The Quantum Enigma: Finding the Hidden Key

W. CAMPBELL SMITH

Olivier Darrigol

Seth Lloyd

Enigma machines are devices that perform cryptography using pseudo-random numbers. The original enigma machine code was broken by detecting hidden patterns in these pseudo-random numbers. This paper proposes a model for a quantum optical enigma machine and shows that the phenomenon of quantum data locking makes such quantum enigma machines provably secure even in the presence of noise and loss.

Heng Xiao

Jacob Aron

Alan Turing and an army of codebreakers took years to crack the Enigma code during the second world war. Just be thankful the Nazis weren't using a quantum Enigma machine. Quantum key distribution can already keep secret the key to a code. Enigma machines are like souped-up typewriters, with an illuminated panel above the keyboard that also displays the alphabet. Type in a letter and a different letter on the panel lights up, indicating how to encrypt that character. Wired rotors do the scrambling by guiding an electrical signal along a certain path.