Relativistic quantum cryptography on «arrested» photons

A new relativistic quantum cryptosystem is proposed in which the information is carried by the extended single-photon states with orthogonal polarizations and effective length exceeding the communication channel length. The light «arrest» effect is used as a procedure for the detection and preparation of extended states. The cryptosystem is secure against any eavesdropping attempts, because its states are quantized and the propagation velocity is limited. In this scheme, the preparation and detection procedures are local in space but require a finite time, depending on the extension of the states. The preparation for detecting at the receiver end begins before the state left the source at the input end.