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Re: Human I&A, IPsec, and their non-relationship
Phil, you are right: the key is doing frequent, efficient updates of
the `session keys'. Your suggestion below is essentially identical to
what we proposed (in MKMP); you need to deal with the protocol to do this
to avoid replay, loss of sync etc, which is exactly the MKMP protocol.
> The session key will probably be generated along the lines of
>
> key = MD5(DH shared secret, cookie1, cookie2, SAID)
>
> where cookie1 and cookie2 are the Photuris cookies in sort order.
>
> This clearly makes session key establishment cheap enough to permit
> frequent session rekeying. E.g., each SAID could be given an
> administrative lifetime in seconds and/or packets, after which a new
> one is created with a new key, the old one is destroyed, and traffic
> rerouted to use the new SAID.
I suggest we make sure that at least this component of deriving session keys
from master keys is one and common across all implementations. Furthermore
I agree with you that we can have a single protocol which is tunable to meet
different security/efficiency tradeoffs... I'll like to have more technical
discussion about this protocol to achieve all our goals. More on this later.
Best, Amir
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