Re: [DNSOP] RFC 2845bis and HMAC-MD5

Matthew Pounsett <matt@conundrum.com> Thu, 14 March 2019 18:56 UTC

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From: Matthew Pounsett <matt@conundrum.com>
Date: Thu, 14 Mar 2019 14:56:29 -0400
Message-ID: <CAAiTEH80z9B7xcpmppJ=QJ6NQUwROXBMdJDwfLmczw3+EfCiCw@mail.gmail.com>
To: Tony Finch <dot@dotat.at>
Cc: Martin Hoffmann <martin@opennetlabs.com>, dnsop <dnsop@ietf.org>
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Subject: Re: [DNSOP] RFC 2845bis and HMAC-MD5
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On Thu, 14 Mar 2019 at 11:08, Tony Finch <dot@dotat.at>; wrote:

> Martin Hoffmann <martin@opennetlabs.com>; wrote:
> >
> > As such, I would like to propose to move HMAC-MD5 to optional and only
> > retain SHA-1 and SHA-256 as mandatory.
>
> That seems sensible. There should at the very least be a reference to
> RFC6151, Updated Security Considerations for the MD5 Message-Digest and
> the HMAC-MD5 Algorithms.
>

Agreed.  I can't remember the last time I generated an HMAC-MD5 key .. and
I believe the default behaviour for most (all?) recent major distributions
default to something stronger (e.g. BIND now defaults to HMAC-SHA256).  Any
operators needing to support old key algorithms would be free to use
distributions that continue to optionally support them, or generate and
distribute new keys (something that should be done periodically anyway).