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Cost-based Anti-spam Systems
Since spam occurs primarily because it is so cheap to send, a proposed set of solutions require that senders pay some cost in order to send spam, making it prohibitively expensive for spammers. Stamps Some gatekeeper would sell electronic stamps and keep the proceeds. Or a micropayment, such as electronic money would be paid by the sender to the recipient or their ISP, or some other gatekeeper. Proof-of-work systems Proof-of-work systems such as hashcash and Penny Black require that a sender pay a computational cost by performing a calculation that the receiver can later verify. Verification must be much faster than performing the calculation, so that the computation slows down a sender but does not significantly impact a receiver. The point is to slow down machines that send most of spam—often millions and millions of them. While every user that wants to send email to a moderate number of recipients suffers just a few seconds' delay, sending millions of emails woul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micropayment
A micropayment is a financial transaction involving a very small sum of money and usually one that occurs online. A number of micropayment systems were proposed and developed in the mid-to-late 1990s, all of which were ultimately unsuccessful. A second generation of micropayment systems emerged in the 2010s. While micropayments were originally envisioned to involve very small sums of money, practical systems to allow transactions of less than 1 have seen little success. One problem that has prevented the emergence of micropayment systems is a need to keep costs for individual transactions low, which is impractical when transacting such small sums even if the transaction fee is just a few cents. Definition There are a number of different definitions of what constitutes a micropayment. PayPal defines a micropayment as a transaction of less than £5 while Visa defines it as a transaction under 20 Australian dollars. History The term was coined by Ted Nelson, long before the inventi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |