"QC is based on a totally secure Quantum Key Distribution. A crypting key is distributed using quantic properties of particles, e.g. the polarization of a photon. Any intrusion of a third party is detected by a modification of the error rate. The corner stone of QC is Heisenberg principle of uncertainty that implies that the quantic state of a particle cannot be duplicated and that any observation by an eavesdropper eventually destroys the quantic state."
A lényeg, hogy a quantum semmilyen állapota nem lemásolható.