On Fri, 16 Jul 2004, Douglas Otis wrote:
Why not just get the originator's MSA to sign the original return path?
This gives end-to-end authentication of the MSA, does not require any
change to aliasing/forwarding systems or to SMTP, and works well with
callback verification.
Dave Crocker's BTAV draft is a start at a specification.
After reviewing the Bounce Address Tag Validation (BATV) specification
further:
http://www.brandenburg.com/specifications/draft-crocker-marid-batv-00-06dc.html
It seems possible to constrain <original local part+timestamp>/sig-type/sig
where the local part and timestamp as to to validate the message. The
order of these elements could be
<localpart+timestamp>/signature/selector
Have the formats used by SRS and SES been considered here? There are
several arguments about format presented at
http://www.libsrs2.org/srs/srs.pdf.
Primarily, the localpart contains the largest possible character set,
therefore it makes sense to put it last. The first few occurrences of the
separator therefore separate (say) base32 encodings of the various special
fields, and this separator is not a valid base32 character. Any remaining
text is the original local part.
The ability to use a known fixed string followed by a separator character
at the beginning of the address makes it easy to identify mails with
'special' return addresses in the receiving MTA when they bounce.
S.
--
Shevek http://www.anarres.org/
I am the Borg. http://www.gothnicity.org/