Sneakers - Phil Alden Robinson

Martin Bishop is the head of a group of experts who specialise in testing security systems. When he is blackmailed by Government agents into stealing a top secret black box, the team find themselves embroiled in a game of danger and intrigue. After they recover the box, they discover that it has the capability to decode all existing encryption systems around the world, and that the agents who hired them didn't work for the Government after all...