phc-discussions - Re: [PHC] IETF draft

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Date: Wed, 11 Dec 2013 10:20:10 +0000
From: "Poul-Henning Kamp" <phk@....freebsd.dk>
To: CodesInChaos <codesinchaos@...il.com>
cc: discussions@...sword-hashing.net
Subject: Re: [PHC] IETF draft

In message <CAK9dnSw3OJJVQw3AF+SYZuAuULrOc_sJkCLWk0e0LYdzOTwU8g@...l.gmail.com>
, CodesInChaos writes:

>> My 1994 proposal:
>>
>>         DB(salt, hash(site_key + salt + password))
>>
>> Frustrates that attack, even if the site_key is also stolen, because
>> there will not be any salt collisions -- as the site_key is
>> effectively a part of the salt.
>Why bother frustrating an already irrelevant attack?

And just why do you think I mentioned this idea in 1994, and then
did nothing with it ever since ?   :-)

>If you use the key as input to the slow hash, you can't store it on a
>low power device,

Neither can you if you need it to validate a password.

A password scrambler should not rely on secrecy, since that is almost
impossible to maintain if you want to be able to validate passwords.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@...eBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.