Hi! I followed the recent discussion about methods to use Hashcash for spam protection. I have to admit that most of those strategies appear to me much too complex to achieve a better acceptance. IMHO in order to raise the approval rate deployment and practical operation have to be less complicated in the first place. Keep it simple! And later on, if it stands the test, add further gadgets or even build a dedicated infrastructure. The presence of a recipient specific token itself already qualifies a message, so that spam recognition systems have to rate it in their evaluation process, considering the value (bits) it represents as well. More bits - better rating. That's why I added a simple Hashcash minter to OmniMix (v0.9.9.2), a Windows based NNTP/SMTP/POP3 proxy server used to anonymize messages by means of onion routers. It now allows to equip all mails, whether sent the normal way or through the remailer network, with tokens based on the recipients' ('To:'/'Cc:') mail addresses ('abc@xxxxxxx'). The size has to be set within the program. To prevent from exaggerated computation times there's an option to reduce it on a message-by-message basis dependent on the number of tokens to be calculated. So even longer mailing lists don't 'cost' more time and shouldn't overload the system. Just my 2 cents of contribution to your project. Kind regards and best wishes for a successful future Christian -- OmniMix .. protect your privacy http://www.danner-net.de/om.htm