And what happens when there's a network outage and a message gets stuck in the queue for a day on another server? You know a backup MX server when yours is hosed? Do you not accept the mail because the current day doesn't match what's in the message? Or do you accept mails from a day ago? a week ago? a year ago? 1922? 2nd, why wouldn't the spammer just adjust and send an email to each recipient with a random, but properly hashed token to match the target address + today's date? More work for sure, but if enough targets start adopting it, the spammer will adapt. The token doesn't have to contain an actual valid coin, and you'll only find out when you try to cash it. ----------------------Kaos-Keraunos-Kybernetos--------------------------- + ^ + :25Kliters anthrax, 38K liters botulinum toxin, 500 tons of /|\ \|/ :sarin, mustard and VX gas, mobile bio-weapons labs, nukular /\|/\ <--*-->:weapons.. Reasons for war on Iraq - GWB 2003-01-28 speech. \/|\/ /|\ :Found to date: 0. Cost of war: $800,000,000,000 USD. \|/ + v + : The look on Sadam's face - priceless! --------_sunder_@_sunder_._net_------- http://www.sunder.net ------------ On Wed, 14 May 2003, Adam Back wrote:
Well there are different things you could hash. This simplest is just to hash the recipient address and the current time (to a day resolution).
The recipient looks at the token and knows it is addressed to him because it's his address. He stores it in his double spend database and won't accept the same token twice.
After the validity period of a token has expired he can remove it from his double-psend database to avoid the database growing indefinately. (He can reject out-of-date mail based purely on it's date).
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