phc-discussions - Re: [PHC] IETF draft

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Date: Tue, 10 Dec 2013 17:56:35 +0000
From: "Poul-Henning Kamp" <phk@....freebsd.dk>
To: discussions@...sword-hashing.net, CodesInChaos <codesinchaos@...il.com>
Subject: Re: [PHC] IETF draft

In message <CAK9dnSyyQuQp2fMVBcG15HK-apHyOYNECWezzU4tJ23VguQhzw@...l.gmail.com>
, CodesInChaos writes:

>On Tue, Dec 10, 2013 at 6:45 PM, Poul-Henning Kamp <phk@....freebsd.dk> wrote:
>>         output = slow_hash(site_key + salt + password)
>
>Personally I prefer output = encrypt(site_key, slow_hash(salt, password)). Since

Disadvantage:  If they get hold of the site_key, which I consider
almost a certainty if they got hold of your stored passwords, you're
back where we are today.

By mixing the site_key into the hash, you effectively prevent any
pre-computation, until after the attack has handed them the site_key.

-- 
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.