In Sweden, the number of banknotes and coins in circulation has fallen to its lowest level in three decades. Riksbank estimates that cash transactions made up only 15 percent of all retail transactions last year. That number is down from 40 percent in 2010, thanks in large part to massively popular mobile payment services. That leaves the bank wondering if a technology similar to that of Bitcoin's could be implemented in Sweden.

Riksbank isn't the only central bank taking a serious look at blockchain, the technology that makes Bitcoin and other cryptocurrencies run. These systems, also called distributed ledgers, rely on networks of computers, rather than a central authority like a bank, to verify and record transactions on a shared, virtually incorruptible database. Government bankers across the world believe this has the potential to replace cash and make other payment systems more efficient. – Technology Review