Subject: Re: I-D ACTION:draft-ietf-dnsext-tkey-renewal-mode-01.txt

From: [email-masked] (Randy Hall)
Date: Thu, 16 May 2002 11:22:32 -0400

>         Title           : TKEY Secret Key Renewal Mode
>         Filename        : draft-ietf-dnsext-tkey-renewal-mode-01.txt

> This document defines a new mode in TKEY [RFC2930] and proposes an
> atomic method for changing secret keys used for TSIG [RFC2845]
> periodically. 

The way I've read this, it seems the proposed protocol only applies
to renewing Diffie-Hellman exchanged keys.  Does it make sense to 
make it more generic and extend the mechanism to cover all TKEY modes
of deriving a shared secret (e.g. gss-tsig)?

(In practice, a gss-tsig client should be aware of its key expiry,
but having the client manage this and remembering to delete keys 
before they expire was a less clean mechanism than the one proposed
here (and prevents a stronger security policy on the server); in 
short, implementing gss-tsig key renewal was a bit sloppy.  This 
mechanism may have the potential to be an improvement; I'm not sure, 
but I'm wondering if there was a reason it only seems to apply to DH).

Thx
Randy

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From: Yuji KAMITE <[email-masked]>
Date: Mon, 20 May 2002 18:42:07 +0900

[ post by non-subscriber.  with the massive amount of spam, it is easy to
  miss and therefore delete mis-posts.  so fix subscription addresses! ]

> of deriving a shared secret (e.g. gss-tsig)?

This draft makes use of Diffie-Hellman (DH) for establishing secret,
but it does not mean secret generation's method must be limited
within DH. DH method is only one example for solution, so 
we guess other methods such as resolver assigned keying may be available. 

Should we make this proposal to more general description such that
other secret establishment algorithms are also included?
Or, should we keep going in this approach that applies DH as the
first example?----That is, if necessary, additional draft about
other algorithms should be proposed in the future. We mean we have
submitted and regarded this draft as being in such status.

> but I'm wondering if there was a reason it only seems to apply to DH).

I agree with you in terms of extensibility, but as for GSS-TSIG,
we have not taken it into full consideration yet;

We don't know if Renewal method can be actually used in GSS-TSIG framework.
GSS-TSIG is a way for establishing security context with TKEY --
seems to have different view of managing secrets (on Windows);
and it requires fairly complicated procedures.
So, we think much more investigation and consideration would be needed
especially about applicablity with GSS-TSIG.

Regards,

--Kamite

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Yuji Kamite (E-mail�§[email-masked])
NTT Communications Corporation
         TEL: +81-3-6800-3261 FAX: +81-3-5365-2990