Re: [DNSOP] Time to update RSAMD5 and perhaps DSA (algs 1 and 3) to MUST NOT?

Paul Wouters <paul@nohats.ca> Sat, 01 December 2018 22:32 UTC

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Date: Sat, 1 Dec 2018 17:32:21 -0500 (EST)
From: Paul Wouters <paul@nohats.ca>
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Subject: Re: [DNSOP] Time to update RSAMD5 and perhaps DSA (algs 1 and 3) to MUST NOT?
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On Sat, 1 Dec 2018, Viktor Dukhovni wrote:

> The IANA DNSSEC parameter registry lists RSAMD5 (algorithm 1) as
> deprecated, and refers to [RFC3110], [RFC4034] which state that
> RSAMD5 is "NOT RECOMMENDED".
>
>    https://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml#dns-sec-alg-numbers-1

And our draft is going further and says you MUST NOT implement it :)

https://tools.ietf.org/html/draft-ietf-dnsop-algorithm-update-04#section-3.1

> This suggests to me that the deprecation of RSAMD5 is a stunning
> success, it is gone, and perhaps it is time to say so:

I think more that it never really saw any deployment, so it seems a
little weird to claim success here. It shouldn't ever have gotten
an allocation even back then :P

>    * Authoritative zones SHOULD NOT publish RSAMD5 DS RRs or
>      DNSKEY records.
>
>    * Validating resolvers MUST ignore RSAMD5 DS RRs and DNSKEY
>      RRs, and MUST treat any zones with only ignored or unsupported
>      DS records as "insecure".

How weak. We went for MUST NOT :)

> Perhaps we could be bolder and say the same for DSA (algorithm 3),

Funny, we also have MUST NOT there :)

> this too is largely gone, but there's a cluster of ~4700 ".me"
> domains with DSA keys.  It is not clear that enabling those domains
> to validate merits ongoing support for algorithm 3.  So we might
> also add DSA to the list, encouraging resolver implementations to
> drop support for both RSAMD5 and DSA.

Done, as soon as the document gets a write up and goes into IETF LC :)

ping chairs :)

Paul