Peter J. Holzer wrote:
But let's assume we charge 1c/10k messages/day. [...] And even if a
bot occassionally exceeds that limit, how many users will even
notice if their ISP charges them a few cents more per month, much
less clean up their PC?
Hm... that assumes that ESPs will buy tokens (or stamps) on behalf of
the message authors. Postage systems, with the exception of some
hotels and similarly managed residential arrangements, require that
authors go to the post office to buy stamps. Deciding _who_ affixes
the tokens is required for a protocol that is agnostic about what the
tokens contain; e.g., on-the-fly negotiation does not suit the stamp
metaphor if acquiring tokens involves interacting with the authors.
If tokens are affixed by the transport system, a submission agent is
implied. That prevents authors from sending via occasional servers
(much like SPF and DKIM.) It is this fully automatic acquisition and
affix that calls for a venial content of the tokens.
If tokens are affixed by authors, they must be able to acquire them
through firewalls, hence via http[s]. Is it possible to send a token
for the reply as an attachment? How do I know what tokens I've already
used? Then I should also ask what difference does it make if an
incoming message has a token affixed. Possibly, affixing a token as an
attachment rather than a header would make it more visible to the
recipients, while machine readable parts can live both in the
attachment's headers and in exif-like encoded data. (And yes, IMHO
S/MIME signatures are not used because they are rendered so poorly.)
_______________________________________________
Asrg mailing list
Asrg(_at_)irtf(_dot_)org
https://www.irtf.org/mailman/listinfo/asrg