Subject: SHA-2 based HMAC algorithm...

From: Joseph Galbraith <[email-masked]>
Date: Fri, 18 Mar 2011 17:17:36 -0600

Is there a SHA-2 based HMAC algorithm specified in any of
the recent extension RFCs?

I looked but didn't see one.

Has anyone implement such a thing as a @domain.name extension?

Thanks,

Joseph

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From: "Mark D. Baushke" <[email-masked]>
Date: Fri, 18 Mar 2011 21:52:04 -0700

Hi Joseph,

> the recent extension RFCs?

Given you are asking in ietf-ssh, I suppose you are interested in just
the secure shell protocol? If so, the place to look toward the IANA
assigned names for the SSHv2 protocol at the
http://www.iana.org/assignments/ssh-parameters URL.

> I looked but didn't see one.

I concur, there is nothing regarding the use of HMAC-SHA-2* algorithms
with the secure shell protocol currently listed published in an RFC.

If you are interested in SHA-2 based HMAC algorithms listed in the RFCs
in general, then there are some recent works which have such references:

RFC 5709 (OSPFv2 HMAC-SHA Cryptographic Authentication) which references
         HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512 and has a MUST for
         HMAC-SHA-256 support.

RFC 4868 (Using HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512 with IPsec)
         which talks about using them as PRFs for IKE and IKEv2.

> Has anyone implement such a thing as a @domain.name extension?

For the secure shell protocol, I have seen these macs:

  [email-masked]
  [email-masked]
  [email-masked]
  [email-masked]
  [email-masked]
  [email-masked]

being negotiated, but there may be other folks who are adding their own
extension too.

        -- Mark

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From: Peter Gutmann <[email-masked]>
Date: Sat, 19 Mar 2011 18:28:47 +1300

>For the secure shell protocol, I have seen these macs:
               ^
I've heard of two-bit security mechanisms, but I've never seen one used in an
actual protocol before.

>but there may be other folks who are adding their own extension too.

Give that SHA-2 is becoming more widespread, perhaps we need a quick RFC, or
at least an ad-hoc implementers agreement, on naming for this before we get
dozens of [email-masked] extensions.

Peter.