Re: Why are mail servers not also key servers?

Wei Chuang <weihaw@google.com> Fri, 21 April 2017 17:00 UTC

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References: <FC831208-97A3-4F1B-A37C-F8646C3FB208@gmail.com> <20170420205434.24400.qmail@ary.lan>
From: Wei Chuang <weihaw@google.com>
Date: Fri, 21 Apr 2017 10:00:22 -0700
Message-ID: <CAAFsWK1FtqM2GqTkCWzgm-L87KoXGFW+yorRF-t===MycjR1Ow@mail.gmail.com>
Subject: Re: Why are mail servers not also key servers?
To: John Levine <johnl@taugh.com>
Cc: "ietf@ietf.org" <ietf@ietf.org>
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I just wanted to second the draft-bhjl-x509-srv approach as preferable as
opposed to a new SMTP extension.  That draft calls for transport of the
certificate request and response to be over HTTPS.  As HTTPS is based on
Web PKI and generally has more up-to-date crypto (due to the ecosystem)
that traffic will stay private.  SMTP uses STARTTLS which has stripping
problems, and its PKI is worse off.  There's a lot of self signed certs
there making certificate path validation problematic.  Just my two cents.

-Wei

On Thu, Apr 20, 2017 at 1:54 PM, John Levine <johnl@taugh.com> wrote:

> In article <FC831208-97A3-4F1B-A37C-F8646C3FB208@gmail.com> you write:
> >> SMTP servers could be key servers without having the private key of
> >> individuals?
> >
> >Sure. If they double as HTTPS servers.
>
> As others have noted, this topic has come up more than a few times before.
>
> Here's a recent draft we wrote for a simple per domain https key
> server, based almost entirely on existing standards.  It distributes
> public keys.  Managing your private keys on all of your MUAs remains
> as intractable a problem as it's always been.
>
> https://datatracker.ietf.org/doc/draft-bhjl-x509-srv/
>
> R's,
> John
>
>