If cryptocurrencies are dangerous because of their proliferation among criminals, central banks are keen to make sure the same can’t be said of their own digital currency projects.

Proposals for a digital version of sterling and other fiat currencies are gaining traction — with some projects more advanced than others — as central banks race to head off competition from private cryptocurrencies such as bitcoin. Most plans include some form of identity verification, a way of making sure the person spending the digital currency is who they say they are and tracking what they buy.