Vulnerabilitiy in Bitcoin could allow 'any group to take over' - Reap your profits now 11/08/2013 - 00:00 The digital currency Bitcoin is one of the zeitgeist phenomena of our time. Since 2009, it has grown from a digital curiosity to an online phenomenon. There are now some 11.5 million Bitcoins in circulation and each one is worth over $300.The Bitcoin system is specifically designed to overcome one of the serious flaws of previous digital currencies—the possibility of double spending; that two people could spend two copies of the same currency at the same time. It is also decentralised so that no single organisation or organised group of individuals can control the currency and prevent certain types of transactions.