I still recall what Nobel Laureate Yunus told Harsha de Silva during a television interview: the mobile was going to the new Aladdin’s Lamp, giving its user not one thing, but many. I don’t think he meant it would open doors, but that’s what this story documents: Front pockets and purses are slowly being emptied of one of civilization’s most basic and enduring tools: the key. It’s being swallowed by the cellphone. New technology lets smartphones unlock hotel, office and house doors and open garages and even car doors. It’s a not-too-distant cousin of the technology that allows key fobs to remotely unlock automobiles or key cards to be waved beside electronic pads at office entrances.