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Fraud and spam are two separate problems. One of the best solutions for spam for a new system is to impose a proof of work requirement on sending the first mes
by zrm 7y ago
Fraud and spam are two separate problems.
One of the best solutions for spam for a new system is to impose a proof of work requirement on sending the first message between any pair of users, or any (new username, hosting service) pairing for federated services. For any normal pairing that happens only once, but for a spammer they have to pay the cost for every message or else you can trivially block every message from that sender.
Fraud protection is harder, but it's also something that lends itself well to being an independent service. If you're buying from someone trustworthy or dealing in small value amounts then you don't need it. If you're not, you require the seller to carry insurance from someone you do trust (or don't buy from them), and then it's the insurer's problem to deal with fraud.
- Jasper_ 7y agoSpammers have large networks of computers they aren't paying for (botnets), so they aren't paying the cost of sending messages. Proof of work really doesn't solve spam anymore.
- zrm 7y agoWhat makes it work is the asymmetry. With normal human communication you talk to the same person thousands of times, or send thousands of messages from the same account, so spending computation equivalent to something like $1 worth of Bitcoin for that is totally reasonable. Spending the equivalent of $1 worth of Bitcoin to send one spam to one person, isn't. Even if you had access to a large number of computers, you'd make much more money by using the same computational resources to mine cryptocurrency. The opportunity cost makes spamming uneconomical, and if it doesn't then you raise the cost until it is. You can also allow users to pre-approve each other to avoid paying anything so that most legitimate communication doesn't require proof of work, which makes it a lot easier to put a high price on the remaining instances.