Practical Quantum Cryptography for Secure Free-Space Communications
Quantum Cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics and information - theoretically secure post-processing methods. An adversary can neither successfully tap the quantum transmissions, nor evade detection, owing to Heisenberg's uncertainty principle. In this paper, the authors describe the theory of quantum cryptography and the most recent results from their experimental free space system with which they have demonstrated for the first time the feasibility of quantum key generation over a point-to-point outdoor atmospheric path in daylight.