Stephen Wiesner IEEE Information Theory Society SIGACT News observables polarization photons Charles H. Bennett Thomas J. Watson Research Center Gilles Brassard secure communication BB84 Artur Ekert Dominic Mayers Andrew Yao quantum key distribution
In the early 1970s, Stephen Wiesner, then at Columbia University in New York, introduced the concept of quantum conjugate coding. His seminal paper titled "Conjugate Coding" was rejected by the IEEE Information Theory Society, but was eventually published in 1983 in SIGACT News. In this paper he showed how to store or transmit two messages by encoding them in two "conjugate observables", such as linear and circular polarization of photons, so that either, but not both, of which may be received and decoded. It was not until Charles H. Bennett, of the IBM's Thomas J. Watson Research Center and Gilles Brassard met in 1979 at the 20th IEEE Symposium on the Foundations of Computer Science, held in Puerto Rico, that they discovered how to incorporate Wiesner's findings. "The main breakthrough came when we realized that photons were never meant to store information, but rather to transmit it" In 1984, building upon this work, Bennett and Brassard proposed a method for secure communication, which is now called BB84. Independently, in 1991 Artur Ekert proposed to use Bell's inequalities to achieve secure key distribution. Ekert's protocol for the key distribution, as it was subsequently shown by Dominic Mayers and Andrew Yao, offers device-independent quantum key distribution.
