Subject: [Openpgp-dt] A (very late, sorry) proposal to change the v5 SKESK packet

From: Justus Winter <[email-masked]>
Date: Thu, 03 Mar 2022 15:57:03 +0100

Hello,

I just filed a proposal to change the SKESK v5 packet ever so slightly,
by adding a length for the S2K method.  I'm so annoyed at myself for not
noticing that earlier, but this is important to me, so I want to see
whether we can quickly agree or not, and if not, then I'm happily
retracting the proposal.

Please have a look: https://gitlab.com/openpgp-wg/rfc4880bis/-/merge_requests/149

Thanks,
Justus

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From: Justus Winter <[email-masked]>
Date: Fri, 04 Mar 2022 12:12:29 +0100

> whether we can quickly agree or not, and if not, then I'm happily

Daniel and I worked on the change yesterday and are now happy with the
result.  It is a syntactical change to the v5 SKESK packet and v5
encrypted key packets that enables more robust parsing of those packets
even if either the S2K mechanism or AEAD mode is not implemented or
understood by the consuming implementation.  It is our hope that this
makes implementations more robust in the face of as-of-yet undefined
data, i.e. forward compatibility.

This is analogous to how we now can robustly compute the v5 public key
packet from a v5 secret key packet even if we don't understand the
public key algorithm used, because v5 added an explicit octet count for
the public key material.

Because I haven't heard any negative feedback, I'm optimistically
assuming that we can get this change in and will now start to produce
test vectors using this.

Nevertheless, please have another look:

  https://gitlab.com/openpgp-wg/rfc4880bis/-/merge_requests/149

Thanks,
Justus