Quantum cryptography with coherent-state light: demonstration of a secure data encryption scheme operating at 100 kb/s

Summary form only given. In this work, we present a free-space implementation of quantum cryptography, in which we use secret keys (a short key K appropriately expanded into K´ by use of another encryption mechanism such as a stream cipher) to set the polarization bases between a transmitter and a receiver. The transmitter uses the secret key to randomly choose a polarization basis from a set of M/2 uniformly spanning a great circle on the Poincare sphere.