[hashcash] Re: outlook 2007 - postmark == hashcash-derivative

Adam Back wrote:

Hi

Someone pointed out to me that outlook 2007 has a feature called a
postmark, which appears to be basically hashcash.  Of course they have
a different header name and use an incompatible format.
amazing. They have probably been paying attention to our work and unfortunately did the Microsoft thing. are you sure enough it's hash cash or just similar to what hash cash does? I wonder if they are basing their stamp on the Penny Black model?
this comes at an interesting time because I've been having some conversations with people on the CRM 114 list about using proof of work to bypass a content filter and with some of the news about the super enormous bot nets, I am starting to have some doubts that we could generate a large enough stamp to consume all of the spammer resources and keep the leak through numbers reasonably small.
I'm currently looking into using another property of proof of work puzzles which is that of a reputation proxy. Combining that with a historically defined reputation of a site, one can use proof of work as a reputation enhancer for good sites (i.e. guaranteeing delivery to inbox) and reduce risk to the super enormous bot net (which will have neutral or bad reputation).
This is a window of opportunity. Even if we cannot find out the format, we can put proof of work puzzles into our mail filters and point to Microsoft saying "see, they're doing it. That confirms it's a good technique but we're open standards." Not that anyone cares half the time but it's a thought. 


--
Speech-recognition in use.  It makes mistakes, I correct some.

Other related posts: