Re: Rekeying or just password change?

"ronys" <[email protected]> Fri, 11 Dec 2009 23:39:47 +0200
Newsgroups gmane.comp.security.passwordsafe.user
Message-ID <91D97119C60441D8A7C6942D3BB794A5@LYDIA>
 =

Excellent question.

Short answer: Each time the database is saved, the key used to encrypt the
records changes (to a new random value).

A "hash" of the password's used to encrypt the encryption key, so there's no
direct relation between the two. Note that if you think your master
password's been compromised, you should change *ALL* the passwords in your
database, as well as the master password, as soon as possible!
PasswordSafe's been designed under the assumption that the master password's
secure. If that's not the case, all bets are off...

Long answer: The PasswordSafe database format specification describes the
cryptographic implementation of PasswordSafe in full detail
(http://passwordsafe.svn.sourceforge.net/viewvc/passwordsafe/trunk/pwsafe/pw
safe/docs/formatV3.txt)

Cheers,

  Rony

-----Original Message-----
From: MSBsDkiUHF MSBsDkiUHF [mailto:[email protected]] =

Sent: Thursday, December 10, 2009 2:21 PM
To: [email protected]
Subject: [Passwordsafe-users] Rekeying or just password change?



Hi,
Let's say that - at some point of time a password repository is stolen and
the master password is either known or cracked.- to combat this, master
password is changed

Will the master password change the internal keying, e.g. future versions of
the same repository aren't decrypted?

I can think of a few ways this could be implemented,
MASTER_KEY =3D hash(MASTER_PASSWORD).In this implementation, master key will
change if MASTER_PASSWORD change.

MASTER_KEY =3D noise xor hash(MASTER_PASSWORD).In this implementation master
key could remain same upon password change (i.e. could be vulnerable)

So, ... how is it? is rekeying implemented to combat "old version stolen and
cracked" scenarios?
 		 	   		  =

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