Where does money come from? Dollars are printed by the U.S. Mint. For cryptocurrencies, the answer is more complicated. Until now, the digital tokens with the biggest market value, bitcoin and ether, have only been issued to pay for tasks performed by so-called miners in what are known as proof of work systems. It's an approach that has drawn increasing criticism for the large amounts of energy consumed and pollution produced. Around Sept. 15, ethereum, the platform for ether, is switching to a different system, called proof of stake, in a process known as the Merge. Proponents say the approach can cut ethereum's electricity use by 99%.
- What are the 'proof of' systems for?