Subject: Re: [karp] Using dynamically derived Traffic Keys for Routing Protocols

From: Sam Hartman <[email-masked]>
Date: Wed, 04 May 2011 11:57:27 -0400

A couple of points.

First, I don't believe key derivation helps protect against a situation
where the long-term key is compromised.
There are cases where key derivation minimizes the use of long-term
keys, and there are some cases where that can reduce the chance of
compromise.

>>>>> "Joe" == Joe Touch <[email-masked]> writes:

    Joe> Hi, all, I'm wondering whether the KARP docs talk about the
    Joe> assumptions behind short-term keys, notably that any long-term
    Joe> session is either restarted or can support rekeying.

    Joe> This isn't an issue for TCP-AO, but there are other protocols
    Joe> (legacy TCP MD5, and SSH which is being advocated for use for
    Joe> route caches in the new SIDR docs) that may not be as friendly
    Joe> to short-lived keys.

    Joe> FWIW.

I think there is a requirement that what we recommend in KARP support
changing the session key without breaking routing adjacencies. You can
do that either by having a way to replace a transport connection or
having a way to replace the tkey within a session.

Note that SSH definitely does support replacing the key of an existing
session; key exchange can be re-executed.