“Lead Bitcoin developer Gavin Andresen is skeptical, saying that even if the potential attack described in the paper works, its claim that it could ultimately fundamentally break the currency is based on a series of bad assumptions. ‘I’m not convinced it’s correct and I don’t think it’s been peer-reviewed,’ said Andresen by phone from Australia. Andresen, who had read the 17-page research paper about a problem in Bitcoin’s core protocol that would allow selfish miners to build longer branches on the blockchain secretly and cut other honest ‘miners’ out from getting Bitcoins for their work, did not have an immediate pronouncement on whether the vulnerability exists or not.”
http://www.forbes.com/sites/kashmirhill/2013/11/06/bitcoin-is-not-broken/