[hashcash] instead of DNS, stamp value server
- From: "Eric S. Johansson" <esj@xxxxxxxxxx>
- To: hashcash@xxxxxxxxxxxxx
- Date: Tue, 18 Jul 2006 10:56:12 -0400
this occurred to me quite a long time ago but I never wrote it down.
If instead of using DNS, we used a simple server (Web, XML RPC) and the
request returned the number of bits of stamp that IP address should
calculate in order to successfully pass the filter on the far side.
This bit server would also be a reputation server. the number of bits
it would return for an IP address would increase if spam came from that
IP address and it would decrease if mostly good e-mail came from the IP
address.
For example, if you get e-mail from an ISP and the first 10 messages
come in with stamps and are not declared spam, the requirement for that
ISP would drop by a bit. If another 10 messages come in, the
requirement drops by another bit until the maximum reduction in stamp
size has been reached.
On the other hand, an IP address start sending you spam and after 3
messages, you increase the required spam by a bit so forth and so on
until they are looking at the maximum increase in stamp size.
What's interesting about this is that if you have a company sending out
newsletters and the newsletters are voted as spam, their stamp
requirements are now significantly increased which tells them that the
reputation is in the dumpster.
this is what I call stamp size as a proxy for reputation. Stamps can
also be used as a proxy for attention in a similar way. make a big
enough stamp, you get through.
the same database that is used for the reputation proxy can also be used
for a blacklist in that if the message has a bigger than average stamp
size, it's not let through unless it has a stamp of that size.
stamps are fun to play with.
---eric
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