[Cryptography] Good private email

[Jerry Leichter]

On Aug 26, 2013, at 1:16 PM, Ray Dillinger <bear at sonic.net> wrote:
Minor point in an otherwise interesting message:
> Even a tiny one-percent-of-a-penny payment
> that is negligible between established correspondents or even on most email
> lists would break a spammer.  Also, you can set your client to automatically
> return the payment (when you read a message and don't mark it as spam) or
> just leave it as a balance that you'll return when you reply.
This (and variants, like a direct proof-of-work requirement) has been proposed time and again in the past.  It's never worked, and it can't work, because the spammers don't use their own identities or infrastructure - they use botnets.  They don't care what it costs (in work or dollars or Bitcoins) to send their message, because they aren't going to pay it - the machine they've taken over is going to pay.

Granted, today most machines don't provide access to Bitcoins.  But assuming your idea catches on, they will.  Once a box has a legitimate capability to send some form of mail, it can be subverted to send mail of that form that the owner of that box didn't intend.  As long as endpoints can be "pwned", nothing about those endpoints can be trusted....
                                                        -- Jerry