Brief History of Quantum Cryptography: A Personal Perspective (Invited Paper)
Gilles Brassard · 2005
Quantum cryptography is the only approach to privacy ever proposed that allows two parties (who do not share a long secret key ahead of time) to communicate with provably perfect secrecy under the nose of an eavesdropper endowed with unlimited computational power and whose technology is limited by nothing but the fundamental laws of nature. This essay provides a personal historical perspective on the field. For the sake of liveliness, the style is purposely that of a spontaneous after-dinner speech. It will be seen that the IEEE played a ubiquitous role in this tale. I. PREHISTORY The story begins in the early 1960's, when Stephen Wiesner and Charles Bennett were undergraduates together at Brandeis University. Having many common friends, they enjoyed talking with each other. Later, after Wiesner had gone to grad- uate school at Columbia and Bennett at Harvard, they kept in touch. In particular, the former payed frequent visits to the lat- ter's communal house in Boston. During one of those visits 1 in the late 60's or early 70's 2 , Wiesner told Bennett of his ideas for using mechanics to make banknotes that would be impossible to counterfeit according to the laws of nature, as well as a quantum multiplexing channel, which would allow one party to send two messages to another in a way that the receiving party could decide which message to read but only at the cost of destroying the other message irreversibly. 3