The Economist, 2/19/2014 4:16 AM PST BITCOIN, the volatile virtual currency, is often promoted specifically for its irreversible transactions. There are no chargebacks—a term from the credit card world in which a merchant's payment is clawed back by a payment network when a purchaser squawks. A transfer of value from one Bitcoin "address," the equivalent of a bundle of currency, to another is sealed for good by cryptographic wax signet rings once the transaction data corresponding to the transfer are added to the global public record.But that's not quite accurate, as many Bitcoin aficionados like to point out. Layered within the Bitcoin protocol since 2012 is a dispute-resolution system that allows two parties to anoint a third to act as a modern Solomon, called upon in need. Knowing that a mechanism exists for reversing problematic purchases could make many more users comfortable with the virtual currency.Bitcoin's approach relies on an "m of n" system, in which, with a total of n parties, at least m of those parties must agree on an outcome. The situation is similar to escrow but without the arbitrator either having control of the funds or being able to access them. It is more like a river-crossing problem: given a supply of chickens, three foxes and a boat, how does one cross without one fox devouring all the birds and leaving his fellows stranded?Bitcoin's current implementation allows for 1 of 3, 2 of ... |