[cap-talk] can one use capabilities to stop spam without identity?

[Matej Kosik]

Friends,

John Carlson wrote:
> Capabilities use introduction to get two parties communicating.  This  
> effectively stops spam.

I like to say: "capability/ies is a mechanism for enforcing arbitrary
descriptable security policy.

If there is some public entry point to your mailbox (because you cannot
know in advance who would want to send you useful information) then the
your security policy: "I do not want spam" is not descriptable (there is
no system which would be able to crisply discriminate "good" from "bad"
mails.

Here
http://www.amazon.co.uk/Earthweb-Marc-Stiegler/dp/067157809X/sr=8-1/qid=1169324664/ref=sr_1_1/203-8113942-1334354?ie=UTF8&s=books
page 173, bottom half of the page

is (I believe) the only reasonable solution that might work. It is
possible to enforce such an security policy where you charge senders for
sending you a mail certain amount of money. You then review/read your
mails and money connected with non-spam-mail is returned back to the
senders. This of course does not prevent unsolicited mail (because you
do not want to prevent it) but you are compensated with appropriate
amount of money. How much you will charge for a mail (you might even
discriminate among people you already know) is up to you.

Such security policy, I believe, is descriptable and quite simple.

What do you think? Or, at least I would like to know why the above
approach would not be effective.

> But how can two parties who don't currently  
> communicate with each other start communicating?

[snip]

Regards
-- 
Matej Kosik

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