Alan Turing’s lesser-known wartime invention, a portable voice encryption device codenamed Delilah, is finally receiving recognition following the discovery of detailed technical notes kept by engineer Donald Bayley.

Key Points

• Alan Turing developed the Delilah encryption system alongside his famous work breaking the Nazi Enigma machine.
• The device was designed as a portable, battery-powered alternative to the massive, room-sized SIGSALY system used by Bell Labs.
• Delilah consisted of three small units weighing approximately 39 kilograms, representing a significant feat of wartime miniaturization.
• The project was never deployed because the need for secure vocal encryption diminished significantly after World War II ended.
• Detailed documentation of the project was preserved by electrical engineer Donald Bayley, whose personal notes were auctioned in 2023.

Why it Matters

The Delilah project highlights the critical importance of documenting experimental technology to prevent historical innovations from being lost to time. This discovery underscores how early miniaturization efforts laid the conceptual groundwork for the secure, portable digital communications systems that are now standard in modern society.