Also see A surge in the value of crypto-currencies provokes alarm (The Economist)
"The price of Bitcoin, a digital currency once located at the fringe of finance, has been rising to new records in recent months as digital assets move into the mainstream.It's not just Bitcoin anymore... - BBC News
On Tuesday, it shot past $2,200 (£1,700), more than doubling from just two months ago. And a newer currency, Ethereum, has climbed even faster.
Industry members say uncertainty surrounding the value of global currencies, including the pound, is driving demand for alternative currencies."