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From: Arno Wagner <arno@wagner.name>
To: dm-crypt@saout.de
Subject: Re: [dm-crypt] luksFormat Password Entropy
Date: Thu, 19 Aug 2010 15:54:55 +0200	[thread overview]
Message-ID: <20100819135455.GB18960@tansi.org> (raw)
In-Reply-To: <AANLkTikWpW1i99N1Vs72ahY-hBssGuTaePiNWD=HkOV5@mail.gmail.com>

Without looking at the details, the passphrase/password is 
basically hashed and hashing to concentrate entropy is 
something that works very well. 

So, no difference.

Incidentially, while 2.) has less entropy per bit, it does not
have less entropy per symbol (the whole password). If you
just say "entropy", in crypto that usually means the entropy of
the whole password/passphrase as it is perceived as one "symbol".

Confusing, I know and the respective communities all think
the usage is clear. 

Arno



On Wed, Aug 18, 2010 at 04:11:51PM -0400, Michael Matczynski wrote:
> For luksFormat, is there a difference in password strength between the
> following two passwords?
> 
> 1.) <256bitsecret>
> 
> 2.) <256bitsecret> | base64
> 
> Does the use of PBKDF2 make the longer but less entropy password #2
> equivalent to #1?
> 
> Thanks!
> Mike
> 
> 
> -- 
> Michael Matczynski
> e: mjm@alum.mit.edu
> w: www.zingtech.com
> w: www.catchwine.com
> _______________________________________________
> dm-crypt mailing list
> dm-crypt@saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt
> 

-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

If it's in the news, don't worry about it.  The very definition of 
"news" is "something that hardly ever happens." -- Bruce Schneier 

  reply	other threads:[~2010-08-19 13:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-18 20:11 [dm-crypt] luksFormat Password Entropy Michael Matczynski
2010-08-19 13:54 ` Arno Wagner [this message]
2010-08-19 14:28 ` Heinz Diehl
2010-08-19 15:23   ` Heinz Diehl
2010-08-19 18:35   ` Arno Wagner
2010-08-21  7:30     ` Heinz Diehl
2010-08-21 17:41       ` Arno Wagner

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