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Please check out this article from Jon Callas, PGP CTO, on factoring:
http://www.pgp.com/newsroom/ctocorner/factoring.html


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- -----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Patrick Cahalan
Sent: Friday, June 22, 2007 12:17 PM
To: [email protected]
Subject: Re: [FDE] compelling reason to do FDE in lieu of EFS?

> Does anyone have experience with this service or similar 
> password-breaking utilities?

Yes, I've used a few.

> Can a non-trivial login password be broken in mere days, or is
>  the high success rate of loginrecovery.com due to the weak 
> passwords (with predicable patterns or letter-number 
> substitutions) that people tend to use?

Both.  Either.  It depends :)

Do you have the hash of the password?  Do you know how it is
encrypted (MD5, DES, SHA-1, SHA-256, RC5)?  Was there salt added?
How strong is the password itself?

"login password" can be a loaded term -> does the machine
prohibit multiple wrong attempts?  Do I have local access to the
machine, and can I yank out the drive or otherwise attack the
stored crypts directly or do I need to try remotely?

A 56-bit DES hash was broken in 1998 in 56 hours, using a machine
that cost a quarter-million dollars to build; following the 18
month cycle version of Moore's Law, you could accomplish the same
task today in 56 hours with about $14K worth of hardware.
Practically, it's probably feasible to blow through older hash
functions using a $2,000 dual core machine in a couple of days at
most, using strict brute-force (no dictionary) methodologies.

I haven't looked at loginrecovery.com, but most password-crackers
don't really take a brute force approach anymore, since very few
people actually use truly random passwords; as you point out,
predictable patterns make building a good password cracker a
matter of running through a dictionary first.

A password that's been encrypted by a 128 bit function is
practically cracked about as quickly as one encrypted by an older
key if the password is weak; your cracking algorithm is going to
be using the same dictionary regardless - the cracker isn't
attacking the hash, it's just trying combinations of usernames
and passwords.

Functionally, this is a major question for people who are looking 
to deploy FDE in the future: how do you prevent someone who has 
access to the machine from busting in by brute force?  If the 
user gets to choose his own password, an FDE-protected machine 
can fall easily if the password is "password".

And, of course, if you make it too hard to remember, the user of 
the laptop is going to tape it to the underside of the laptop, so 
that he's not locked out on the road.  "Check for a stickynote 
under the keyboard" will probably still be a viable attack scenario.

> Anyone have personal experience with this that they'd like to 
> share?

I'm awaiting this paper discussed in this article, I hope it gets
into IEEE, since I'd really like more details as to the
background setup of the story:

http://www.darkreading.com/document.asp?doc_id=117302

Even the sparse writeup in the article is illuminating.
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