I have some thoughts on this issue, but am holding off on commenting
until the charter is settled.
-Jim
On 27 Nov 2024, at 13:30, Bron Gondwana wrote:
I posted an updated draft for this last week with the 'z=y' case for
"complex irreversible change".
I am interested (yes, I know - technical questions before chartered)
in how people feel about a line-based copy format rather than just the
character based one. I'm thinking that because the most common
"corruption" of emails is different line endings; and that will mess
with character counts - and the canonicalisation for calculating body
hashes is designed to give the same result if line endings change.
Bron.
On Mon, Nov 18, 2024, at 09:19, Bron Gondwana wrote:
I don't believe it's that complex, and I do believe it's worth the
effort in exchange for being able to tell with certainty which entity
(by signature; which DNS domain) is responsible for creating each
part of a message. You can then attribute parts of the text to
different entities - the original author, or the mailing list
signature.
And if a message is bad then it's possible to derive where the
badness was introduced - something not possible with DKIM or ARC if a
message has been modified. I have a draft for a method at:
https://datatracker.ietf.org/doc/draft-gondwana-dkim2-modification-alegbra/
It can be used to describe all "add text" cases quite nicely, as well
as wrapped structures where an existing message gets moved into a
multipart/mixed with more content at the end. There's still some
testing to be done for the most complex cases - but this doesn't have
to be a two-way algorithm, is just has to allow describing how to
convert a new email body back to the original email body, and I
believe this can be done reliably and at a reasonable cost, though it
could definitely use some more examples.
I'm going to publish an update with another mechanism which reduces
the cost of the "remove an attachment" version to at least not fill
the headers with tons of junk. It doesn't reduce the message size
though, because you do need to be able to recreate the old message.
And I do agree there needs to be a way to say "I made changes, and
I'm not telling you how to undo them" as well.
Cheers,
Bron.
--
Bron Gondwana, CEO, Fastmail Pty Ltd
[email protected]
--
Bron Gondwana, CEO, Fastmail Pty Ltd
[email protected]
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