[hashcash] Re: hashcash stamp server

Kyle Hasselbacher wrote:
> [...] I'd like to be able to tell it to generate tokens that expire in the 
> future,
> but that's not written yet. 

Note the current hashcash client rejects stamps with creation dates in
the future.  (Well actually by default it allows 2 days into the future
but that's to allow for a bit of clock / date error).  Argument is to
avoid people filling up your double-spend db with stamps which won't
expire anytime soon because their "creation dates" are far into the future.

ie You could generate them with dates in the future but you should not
use them when that date is still in the future.  As it's hard to predict
when the stamp will be needed, but I presume more likely now than later
it's probably safer to create stamps with the current time as the
creation date.  There is a default 28 day delivery allowance so even if
the stamp is not used for a few days, it should be relatively safe.

> The daemon treats these requests as second class citizens, processing them
> dead last regardless of expense and such.  A finished token is written to a
> file in a directory full of premade tokens.
> 
> When I go to generate a token, I first look to see if there's one already
> available at or above the postage required.  I also check to see if there's
> one already being generated with the same specs I need.  If there's one in
> process, I take over that process.  Taking over another process generally
> only happens with a message displacing a request, but it's possible for one
> message to oust another.
> 
> Oddities:
> 
> * If I have an expensive pre-made token, it gets processed late even though
>   it's really cheap.  I don't notice how cheap it is until the last minute.
>   This means I could have messages that I can delivery immediately hanging
>   around waiting for a message that I wasn't prepared for.

could you get around this issue by checking whether pre-made stamps
exist before generating stamps on demand?  Hmm but that's what you said
above "When I go to generate a token, I first look to see if there's one
already available at or above the postage required." so perhaps I am not
understanding this scenario.

Adam

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