The present invention relates to a quantum cryptography system for the
secure key generation, especially with signal sources and analysis
channels. The signal sources are arranged spatially separated in such a
manner that the wave fronts of light signals emitted by them superimpose
partially at the input of the quantum channel. The analysis channels are
arranged in such a manner that the wave front of the light signals coming
from the quantum channel are split up spatially and at least two of the
parts are analyzed in a quantum mechanical state.