The sad thing is that a solution for protection against spam has existed for about thirty years, yet it is almost unused. It is based on the same idea that late

The sad thing is that a solution for protection against spam has existed for about thirty years, yet it is almost unused. It is based on the same idea that later came to underpin Bitcoin: proof of work: https://news.ycombinator.com/item?id=30220979 https://news.ycombinator.com/item?id=30220979