Avi Kaner, a co-owner of the Morton Williams supermarket chain in New York, has spent about $700,000 to update the payment terminals at his stores. Trouble is, he cannot turn them on. The new terminals can accept credit and debit cards with embedded digital chips, a security feature intended to reduce the number of fraudulent purchases. But before the payment systems can work, they must be certified, a process that Mr. Kaner and many retailers around the country are waiting to happen. In the case of Morton Williams, the holdup has lasted several months.