Telegrapher’s “fingerprint” chart, UK (SOE), 1943–44
How can you tell if a radio message is from your agent…or an imposter? A radio operator’s touch on the keyboard is individual and identifiable. Britain’s Special Operations Executive (SOE) used this chart to “fingerprint” radio operators such as Noor Inayat Khan, preserving detailed records of their touch. Khan’s musical training may have helped her skill, with flying fingers able to tap out Morse code quickly.
