Hashcash Mint

A chrome extension that lets one create (or 'mint') Hashcash email stamps. Mint a stamp, then simply cut and paste it into your outgoing email. A little popup has fields to enter the To: address and the strength in bits of the hashcash stamp to generate. The stamp is generated in the background and you can go on browsing while it works.

If you use gmail, you can install the corresponding Chrome app, "Hashcash for Gmail", which can scan your inbox and prioritize, star, filter or flag incoming email with (or without) valid Hashcash stamps automatically!

Hashcash is a proof-of-work algorithm that generates partial SHA1 hash collisions in order to make a stamp that is hard to generate, but easy to verify. Recipients of your email can prioritize emails from you if you send a valid Hashcash stamp in the email body. Fore more information see http://www.hashcash.org/

NOTE: To enable this extension to reside in a panel at the bottom of your browser rather than in a separate window, invoke Chrome with the --enable-panels option. This may or may not be required for Chromium.