[hashcash] MTA mints tokens

  • From: Bernhard Kuemel <bernhard@xxxxxxxx>
  • To: hashcash@xxxxxxxxxxxxx
  • Date: Wed, 28 Sep 2005 14:35:11 +0200

Hi hashcash!

If MTAs added tokens to emails this could allow sooner deployment of hashcash while users still use non hashcash MUAs. Small MTAs can take the load while bigger systems may need additional computing resources. A dedicated minter server cost roughly 0.06 cent/minute or 18 minutes/cent. I guess most people would not mind paying 0.06 or even 1 cent per email so this cost can be included in the ISP costs. To avoid spammers abusing this service the number of emails/day can be limited. Heavy email users have to pay extra or make hashcash themselves. Occasionally exceeding the limit may get emails delayed until token computing power get's available at off peak hours. Minting can also be ordered by email priority.

Moving token creation to a permanently online MTA probably also allows for convenient negotiation of required token bits. This could be part of SMTP.

Talking about wasting resources reminds me I'd rather like to pay real money to the receipient than for wasted resources. But anonymous ecash may be difficult in the days of big brother.

Bernhard

[1] A server may cost 50000 cent with a lifetime of 3 years makes 50000/(3*365*24*60)=0.03 cent/minute. Electricity costs: 15 c/kWh / 0.1 kW / 60 minutes/h = 0.025 c/100 W/minute. So we are at 0.06 c/minute or 18 minutes/c. Double/halve that for systems which idle half the time.

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