Email privacy and spam are such general problems today that I'd
like to ask the ietf-org list for feedback (private if you wish)
on this suggestion. There are more specific forums where this
can (and shall) be discussed.
1. I make my public-key available wherever my email address is given;
2. Except for senders in a whitelist (e.g., list mail), I bounce to the sender
any email that is NOT encrypted with my public-key, providing my
public-key and instructions for the sender to resubmit the message
This would make spammers pay FOR EACH message sent, as messages
would need to be encrypted FOR EACH recipient. At the same time, it
would promote email privacy protection en route, including at ISPs
and before mail pickup at POP boxes.
The end points would not be authenticated at this time, making it much
simpler to implement. Sender authentication is also not effective as a
burden mechanism for each message.
The built-in spam burden & email privacy protection afforded by this
procedure would not be costly to use as there are several free tools
available for encryption. The whitelist should provide a backward path
for those who don't want or can't use encryption at this time.