That sounds like a quite portable way to do this, should work for many unix mailers. I'd be interested to try using it myself. My only complication is I am using mutt on a machine where I am not root, and also I am not sure how long a process left running (the daemon) would last by itself. Well in my case so far I was thinking of generating smaller stamps (eg 20 bits), so probably that wouldn't matter too much. And I guess the daemon just leaves things in the queue if it hasn't processed them fully. Please send the code! Can you put it on the web? (eg. As alpha/beta if you're still changing it). Adam Kyle Hasselbacher wrote: > I wrote a stand-in for sendmail that I can call from Mutt to add hashcash > to my outgoing mail. It does a bit more than just that, though. > > The computer I use for email is a modest 400MHz. Computing 26 bits of > hashcash (my chosen default) takes nearly ten minutes. > > Given that, my filter is actually two programs. One acts like sendmail for > Mutt and merely writes Mutt's message to a queue. The other program is a > daemon that watches that queue and does the work of adding hashcash before > sending it to the real sendmail.