Re: Is the WinXP NTFS encryption secure?

Dear Antonio & friends:

Antonio Perez <ap23562m@xxxxxxx> wrote:

Juan I. Cahis jiclbchSINBASURA@xxxxxxxxxxxxx wrote previously in
alt.computer.security:

Dear friends:

Is the WinXP NTFS encryption secure?

Is it convenient to encrypt the folder "c:\Document and Settings\<My
Account>\" (and its subfolders) in order to avoid problems in the case
that your computer or your hard disk is stolen?

That's a bit difficult to answer in a general sense. It depends...

Background:
A folder encrypted with Win OS is secure as long as the attacker does _not_
have the password. That's the general accepted description. And, it's true.
The only way to decrypt a folder with an unknown password is to try them
all. That's called "brute force attack". It requires a lot of processing
power and patience to try all possible passwords.

But here is the catch: Who have the password stored?
Answer: The OS
This means that in the following events:
1.- The OS is compromised (virus, trojan, rootkit).
2.- Your user password gets cracked/guessed/revealed.
3.- There is a backdoor to the OS (???).
The password (to the encrypted folder) stored inside the OS is available to
the attacker. In this scenarios, the folder is decrypted, and your secrets
are revealed.

So, it depends... who you are guarding against:
Computer gets stolen: The password is somewhere inside the OS, it could be
found. Yes, with a lot of knowledge/work, but possible.

If the password is independent of the OS, the only vector of attack
is "brute force".

AP

Antonio, as a common person,I am not thinking to be protected from a
spy agency, but from standard bad intentioned people that they can
access my computer in the case it is stolen. I understand that
personal data, emails, etc. are stored in the folder that I mentioned
earlier, so my data will be protected. And because no programs are
stored there, I assume that the computer performance will not suffer
very much.

Am I correct?


Thanks
Juan I. Cahis
Santiago de Chile (South America)
Note: Please forgive me for my bad English, I am trying to improve it!
.

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