Re: [secdir] Sector review of draft-josefsson-scrypt-kdf-03

Simon Josefsson <simon@josefsson.org> Fri, 20 November 2015 12:31 UTC

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From: Simon Josefsson <simon@josefsson.org>
To: Joseph Salowey <joe@salowey.net>
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Date: Fri, 20 Nov 2015 13:30:56 +0100
In-Reply-To: <CAOgPGoBY9V-z5emqU6e=2QCGb_wfEUM-eE+KKgzDqg9jLAYVVw@mail.gmail.com> (Joseph Salowey's message of "Sun, 13 Sep 2015 16:36:29 -0700")
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Cc: draft-josefsson-scrypt-kdf.all@tools.ietf.org, secdir <secdir@ietf.org>
Subject: Re: [secdir] Sector review of draft-josefsson-scrypt-kdf-03
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Hi Joseph.  Thanks for your review, and sorry for the delay in answering
this.  In the new version [1] I have added a new section to discuss
scrypt parameters.

/Simon

[1] https://tools.ietf.org/html/draft-josefsson-scrypt-kdf-04

Joseph Salowey <joe@salowey.net> writes:

> I have reviewed this document as part of the security directorate's ongoing
> effort to review all IETF documents being processed by the IESG.  These
> comments were written primarily for the benefit of the security area
> directors and document authors.
>
> I think this document is ready with issues.   The document describes a
> password to key function, scrypt, based on memory hard functions to make it
> more expensive and difficult to develop specialized hardware to obtain the
> password from a recovered key.  I'd like to see this document published.  A
> few issues are listed below.
>
> First, I think Paul Kyzivat's GenArt review.
> http://mailarchive.ietf.org/arch/msg/gen-art/fToZiioHo-6x5ZRQWNcTr-aUYVk
> <https://mailarchive.ietf.org/arch/msg/gen-art/fToZiioHo-6x5ZRQWNcTr-aUYVk>,
> raised
> some points that could help the readability of the document.
>
> Second, the script algorithm has several parameters, but the document has
> very little discussion on how to choose those parameters or what they
> affect (this is also pointed out in Paul's message).  It would be good to
> have some discussion or guidance for parameter selection in the security
> considerations.
>
> Cheers,
>
> Joe
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