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Subject: Re: Raising the SCRAM iteration count
From: Daniel Gustafsson <daniel@yesql.se>
In-Reply-To: <4880738a-cbf7-c9a1-4faf-ba861c731c63@postgresql.org>
Date: Tue, 13 Dec 2022 12:17:58 +0100
Cc: Andres Freund <andres@anarazel.de>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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 <20221210001538.czikyvk3xtkphxfu@awork3.anarazel.de>
 <4880738a-cbf7-c9a1-4faf-ba861c731c63@postgresql.org>
To: "Jonathan S. Katz" <jkatz@postgresql.org>
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> On 12 Dec 2022, at 15:47, Jonathan S. Katz <jkatz@postgresql.org> =
wrote:

> To throw on a bit of paint, if we do change it, we should likely =
follow what would come out in a RFC.
>=20
> While the SCRAM-SHA-512 RFC is still in draft[1], the latest draft it =
contains a "SHOULD" recommendation of 10000, which was bumped up from =
4096 in an earlier version of the draft:

This is however the draft for a different algorithm: SCRAM-SHA-512.  We =
are
supporting SCRAM-SHA-256 which is defined in RFC7677.  The slightly =
lower
recommendation there makes sense as SHA-512 is more computationally =
expensive
than SHA-256.

It does raise an interesting point though, if we in the future add =
suppprt for
SCRAM-SHA-512 (which seems reasonable to do) it's not good enough to =
have a
single GUC for SCRAM iterations; we'd need to be able to set the =
iteration
count per algorithm. I'll account for that when updating the patch =
downthread.

--
Daniel Gustafsson		https://vmware.com/