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 2 and 2 of 3 setups, but the most sensible use is likely the 2 of 3 scenario. In that case, two parties must agree on a third, and then enlist that arbitrator to contribute his cryptographic information to theirs. A transaction is constructed including encryption data from all three parties (which remains under their control). This process locks the Bitcoin value that the originating party (typically a buyer) intends to give to the recipient, whether a seller or service provider. Only when the m-of-n threshold has been reached, by sufficient digital signatures being affixed to a new transaction, is the transfer recognised as complete.

In a 2-of-3 transaction, if neither the seller nor buyer can agree and the adjudicator refuses to make a call, the money remains locked away forever. Or if the neutral party and the buyer agree, the money can essentially be refunded to the buyer. The arbitrator only has the power to provide or withhold as digital imprimatur; he cannot abscond with the funds. And his ability to threaten is limited, as the primary participants in the transaction can agree on a resolution without him, should he prove venal or useless.

The social problem of one party corrupting the arbitrator remains possible, but given that both entities in the transaction must agree on which judge to pick, careful selection should avoid such conflicts.

Yet, despite having been technically available for nearly two years, dispute resolution remains in the realm of boffins. Nadav Ivgi of Bitrated hopes to change that. His fee-free website assembles all the technical pieces in such a way that an average Bitcoin user, who has to be relatively conversant in finer details at the moment, should be able to paste in the requisite information. It is the glue, he says, that is currently missing. Therefore Mr Ivgi, based in Israel, is assembling a directory of people willing to offer their services as arbitrators.

Bitrated is designed such that none of the private encryption details (the hidden key portion of the public-private key pair used in Bitcoin transactions) is ever uploaded to his systems. Rather, those involved generate the data necessary and then paste it into various fields. Mr Ivgi, who has developed his software under an open-source license to allow scrutiny, says Bitrated does not even known the identity of a selected arbitrator, or either of the parties.

Mr Ivgi believes that Bitcoin could be much richer in form were dispute resolution to become widely adopted. For his part, he doesn't intend to charge a fee for Bitrated to enable the process, but hopes a rising tide lifts all boats as the foxes cross the river.