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]
_______________________________________________ Ietf-dkim mailing list -- [email protected] To unsubscribe send an email to [email protected]
