Cryptocurrencies have exploded in 2017. But while prices are surging, transactions are facing long delays because the networks are flooded with traffic. This is the problem facing the Ethereum network, which, along with its digital currency ether, has quickly become the world's No. 2 cryptocurrency after Bitcoin. And one man, Vlad Zamfir, has a plan to fix it. This week, Bloomberg's Matthew Leising and Brad Stone speak to Zamfir about his big dreams for Ethereum and how his project (codenamed Casper) could pave the way for masses of ordinary internet users to join in the craze.