Bitcoin’s baby: Blockchain’s ‘tamper-proof’ revolution – BBC News, 20 May 2015

But when it comes to putting all this into practice, one Harvard internet law professor thinks he has spotted a flaw. “Why would we assume that now and forever no one entity could command more than half of the computing power of the people mining a Blockchain?” asks Prof Jonathan Zittrain. “I haven’t really heard a satisfying answer to that.”

Source: Bitcoin’s baby: Blockchain’s ‘tamper-proof’ revolution – BBC News