RE: namedroppers, continued

On Fri, 6 Dec 2002, Ayyasamy, Senthilkumar    wrote:

> If the proof of effort requires, say, 10 seconds to compute, then the
> economics of sending spam are radically altered, as a single machine
> can send only 8,000 messages per day.
Wouldn't something like this cause problems for (large/free) email
providers?  They would probably need a lot of extra hardware to do all
this computation. And until something like this is included in the
standard, the receiver must accept mail from senders that don't implement
this yet.

I personally like the idea behind qconfirm (http://smarden.org/qconfirm/)
and TMDA (http://tmda.net/). If I receive an email that I do not recognize
or otherwise find to be authentic, a mail is sent back to the sender,
requesting that they send a verification mail to a unique secret address.
When a mail is received at this secret address, the original mail is
delivered to me, and the secret address is removed. For a spammer, it is
too expensive to receive and reply to all these mails.

Ketil