In Sneakers (1992), the device that can decode any encryption is called the black box.
The black box is the central technological prize in the film. Mathematician Cosmo tells Martin Bishop’s security team that the device was created by mathematician Gunter Janek and can defeat virtually any computer-security system. Its importance makes it valuable to both government agencies and criminal interests.
The film uses the black box to turn a technical idea into a suspense device. Rather than focusing on one particular password or computer, the story imagines a universal decryption machine that would make secure communications impossible. This is why the team is pursued after recovering it.
A common mix-up is confusing the black box with the phrase “Setec Astronomy,” the fictional company that hires Bishop’s team. Setec Astronomy is the client; the black box is the decryption device. Sneakers was directed by Phil Alden Robinson and released in 1992.