James Delahunty
5 Nov 2013 13:02
A group of researchers are Cornell University have warned that the Bitcoin system is vulnerable to an attack that could allow a group to gradually take control over it.
The flaw, they allege, involves the process by which new Bitcoin is created. Bitcoins are mined by groups of computers working on a cryptographic problem, and at any given moment thousands of machines and many groups can be working to solve the same puzzle.
Here is where the Cornell researchers find the potential weakness. If one large mining group could game the system to keep the discovery of blocks quiet, then other groups may continue to mine to no avail while they move on. Hence, why it is described as a "selfish" attack.
"Once the system veers away from the happy mode where everyone is honest, there is no force that opposes the growth of really large pools that command control of the currency," wrote Professor Emin Surer.
You can read a more detailed description of the attack from Professor Surer on his blog post titled "Bitcoin is Broken".
Vitalik Buterin, technical editor of Bitcoin Magazine, is sceptical that such an attack would work in practice, because it would require that attackers change fundamental BitCoin software to manipulate the information sharing with the network.