[pLog-svn] Salted MD5

Matt Wood matt at woodzy.com
Mon Mar 10 15:22:40 EDT 2008


The only reason you would salt passwords in a database means your concerned
that the password db table has been compromised... if you fear that has
happened then the salt that your storing in the database is available to the
attacker. Thus adding md5 or sha1 or sha256 of that salt to the password is
no more secure than just appending the salt in plaintext. The same number of
computations will be required to "crack" the password hash.

-Matt

PS. md5/sha1 are not cryptographically secure hash algorithms anymore
(however probably are ok for this situation). any sha2 algorithm (sha256,
sha512) is suposedly.

On Mon, Mar 10, 2008 at 11:32 AM, Mark Wu <markplace at gmail.com> wrote:

> >
> >       How much more secure is than simply:
> >
> > md5($password . $private_key)
>
> Actually, it's no difference for normal people, but much secure for those
> hackers...
>
> BTW, VBB and IPB use:
>
> md5(md5($password).md5($private_key))
>
> >
> > And are there any downsides of the new method - ie. will it
> > fail on upgrades, or fail for certain servers, etc?
> >
>
> mmm .... for lifetype 2.0 . The minimal requirement is php 5.1.x ...
>
> so, It won't be a problem.
>
> mhash become "hash" in pecl in php5, if there is no hash installed, it
> will
> use the pure php  implementation...
>
> >
> > On Mon, 10 Mar 2008, Mark Wu wrote:
> >
> > > Here comes more secure algorithm:
> > >
> > > sha256(md5($password)+md5($your_provide_private_key));
> > >
> > > I use sha256 here.
> > >
> > > Here also comes the pure php sha256 implementation:
> > >
> > > http://nanolink.ca/pub/sha256/
> > >
> > > If the server has "hash" pecl, it will use it instead of
> > the pure one.
> > >
> > > Mark
> > >
> > >> -----Original Message-----
> > >> From: plog-svn-bounces at devel.lifetype.net
> > >> [mailto:plog-svn-bounces at devel.lifetype.net] On Behalf Of Reto Hugi
> > >> Sent: Monday, March 10, 2008 7:25 PM
> > >> To: LifeType Developer List
> > >> Subject: Re: [pLog-svn] Salted MD5
> > >>
> > >> Hi Mark
> > >>
> > >> I welcome your suggestion and think that this is valuable
> > >> protection against rainbow table attacks.
> > >>
> > >> We already had an issue with the revealed admin password
> > >> hash. This would have been less severe with the saltet md5.
> > >>
> > >> Thanks for suggesting!
> > >>
> > >> reto
> > >>
> > >> Mark Wu wrote:
> > >>> Hi All:
> > >>>
> > >>> I plan to upgrade our password algorithm to salted MD5, take the
> > >>> following for eaxample:
> > >>>
> > >>> sha1(md5($password) + user_defined_private_key);
> > >>>
> > >>> I will also remain an option in lifetype admin panel for
> > >> user to use
> > >>> the old MD5 way to keep compatability.
> > >>>
> > >>> If we use the algorithm above, It is also possible to
> > >> convert the old
> > >>> hashed password to new hased password.
> > >>>
> > >>> How do you think?
> > >>>
> > >>>
> > >>
> > http://kuza55.blogspot.com/2006/10/online-reverse-lookup-tables-for.ht
> > >>> ml
> > >>>
> > >>> These kind of online reverse lookup table sites making
> > the MD5 only
> > >>> algorithm more dangerous.
> > >>>
> > >>> Mark
> > >>>
> > >>>
> > >>>
> > >>>
> > >>>
> > >>
> > ----------------------------------------------------------------------
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> > >>>
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> >
> > --
> > Jon Daley
> > http://jon.limedaley.com/
> >
> > We are all made different, but we are all sinners.
> > -- Jim Herron
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