someone walks away from their computer without
> locking it (i.e. ctrl-alt-del) leaving it wide open for someone to sit down
> and start playing.
>
>
>
> Is this something that can be accomplished?  Is there commercial or
> opensource software available?
>
>
>
> I have found software on the web that states it can password protect a
> directory, but with out installing and testing all of them how can I know if
> it most secure?  Has anyone tested or reviewed this type of software?  
>
>
>
> Is anyone familiar with this that might make a recommendation?
>
>
>
> Thanks again in advance for your time.
>
>
>
> Regards,
>
> Dana
>
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---------------------------------------------------------------------------
Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off 
any course! All of our class sizes are guaranteed to be 10 students or less 
to facilitate one-on-one interaction with one of our expert instructors. 
Attend a course taught by an expert instructor with years of in-the-field 
pen testing experience in our state of the art hacking lab. Master the skills 
of an Ethical Hacker to better assess the security of your organization. 
Visit us at: 
http://www.infosecinstitute.com/courses/ethical_hacking_training.html
----------------------------------------------------------------------------