Quantum key distribution

Summary

Quantum key distribution is a way for two parties to build a shared secret key by sending quantum states and talking over a public channel. Its security rests on the laws of quantum mechanics rather than on the hardness of a computational problem. An eavesdropper who measures the quantum states disturbs them, and the parties can detect the disturbance. The first protocol, BB84, was proposed by Bennett and Brassard in 1984.