Subject: Question about PIM authentication draft (Re: WG Last Call)

From: Thomas Hardjono <[email-masked]>
Date: Thu, 02 Dec 1999 14:13:12 -0500

<bigger>Hi,

I have a question about the PIM control-message authentication

draft.

In the draft, all PIM-routers are assumed to be in possession

of an equal-opportunity-key (symmetric key) which is to be used

for the authentication of control-messages (per hop) between

two PIM-routers using IPsec AH.

Now, since the BSR uses public-key technology (ie. RSA)

to digitally-sign the bootstrap announcements,

this implies that all the PIM-routers must have

public-key crypto capability (in addition to

private-key crypto for IPsec AH).

If this is the case, why not just take the approach

of each PIM-router being given a public-key pair

and a corresponding PK-certificate (signed by a local

or domain-wide Certificate Authority).

Advantages:

This will remove the need of having all PIM-routers

share the same equal-opportunity-key (which may be

considered unwise by some in the security community).

Instead, each pair of router would setup a pair-wise

IPsec Security Association starting with its public-keys.

(The SAs are needed in any case if we are using IPsec).

They would then agree on a unique symmetric-key shared only

between them for control-messages (via IPsec AH).

This would also allow each router to be sure as to

who it is communicating with.

Any comments?

cheers,

thomas

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</bigger>

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Thomas Hardjono

Advanced Network Research

Nortel Networks

[email-masked]