The U.S. Patent Office granted Patent No. 2,292,387 to Hedy Kiesler Markey and George Antheil for a frequency-hopping secret communication system.
On 11 August 1942, the United States Patent and Trademark Office formally granted U.S. Patent No. 2,292,387, titled "Secret Communication System," to Hedy Kiesler Markey and George Antheil. The patent described a method of frequency-hopping spread spectrum communication designed to make radio-guided torpedoes resistant to jamming by rapidly and unpredictably switching between different radio frequencies in a pattern known only to the transmitter and receiver.
Although the U.S. Navy did not implement the system during World War II — reportedly viewing the piano-roll mechanism as impractical for warship equipment at the time — the patent stands as a remarkable piece of intellectual property credited to a working actress with no formal engineering training, working alongside a composer known for experimental music.
The significance of this patent grew enormously over subsequent decades. The core principle of frequency hopping became a technological cornerstone of secure military communications and, eventually, of civilian wireless technologies including Wi-Fi, Bluetooth, CDMA cellular networks, and GPS. Because the patent had expired by the time these technologies were commercialized, Lamarr and Antheil received no royalties, but recognition of their conceptual contribution grew substantially from the 1990s onward.
This 1942 grant represents a rare instance in history of a Hollywood celebrity holding a substantive technical patent, undermining stereotypes of the era that discouraged women — particularly glamorous film stars — from being taken seriously as inventors or engineers.