Subject: [IPsec] Can selected IPv6 Headers be part of Authenticated Data with ESP-GCM?

From: Robert Moskowitz <[email-masked]>
Date: Mon, 25 May 2020 10:08:17 -0400

I have an interesting use case for a new IPv6 header that MAY be secure 
within the ESP payload, or MAY be exposed for inroute processing, but 
MUST be protected (authenticated data).

My cursory review is not showing this is currently supported.

Is it, our would I need to define a variant of the AES-GCM mode?

Thanks

---

From: Michael Richardson <[email-masked]>
Date: Mon, 25 May 2020 12:47:37 -0400

Robert Moskowitz <[email-masked]> wrote:
    > within the ESP payload, or MAY be exposed for inroute processing, but MUST be
    > protected (authenticated data).

That's not the ESP model.
ESP only protects something inside/after it.
AH did what you wanted. Sorta.

I suggest you put two copies of the header, or you make one copy an implicit
property of the SA (a la BEET mode) if need the packets to "emerge" with that
header and you don't want to spend bytes.  It's obviously mutable in-transit.

I don't think it matters what cipher you use, although I can imagine trying
to bork this issue via some super-specific custom thing.

--
Michael Richardson <[email-masked]>, Sandelman Software Works
 -= IPv6 IoT consulting =-