Correct. This is known as "plaintext equivalence" in the literature.
In your case #2, an attacker need not have the actual password;
obtaining the hash of the password will allow spoofing ability
equivalent to the intended user. This is often the case in simple
shared-secret schemes like this, and the reason that other
technologies like one-time passwords, public key crypto and SRP (see
RFC 2945) are used when the authentication database is at risk of
being compromised.
--Pete
Pete Wenzel <>
Senior Architect, SeeBeyond
Standards & Product Strategy
+1-626-471-6311 (US-Pacific)
Thus spoke Ronald van Kuijk () on Tue, Oct 07, 2003 at 01:20:01AM +0200:
> I'm no real security expert but as you describe it, aren't the security
> risks the same with both?
> 1. Base64(SHA-1(nonce + created + password))
> 2. Base64(SHA-1(nonce + created + SHA-1(password)))
> In case 1 you store it cleartext on the server and and use it cleartext
> on the client side
> In case 2 you store it sha-1 on the server and use it sha-1 on the
> client side
>
> In both cases you could steal the content of e.g. the ldap server and
> get into the system. The issue, imho, IS what is send over the network
> and not (mainly) what is stored. You own the machine it is stored on (in
> most cases) you do not however own the network.
>
> Ronald
>
> > -----Oorspronkelijk bericht-----
> > Van: eclogue chang [mailto:]
> > Verzonden: dinsdag 7 oktober 2003 0:24
> > Aan:
> > Onderwerp: [wss-comment] Password Digest
> >
> >
> > UsernameToken Profile, working draft 4, 11/08/2003,
> > Line 106-108 talks about digested password offers no
> > additional security. Did I miss something here? The
> > issue is not what is sent over the network; instead it
> > is how the services side compares the password. If the
> > clear text password is used, then the Services
> > Provider has to store the clear text password for
> > password validation. This is a security issue.
> >
> > Also, Line 119 Password_Digest = Base64(SHA-1(nonce +
> > created + password)) has the same problem. In this
> > case, the Service Provider unable to store hashed
> > password, instead it has to store the clear text
> > password in its database. This will create a big
> > security issue.
> >
> > If the password digest change to the follow, then this
> > issue goes away.
> >
> > Password_Digest = Base64(SHA-1(nonce + created +
> > SHA-1(password)))
> >
> > Can this suggestion be considered?
> >
> >
> > Eclouge Chang
