The largest group of bitcoin miners, which maintains and processes transactions in the digital currency, is promising to avoid majority control of the currency as a temporary measure to maintain the payment system's credibility.

Mining pool GHash.IO, which is controlled by a British company, CEX.IO Ltd., said Tuesday that it would not amass more than 40 percent of the of the bitcoin system. Earlier this summer, it briefly exceeded 50 percent.

Miners operate the computers that keep track of bitcoin transactions. As a reward, they receive newly minted coins. A miner that controls more than 50 percent of bitcoin processing could control the flow of transactions, freeze people out of the network and keep all future bitcoins for itself.